JP2008277064A - Image display device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device with an excellent displaying feature and a long service life by securing reliability in element separation as well as securing low resistance in a scanning signal wiring and reliability in power supply and conduction. <P>SOLUTION: The image display device is provided with an undercut part 25 in between layers insulation film 14 arranged between an image signal wiring 8 and the scanning signal wiring 9 and the scanning signal wiring 9 is made to be a laminated structure of a lower layer film 92 composed of an aluminum film and an upper layer film 94 composed of aluminum alloy film with aluminum as a main component. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a self-luminous flat panel image display device, and more particularly to an image display device in which thin film electron sources are arranged in a matrix.

As one of self-luminous flat panel displays (FPDs) having electron sources arranged in a matrix, a field emission image display (FED: Field Emission Display) using a small and stackable cold cathode or an electron emission type An image display device is known.
In this cold cathode, Spindt type electron source, surface conduction type electron source, carbon nanotube type electron source, metal-insulator-metal laminated MIM (Metal-Insulator-Metal) type, metal-insulator-semiconductor laminated MIS (Metal-Insulator-Semiconductor) type or thin-film type electron source such as metal-insulator-semiconductor-metal type.

  A general self-luminous FPD includes a rear panel having the electron source as described above on a rear substrate made of a glass plate, a phosphor layer, and electrons emitted from the electron source to the phosphor layer. A front panel having an anode for forming an electric field to be formed on a front substrate made of a light-transmitting material suitable for glass, and a frame body that holds internal spaces facing each other at a predetermined interval. And an internal space including a display area formed by the two panels and the frame body is maintained in a vacuum state, and a drive circuit is combined with the display panel.

  Also, a plurality of video signal wirings extending in one direction and arranged in parallel in the other direction perpendicular to the one direction on the rear substrate of the rear panel, and insulation formed to cover the video signal wirings A film and a plurality of scanning signal wirings arranged in parallel in the one direction so as to extend in the other direction on the insulating film and intersect the video signal wiring are sequentially applied. In addition, the electron sources are provided in the vicinity of the intersection of the scanning signal wiring and the image signal wiring, the scanning signal wiring and the electron source are connected by a power supply electrode, and current is supplied from the scanning signal wiring to the electron source. The configuration is common.

  Further, the individual electron sources are paired with a corresponding phosphor layer to constitute a unit pixel. Usually, one pixel (color pixel, pixel) is composed of unit pixels of three colors of red (R), green (G), and blue (B). In the case of a color pixel, the unit pixel is also called a sub-pixel (sub-pixel).

  In addition to the above-described configuration, in the image display device as described above, a plurality of spacing members (spacers) are arranged and fixed in a reduced pressure region including a display region surrounded by the frame body between the back panel and the front panel, The distance between the panels is maintained at a predetermined distance in cooperation with the frame. This spacer is generally composed of a plate-like body formed of an insulating material such as glass or ceramics or a member having some conductivity, and is usually installed at a position where the operation of the pixel is not hindered for each of a plurality of pixels. .

The frame body serving as a sealing frame is fixed to the inner peripheral edge of the back substrate and the front substrate with a sealing member such as frit glass, and the fixing portion is hermetically sealed to form a sealing region. The degree of vacuum inside the reduced pressure region formed by both the substrates and the frame is, for example, about 10 ⁻⁵ to 10 ⁻⁷ Torr.

  A scanning signal wiring lead terminal connected to the scanning signal wiring formed on the rear substrate and an image signal wiring lead terminal connected to the image signal wiring pass through the sealing region between the frame and the substrate.

