JPH0554839A - Fluorescent character display panel - Google Patents

Abstract

PURPOSE:To protect a semiconductor device from electron beams and external light rays by forming a second passivation layer of a metal film and an insulating film on a passivation layer on the surface of the semiconductor device except on a bonding pad and dicing. CONSTITUTION:A second passivation layer 13 comprising an aluminum covering layer and a surface protecting film of an insulating layer is formed on a passivation layer on the surface of a driving semiconductor device 2 except on a bonding pad 11 and a dicing portion 12. The device 2 can thus be protected from electron beams, external light rays or cathode-forming material, etc., coming from a filament, thereby enabling stable operation of the same. Because there is no shield, tolerance is given to a three-dimensional structure between the device and the filament and the packaging area of the device can be reduced to the required minimum size for a wire-bonding area and so the size of a fluorescent character display panel can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent display panel in which a driving semiconductor element is incorporated in a vacuum envelope, and more particularly, the driving semiconductor element is formed from an electron beam, an external light beam, or a cathode constituent material flying from a filament. Regarding the structure to protect.

[0002]

2. Description of the Related Art Conventionally, as a method of protecting a driving semiconductor element from an electron beam, an external light ray, or a cathode constituent substance flying from a filament, a shield made of metal is provided between the driving semiconductor element and the filament. .. That is, this type of shield is integrally formed with the filament support using the same metal plate and shaped, or by forming the shield and the filament support separately and performing the necessary shaping, then welding or the like. I used them in combination.

More specifically, as shown in FIG. 3A, the shield 1 has a driving semiconductor element 2 and the eaves 3 extending in all directions and the minimum size required to cover the wire bonding area 10. As shown in FIG. 3B, the shield connecting portion 5 connecting the filament support 4 and the shield 1 is plastically deformed to form a three-dimensional shape. Here, the three-dimensional shaping part is a fixed part 7 for supporting the filament, a getter mounting part 8, a shield 1, a shield connecting part 5, and an eave 3 extending in all directions. A shield support structure was used for the other parts, which also serve as reinforcement of the filament support 4 and are used as a part of the filament support 4 in a flat state.

The filament support 4 is also integrated with the external lead 6 and the shield support structure covers the driving semiconductor element 2 and the wire bonding area 10 so as to cover the cover glass and the anode substrate sealing portion 9. A fluorescent display panel has been manufactured in which a driving semiconductor element is housed in a vacuum envelope by sandwiching it in a vacuum envelope.

[0005]

As described above, the conventional shield has a size necessary to cover the driving semiconductor element and the wire bonding area, and is provided between the driving semiconductor element and the filament. As a result, the element forming surface of the driving semiconductor element is protected from the electron beam, the external light beam, the cathode constituent material flying from the filament, and the like. The space is bigger,
Since a constant space is required between the filament and the shield, and between the driving semiconductor element and the shield, the three-dimensional structure of the fluorescent display panel is required to be more rigorous than conventional fluorescent display panels, making the manufacturing process difficult. In some cases, it may be a great limitation in securing the electrical characteristics.

More specifically, as shown in FIG. 4, the shield 1 is obliquely downward from the boundary between the wire bonding area 10 and the minimum flat portion required to cover the driving semiconductor element 2 and the wire bonding area 10. It has an eaves 3 that stretches to the ground. Since the eaves 3 are formed so as to extend obliquely downward, the dimension in the expanded state before the three-dimensional shaping needs to be 0.3 to 0.5 mm longer than the projected dimension after the three-dimensional shaping. 0.6 to 1.0 on both sides of
In addition to the required mm, the distance between the shield 1 and the filament support 4 or the grid support frame 14 adjacent to both sides of the shield 1 is set so as to allow a margin of a fitting of a shaping type when three-dimensionally shaping them. 0.2 to 0.5 mm is required, and 0.4 to 1.0 mm is required on both sides. Furthermore, considering the positional deviation in the assembly process, the flat part of the shield 1 is 0.3 mm more than the outermost part of the wire bonding area 10.
It is necessary to extend to the outer side of 0.5 mm and 0.6 to 1.0 mm on both sides. As a result of these, it can be seen that it is necessary to make the wire bonding area 1.6 to 3.0 mm longer than the minimum required dimension only by providing the shield.