The aforementioned MIM type electron source is disclosed in, for example, Patent Documents 1 and 2. The structure and operation of the MIM type electron source are as follows. That is, it has a structure in which an insulating layer is interposed between the upper electrode and the lower electrode, and by applying a voltage between the upper electrode and the lower electrode, electrons in the vicinity of the Fermi level in the lower electrode are tunneled. Due to the phenomenon, it passes through the barrier, is injected into the conduction band of the insulating layer, which is the electron acceleration layer, becomes hot electrons, and flows into the conduction band of the upper electrode. Among these hot electrons, those that reach the surface of the upper electrode with energy equal to or higher than the work function φ of the upper electrode are released into the vacuum.
JP 2004-363075 A JP 2006-107741 A

Such an electron source is arranged in a plurality of rows (for example, in the horizontal direction) and a plurality of columns (for example, in the vertical direction) to form a matrix, and a large number of phosphor layers arranged corresponding to each electron source are arranged in a vacuum to form an image. A display device can be configured.
When an image display is performed in the image display device having such a configuration, a driving method called a line sequential driving method is typically employed.
In this method, when displaying 60 still images (60 frames) per second, display in each frame is performed for each scanning signal wiring (horizontal direction). Accordingly, all electron sources corresponding to the number of video signal wirings on the same scanning signal wiring operate simultaneously. A current obtained by multiplying the current consumed by the electron source included in the subpixel {subpixel constituting one color pixel (pixel) for full color display} by the number of all video signal lines flows through the scanning signal wiring during operation. . Since this scanning signal wiring current causes a voltage drop along the scanning signal wiring due to wiring resistance, it prevents a uniform operation of the electron source. In particular, a voltage drop due to the wiring resistance of the scanning signal wiring is a serious problem in realizing a large display device.

  In order to solve this problem, it is necessary to reduce the wiring resistance of the scanning signal wiring. In the case of a thin film type electron source, it is conceivable to lower the resistance of the lower electrode (video signal electrode) or the upper bus electrode wiring (scanning signal wiring) that feeds power to the upper electrode. However, if the thickness of the lower electrode is increased in order to reduce the resistance, the unevenness of the wiring becomes severe, the quality of the electron acceleration layer is deteriorated, and the upper bus electrode and the like are easily disconnected, resulting in a problem in reliability. Therefore, a method of reducing the resistance of the upper bus electrode wiring is preferable.

  In order to reduce the wiring resistance of the upper bus electrode wiring, it is effective to use a thick film material having a small specific resistance. Copper (Cu) has the next smallest resistivity after silver (Ag), is inexpensive, and has a high sputter deposition rate, so it is easy to increase the thickness. Further, Cu is a material suitable for the upper bus electrode wiring because a thick film can be formed by plating. However, Cu is easily oxidized, and when applied to, for example, an FED panel, it is easily oxidized in the high-temperature sealing process. Therefore, it is conceivable to prevent oxidation by sandwiching the upper and lower surfaces of Cu with a metal having high heat resistance and high oxidation resistance. However, most of Cu is not oxidized by sandwiching the upper and lower surfaces of Cu with metal having high oxidation resistance. However, oxidation on the side of the wiring cannot be prevented. It is desirable that the upper bus electrode wiring also has a mechanism for separating the upper electrode in a self-aligned manner, but the undercut portion formed of Cu and the lower metal film is deformed due to oxidation of the side surface of the wiring, and the pixel separation characteristics deteriorate. There is a case.

  In order to reduce the wiring resistance of the upper bus electrode wiring, for example, Ag or gold (Au) electrode formed by screen printing is also effective. In addition, the upper bus electrode wiring has a structure that separates the upper electrode in a self-aligned manner, and a spacer is installed to prevent the spacer from being charged and to prevent mechanical damage to the lower layer wiring due to atmospheric pressure applied to the spacer. (The function of electrically connecting the spacer to the upper bus electrode wiring) is required. However, in screen printing, it is difficult to create a complicated structure for realizing pixel separation characteristics that separate the upper electrodes in a self-aligning manner.

  It is also disclosed that a thick film wiring by screen printing such as Ag is laminated on a thin film wiring by vacuum film formation or the like, but in the case of screen printing wiring using a paste such as Ag or Au, the paste is sintered. In order to burn out the binder, high-temperature heat treatment is performed in the presence of oxygen, such as in the atmosphere, so that the surface of the thin film is oxidized, and the contact resistance between the thin film and the thick film wiring increases, which is substantially low. There is a problem that cannot be resisted.

Furthermore, aluminum (Al) (hereinafter also referred to as aluminum) or aluminum alloy (Al alloy) (hereinafter also referred to as aluminum alloy) material having high oxidation resistance is used as the low resistance material, and the upper and lower electrodes are resistant to oxidation. Patent Document 2 discloses a structure in which the electrode is made of chromium (Cr) or a chromium alloy (Cr alloy) which is higher than Al and has a standard electrode potential higher than that of Al.
In Patent Document 2, Cr or Cr alloy or the like is selectively etched with respect to Al or Al alloy, one of which is a lower layer of Cr or Cr alloy, and the other is a lower layer of Cr or Cr alloy or the like. The electrode forms an undercut with respect to the Al or Al alloy electrode. In order to selectively etch a metal material such as Cr or Cr alloy having a high electrode potential from Al or Al alloy having a low electrode potential and to put undercut by wet etching, a film such as Cr or Cr alloy above the lower layer is used. Control the local battery action between Al or Al alloy and Cr or Cr alloy, etc. by increasing the thickness and limiting the exposure amount of Al or Al alloy not covered with upper layer Cr or Cr alloy, etc. A manufacturing method for securing a cut amount is disclosed.

  In this configuration, the deformation of the undercut portion is suppressed and the self-alignment separation characteristic of the upper electrode can be improved, and the pixel separation characteristic can be obtained even after high-temperature heat treatment in an oxygen-containing atmosphere such as a sealing process of an image display device. A low-resistance upper bus electrode wiring (scanning signal wiring) can be created without deteriorating, thereby providing an image with uniform brightness in the display area.

However, even in the configuration of Patent Document 2 having such characteristics, the scanning signal wiring lower layer Cr can be processed simultaneously with processing different from one of the side wall undercut for element isolation and the other side of the taper processing for contact. It is required and the deterioration of workability is inevitable.
Further, if the taper processing is insufficient, the upper electrode may be disconnected, and the occurrence of disconnection results in poor power supply to the electron source.
Further, the lower layer Cr of the scanning signal wiring may be oxidized due to the influence of the heat treatment that is applied at the time of sealing the panel and the like, and there is a possibility that the conduction fluctuation or the conduction failure may occur.

  The object of the present invention is to solve the above-mentioned problems, to improve the reliability of power supply and conduction, to ensure the reliability of element isolation, and to shorten the manufacturing process, and to display an image with a long life with excellent display characteristics. To provide an apparatus.

In order to achieve the above object, according to the present invention, an undercut portion is formed in an interlayer insulating film disposed between a scanning signal wiring and a video signal wiring, and element separation is performed by dividing the upper electrode at the undercut portion. It is characterized by.
According to the present invention, a second insulating film having an etching rate different from that of the interlayer insulating film is disposed on the interlayer insulating film, and an undercut portion is formed in the second insulating film. The upper electrode is divided to perform element isolation.
Further, the present invention is characterized in that the scanning signal wiring has a laminated film structure of an aluminum film and an aluminum alloy film mainly composed of aluminum.
Furthermore, the present invention is characterized in that the scanning signal wiring has a laminated film structure of an aluminum alloy film containing aluminum as a main component, and the laminated film structure has layers having different specific resistances.

By forming the undercut portion by etching the insulating film to enable element isolation, it is possible to solve the conventional problem of chromium contamination of the Al anodic oxidation solution accompanying chromium dissolution.
In addition, chromium contamination of the electron source can be solved, reliability of electron emission characteristics can be ensured, and a long life can be achieved.
Furthermore, the scanning signal wiring has an aluminum film and an aluminum alloy film composed mainly of aluminum or an aluminum alloy film having a different specific resistance, so that contact taper processing is easier than chromium and processing accuracy is improved. Therefore, the workability can be improved and the disconnection of the upper electrode can be avoided. Further, the resistance increase due to heat treatment received during panel sealing or the like is lower than that of chromium, and the reliability of conduction can be improved.
Furthermore, the laminated film structure of the aluminum alloy films having different specific resistances improves the reliability of holding the bowl shape of the undercut portion as well as the above-mentioned effects, and ensures the reliability of element isolation. it can.