Due to this extra dimension, the size of the fluorescent display panel becomes large, and the dead space becomes large as compared with a normal type fluorescent display panel without a built-in driving semiconductor element, which is disadvantageous in external dimensions. Become. On the contrary, if this size is reduced, the manufacturing process becomes difficult because there is no room in the three-dimensional structure, which may cause a decrease in the manufacturing yield of the fluorescent display panel in which the driving semiconductor element is built in the vacuum envelope. Become.

On the other hand, the brightness in the fluorescent display panel mainly depends on the distance between the filament and the grid, the distance between the filament and the anode, the grid voltage, and the anode voltage.
The distance from the anode is important. In order to secure a predetermined brightness, this interval is quite narrow, and its value is about 1 mm. That is, it is necessary to arrange the driving semiconductor element and the shield in this space. Here, if there is a margin between the filament and the shield and between the driving semiconductor element and the shield, the manufacturing process is not difficult and the manufacturing yield can be increased, but the distance between the filament, the grid, and the anode is large. There is a fatal defect that it spreads and a predetermined brightness cannot be secured. Therefore, there is no room in the three-dimensional structure,
Even if the manufacturing process is difficult and it is difficult to maintain a high manufacturing yield, the spacing between the filament and the shield, and the driving semiconductor element and the shield must be strictly controlled.

[0009]

A fluorescent display panel according to the present invention is such that a metal coating is formed on a passivation layer excluding a bonding pad and a dicing portion on a surface of a driving semiconductor element, and a surface is further covered with an insulating layer. By using the driving semiconductor element having the second passivation layer with the protective film formed thereon, the driving semiconductor element is protected from the electron beam, the external light beam, or the cathode constituent substances flying from the filament without using a shield, and is stable. It enables the operation.

[0010]

The present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a first embodiment of the present invention.
In the driving semiconductor element 2, the bonding pad 11 and the dicing portion 12 are left, and the second passivation film 13 including an aluminum layer and an insulating layer is formed on the insulating layer which is a conventional passivation layer. On the other hand, after forming a circuit pattern, electrode terminals (not shown), and a bonding pad 16 on the glass substrate 15 with an aluminum film, an insulating layer, a segment electrode, a phosphor layer, and
A frit glass layer for sealing (neither is shown) is formed. Next, the driving semiconductor element 2 is die-bonded to the center of the wire bonding area 10, and the predetermined bonding pad 11 of the driving semiconductor element 2 and the glass substrate 1 are bonded.
After connecting with the bonding pad 16 on 5 by the bonding wire 17, the electrode component is placed at a predetermined position, and at the same time, the tip of the external lead is mechanically contacted with the electrode terminal on the glass substrate. Combine with cover glass and seal at about 450 ° C, then evacuate,
The fluorescent display panel was completed.

FIG. 2 is a perspective view showing a second embodiment of the present invention. The driving semiconductor element 2 has a bonding pad 11
A second passivation film 13 composed of an aluminum layer and an insulating layer is formed on the insulating layer which is a conventional passivation layer while leaving the dicing portion 12 and at the same time a part of the aluminum layer is extended to a new bonding pad. A bonding pad 18 for the second passivation film is formed.

On the other hand, similarly to the first embodiment, the glass substrate 1
After forming a circuit pattern, an electrode terminal (neither of which is shown), and a bonding pad 16 on the aluminum film 5, an insulating layer, a segment electrode, a phosphor layer, and
A frit glass layer for sealing (neither is shown) is formed. Next, the driving semiconductor element 2 is die-bonded to the center of the wire bonding area 10, and the predetermined bonding pad 11 and the glass substrate 15 of the driving semiconductor element are bonded.
A bonding wire 17 connects the upper bonding pad 16. At this time, the bonding pad 18 for the second passivation film newly provided on the driving semiconductor element 2 is connected by the bonding wire 17 to the bonding pad 19 which is also newly provided on the glass substrate and is connected to the filament potential. .. After this, as in the first embodiment, the electrode component is placed at a predetermined position again, and at the same time, the tip of the external lead wire is mechanically brought into contact with the electrode terminal on the glass substrate, and combined with the cover glass. The fluorescent display panel was completed by sealing at 450 ° C. and then evacuating.

Next, a third embodiment of the present invention will be described with reference to FIG. The driving semiconductor element 2 is the bonding pad 1
A second passivation film 13 including a molybdenum layer and an insulating layer is formed on the insulating layer which is a conventional passivation layer, leaving 1 and the dicing portion 12. On the other hand, after forming a circuit pattern, electrode terminals (not shown), and a bonding pad 16 on the glass substrate 15 with an aluminum film, an insulating layer, a segment electrode, a phosphor layer, and a frit for sealing at predetermined portions. A glass layer (neither shown) is formed. Next, after connecting the predetermined bonding pad 11 of the driving semiconductor element 2 and the bonding pad 16 on the glass substrate 15 with the bonding wire 17, the electrode component is placed at a predetermined position and at the same time the tip of the external lead lead. Mechanically contacting the electrode terminals on the glass substrate and combining with the cover glass
The fluorescent display panel was completed by sealing at 50 ° C. and then evacuating.

Although aluminum and molybdenum are used as the metal coating layer in the above embodiment, the present invention is not limited to this.

[0015]

As described above, by using the driving semiconductor element whose surface is protected by the second passivation film composed of the metal coating layer and the insulating layer, the cathode structure that comes out from the electron beam, the external light beam or the filament is used. Protecting the driving semiconductor element from substances etc. enabled stable operation. Furthermore, by fixing the metal coating layer forming the second passivation film to the filament potential, there is an effect of repelling electrons emitted from the filler, and more stable operation of the driving semiconductor element was possible.

On the other hand, since there is no shield, there is a margin in the three-dimensional structure between the driving semiconductor element and the filament, and the mounting area of the driving semiconductor element can be the minimum size required for the wire bonding area. Moreover, the size of the fluorescent display panel does not increase. That is, the dead space can be made smaller as compared with the conventional fluorescent display panel in which the driving semiconductor element having the shield is built in the vacuum envelope, which is advantageous in terms of external dimensions and allows a three-dimensional structure to have a margin. The manufacturing process is not difficult, and the manufacturing yield can be kept high.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a second embodiment of the present invention.

3A and 3B show a shield structure in a conventional fluorescent display panel, wherein FIG. 3A is a plan view and FIG. 3B is a perspective view.

FIG. 4 is a cross-sectional view showing a shield structure in a conventional fluorescent display panel.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Shield 2 Driving semiconductor element 3 eaves 4 Filament support 5 Shield connection part 6 External extraction lead 7 Fixing part 8 Getter mounting part 9 Encapsulation part 10 Wire bonding area 11 Bonding pad on chip 12 Dicing part 13 Second passivation Membrane 14 Grid support frame 15 Glass substrate 16 Bonding pad on substrate 17 Bonding wire 18 Second passivation film bonding pad 19 Potential fixing bonding pad

Claims (1)

[Claims] 1. In a fluorescent display panel in which a driving semiconductor element is built in a vacuum envelope, a metal coating is formed on a passivation layer excluding a bonding pad and a dicing portion on the surface of the driving semiconductor element, and further, A fluorescent display panel comprising a driving semiconductor element having a second passivation layer having a surface protective film formed of an insulating layer.