  Hereinafter, the present invention will be described in detail with reference to the drawings of the embodiments.

FIG. 1 to FIG. 3 are schematic views for explaining the configuration of an embodiment of an image display device according to the present invention. FIG. 1 (a) is a plan view, FIG. 1 (b) is a side view of FIG. 2 is a cross-sectional view taken along line AA in FIG. 1B, FIG. 3A is a cross-sectional view taken along line BB in FIG. 2, and a cross-sectional view of the front substrate corresponding to the rear substrate. 3 (b) is an enlarged view of the main part of FIG. 3 (a).
1 to 3, reference numeral 1 is a back substrate, 2 is a front substrate, 3 is a frame, 4 is an exhaust pipe, 5 is a sealing member, 6 is a vacuum region including a display region, 7 is a through hole, 8 Is a video signal wiring, 81 is a field insulating film, 82 is a tunnel insulating layer, 9 is a scanning signal wiring, 92 is a lower layer film, 94 is an upper layer film, 10 is an electron source, 11 is a connection wiring, 12 is a spacer, 13 is an adhesive A member, 14 is an interlayer insulating film, 25 is an undercut portion, 15 is a phosphor layer, 16 is a light-shielding BM (black matrix) film, and 17 is a metal back (anode electrode) made of a metal thin film.

The back substrate and the front substrate 2 indicated by reference numeral 1 have a substantially rectangular shape, and are each composed of a glass plate having a thickness of several mm, for example, about 1 to 10 mm.
Reference numeral 3 denotes a frame having a frame shape. The frame body 3 is made of, for example, a sintered body of frit glass or a glass plate, and is formed into a substantially rectangular shape by itself or a combination of a plurality of members. Is inserted.
The frame 3 is inserted in a peripheral portion between the substrates 1 and 2 and both end surfaces are airtightly joined to the substrates 1 and 2. The thickness of the frame 3 is set to several mm to several tens mm, and the height thereof is set to a dimension substantially equal to the distance between the substrates 1 and 2.
An exhaust pipe 4 is fixed to the back substrate 1.
5 is a sealing member, and this sealing member 5 is composed of, for example, a low melting point frit glass such as PbO: 75-80 wt%, B2 O3: about 10 wt%, others: 10-15 wt%, etc. A glass material including a frit type glass is known, and the frame 3 and the substrates 1 and 2 are joined and hermetically sealed.

A vacuum region 6 including a display region surrounded by the frame 3, both substrates 1 and 2, and the sealing member 5 is evacuated through the exhaust pipe 4, and has a vacuum degree of, for example, 10 ⁻⁵ to 10 ⁻⁷ Torr. keeping. The exhaust pipe 4 is attached to the outer surface of the rear substrate 1 as described above, and communicates with a through hole 7 formed through the rear substrate 1 so that the exhaust pipe 4 is exhausted after exhausting is completed. Is sealed.

  Reference numeral 8 denotes a striped video signal wiring. The video signal wiring 8 is made of, for example, an aluminum (Al) film, an alloy of aluminum and neodymium (Al—Nd alloy), or the like, and is unidirectionally formed on the inner surface of the rear substrate 1. It extends in the (Y direction) and is juxtaposed in the other direction (X direction). As will be described later, a tunnel insulating layer 82 and a field insulating film 81 are provided on the upper surface of the video signal wiring 8. This video signal wiring 8 airtightly penetrates the joining area between the frame 3 and the rear substrate 1 from the vacuum region 6, extends to the end of the long side of the rear substrate 1, and the leading end of the video signal wiring is drawn out. Terminal 8a is used.

  Reference numeral 9 is a stripe-shaped scanning signal wiring, and the scanning signal wiring 9 extends on the video signal wiring 8 in the other direction (X direction) intersecting with this and is arranged in parallel in the one direction (Y direction). Has been. Although details of the scanning signal wiring 9 will be described later, the scanning signal wiring 9 has a laminated film structure of a lower layer film 92 made of an aluminum film and an upper layer film 94 made of an aluminum alloy film mainly composed of aluminum, or has a different specific resistance. It has a laminated film structure of a lower layer film and an upper layer film made of an aluminum alloy film. The scanning signal wiring 9 airtightly penetrates from the vacuum region 6 to the joining region between the frame 3 and the back substrate 1 and extends to the end portion on the short side of the back substrate 1. Terminal 9a is used.

  Reference numeral 10 denotes an electron source. The electron source 10 is a kind of MIM type electron source disclosed in Patent Documents 1 and 2, for example. The electron source 10 includes the scanning signal wiring 9 and the video signal wiring 8. It is provided in the tunnel insulating layer 82 of the video signal wiring 8 with the scanning signal wiring 9 interposed therebetween in the vicinity of the intersection. The electron source 10 is connected to the scanning signal wiring 9 by a connection wiring (upper electrode) 11.

  An interlayer insulating film 14 is disposed between the video signal wiring 8 and the scanning signal wiring 9. Details of the interlayer insulating film 14 will be described later.

Next, reference numeral 12 denotes a spacer. The spacer 12 is made of an insulating material such as a ceramic material, has an unevenly distributed resistance value, and is shaped into a rectangular thin plate shape, and the insulating substrate 121. It is comprised from the coating layer 122 which covers the surface of this and has little uneven distribution of resistance value.
The spacer 12 has a resistance value of about 10 ⁸ to 10 ⁹ Ω · cm, and has a configuration in which the resistance value is unevenly distributed as a whole.
The spacers 12 are substantially parallel to the frame body 3 and are arranged upright every other on the scanning signal wiring 9, and are bonded and fixed to the both substrates 1 and 2 by an adhesive member 13.
The spacer 12 may be bonded and fixed to the substrate only at one end side, and the arrangement is usually set at a position that does not hinder the operation of each pixel.

  The dimensions of the spacer 12 are set according to the substrate dimensions, the height of the frame 3, the substrate material, the spacer spacing, the spacer material, etc. Generally, the height is substantially the same as the frame 3 described above, The thickness can be several tens of μm to several mm or less, the length can be about 20 mm to 1000 mm, and even longer, but a practical value is preferably about 80 mm to 300 mm.

For example, silicon oxide, silicon nitride, silicon, or the like can be used for the interlayer insulating film 14 described above, but silicon nitride is used here.
The interlayer insulating film 14 serves to maintain insulation between the video signal wiring 8 and the scanning signal wiring 9 by filling up the defects in the field insulating film where pinholes exist.

This interlayer insulating film 14 forms an element isolation structure by forming an undercut portion 25 under the side wall of the scanning signal wiring 9.
The element isolation according to the first embodiment is configured such that the scanning signal wiring 9 is electrically connected to one of the electron sources 10 disposed on both sides of the scanning signal wiring 9 and is not electrically connected to the other. It has been implemented.
The undercut portion 25 forms a recess by etching in the interlayer insulating film 14 under the side wall of the scanning signal wiring 9 on the side where the scanning signal wiring 9 is not electrically connected to the electron source 10. The scanning signal wiring 9 is configured to have a bowl shape.
The undercut portion 25 divides the upper electrode 26 connecting the tunnel insulating layer 82 constituting the electron source 10 and the scanning signal wiring 9 to separate the element from the other electron source. On the other hand, the interlayer insulating film 14 is buried under the scanning signal wiring 9 on the conductive side.

Next, on the inner surface of the front substrate 2 to which one end of the spacer 12 is fixed, red, green, and blue phosphor layers 15 are arranged in a window section partitioned by a light-shielding BM (black matrix) film 16. A metal back (anode electrode) 17 made of a metal thin film is provided by, for example, a vapor deposition method so as to cover them, thereby forming a phosphor screen.
The metal back 17 is a light reflecting film for reflecting the light emitted to the side opposite to the front substrate 2, that is, the back substrate 1 side, toward the front substrate 2 side to increase the light extraction efficiency, and on the surface of the phosphor particles. It also has a function to prevent electrification.
Further, although the metal back 17 is shown as a surface electrode, it may be a stripe electrode that intersects the scanning signal wiring 9 and is divided for each pixel column.

Examples of the phosphor include Y ₂ O ₃ : Eu and Y ₂ O ₂ S: Eu for red, ZnS: Cu, Al, Y ₂ SiO ₅ : Tb for green, and ZnS for blue. : Ag, Cl, ZnS: Ag, Al, etc. can be used. The phosphor layer 15 has an average particle diameter of phosphor particles of, for example, 4 μm to 9 μm, and a film thickness of, for example, about 10 μm to 20 μm.

Next, with respect to an embodiment of the manufacturing method of the image display device of the present invention, the manufacturing process of both the signal wiring and the electron source of Embodiment 1 will be described with reference to FIGS.
4 to 15, each figure (a) is a schematic plan view, each figure (b) is a schematic sectional view taken along the line CC of each figure (a), and each figure (c) is each figure (a). In the schematic cross-sectional view taken along the line D-D of FIG. This electron source is a MIM type electron source.

  First, as shown in FIG. 4, a metal film for the video signal wiring 8 is formed on substantially the entire surface of an insulating substrate such as glass constituting the back substrate 1. As a material for the video signal wiring 8, aluminum (Al) or an aluminum alloy mainly composed of aluminum was used. One of the reasons for using Al is that it is possible to use the characteristic that a high-quality insulating film can be formed by anodic oxidation. Here, an Al—Nd alloy doped with 2 atomic% of neodymium (Nd) was used. For film formation, a sputtering method was used, and the film thickness was 600 nm.

After the film formation, a stripe-shaped video signal wiring 8 was formed by a patterning process and an etching process (FIG. 5).
The wiring width of the video signal wiring 8 varies depending on the size and resolution of the image display device, but is about the pitch of the sub-pixel, about 100 to 200 microns (μm). For the etching, for example, wet etching using a mixed aqueous solution of phosphoric acid, acetic acid and nitric acid is used. Since this wiring has a simple and wide stripe structure, the resist can be patterned by inexpensive proximity exposure or printing.

Next, a field insulating film 81 and a tunnel insulating layer 82 are formed on the surface of the video signal wiring 8 to limit the electron emission portion and prevent electric field concentration on the edge of the video signal wiring 8 (FIG. 6).
First, a portion corresponding to a portion that will become an electron emission portion in the future is masked with a resist film at a substantially central portion of the line width on the video signal wiring 8 shown in FIG. 6, and the other portions are selectively thickened by anodic oxidation. Thus, a field insulating film 81 to be a protective insulating film is formed. In this operation, when the formation voltage is set to 100 v to 200 v, the field insulating film 81 having a thickness of about 140 nm to 280 nm is formed.
Thereafter, the resist film is removed and the surface of the remaining video signal wiring 8 is anodized. For example, if the formation voltage is 6 v, a tunnel insulating layer 82 having a thickness of about 10 nm is formed on the video signal wiring 8 (FIG. 6).

Next, an interlayer insulating film 14 is formed by a sputtering method (FIG. 7). This film formation can also use CVD.
As the interlayer insulating film 14, for example, silicon oxide, silicon nitride, silicon or the like is used as described above.
Here, the interlayer insulating film 14 is made of silicon nitride SiN formed by reactive sputtering in an argon (Ar) and nitrogen (N ₂ ) atmosphere, and the film thickness is 200 nm.
This interlayer insulating film 14 plays a role of maintaining insulation between the video signal wiring 8 and the scanning signal wiring 9 by filling up the defects in the field insulating film 81 formed by anodic oxidation, filling the defects.

Next, an aluminum film 91 for the scanning signal wiring 9 was formed by a sputtering method so as to cover the entire surface of the interlayer insulating film 14. The film thickness was 4.5 μm (FIG. 8).
Subsequently, the aluminum film 91 is processed by a photo-etching process, and the video signal wiring is formed at a position between the tunnel insulating layer 82 and a tunnel insulating layer 82 (not shown) of the same color adjacent to and spaced apart from the tunnel insulating layer 82. A lower layer film 92 of the stripe-shaped scanning signal wiring 9 extending in a direction orthogonal to 8 is formed (FIG. 9). The lower layer film 92 has a substantially rectangular cross section perpendicular to the extending direction.
Etching in this processing uses, for example, wet etching with a mixed aqueous solution of phosphoric acid, acetic acid and nitric acid.
Constructing this lower layer film 92 with aluminum exhibits low resistance, and by adjusting the ratio of phosphoric acid, acetic acid, and nitric acid in the etching solution, specifically, by increasing the ratio of nitric acid, adhesion of the resist end face Therefore, the processing is easy and the scanning signal wiring material is preferable.

Next, an opening reaching the surface of the field insulating film 81 is formed in the interlayer insulating film 14 (FIG. 10).
This is provided with an opening 14a having a substantially rectangular plane and a substantially bowl shape in the depth direction. This drilling is possible by photolithography and dry etching.
This opening position is between the one side wall 92a of the lower layer film 92 and the tunnel insulating layer 82 within the line width of the video signal wiring 8, and the opening has a configuration in which the side wall is tapered. Moreover, the shape of the taper is such that the metal film laminated on the upper portion is less likely to cause step breakage at that portion.

Subsequently, an aluminum alloy film 93 mainly composed of aluminum is formed on the entire upper surface such as the lower layer film 92 and the opening (FIG. 11).
This aluminum alloy film 93 is an alloy film of aluminum and neodymium doped with 2 atomic% of neodymium (Nd) described above, and was formed by a sputtering method. The film thickness was set to 300 nm to 600 nm, which is thinner than the lower layer film 92.
After the film formation, the film is processed by a photoetching process, and the upper layer film 94 of the scanning signal wiring 9 is continuously stacked from the upper surface 92b of the lower layer film 92 through one side wall 92a and part of the opening 14a (FIG. 12). .
On the other hand, the other side wall 92c side of the lower layer film 92 is configured such that the upper layer film 94 does not remain from a part of the upper surface to the side wall in consideration of the element isolation. Therefore, the interlayer insulating film 14 also exposes the intermediate portion 14b extending from the outer portion of the side wall 92c to the adjacent scanning signal wiring (not shown) side.
The scanning signal wiring 9 is composed of a laminated film of the upper layer film 94 made of the aluminum alloy film and the lower layer film 92 made of the aluminum film.

On the other hand, when forming the scanning signal wiring 9 with a laminated film structure of an aluminum alloy film, the specific resistance of the aluminum alloy film constituting the lower layer film 92 is smaller than the specific resistance of the aluminum alloy film constituting the upper layer film 94. Form as a thing.
Next, the intermediate portion 14b of the interlayer insulating film 14 made of SiN is etched. This etching is performed by dry etching capable of isotropic etching. In this etching, the interlayer insulating film 14 other than the intermediate portion 14b is covered with a protective film.
This dry etching of SiN is performed using a mixed gas of CF ₄ and O ₂ or a mixed gas of SF ₆ and O ₂ .
By this dry etching, a part of the intermediate part 14b of the interlayer insulating film 14 made of SiN is selectively removed.
By this dry etching, the exposed portion including the intermediate portion 14b is removed. In addition to this, a portion of the intermediate portion 14b that continues below the lower layer film 92 is removed by side etching, and the lower layer film 92 has a bowl shape, and this portion becomes the undercut portion 25 (see FIG. 13).

Next, the interlayer insulating film 14 is processed, the interlayer insulating film 14 on the tunnel insulating layer 82 is removed, and the tunnel insulating layer 82 is exposed. Etching can be performed, for example, by dry etching using a gas mainly composed of CF ₄ or SF ₆ (FIG. 14).
The step of removing the interlayer insulating film 14 on the tunnel insulating layer 82 can be performed simultaneously with the processing of the undercut portion 25.

Next, the upper electrode 26 is formed. As this film formation method, for example, sputtering film formation is used. As the upper electrode 26, for example, a laminated film of iridium (Ir), platinum (Pt), and gold (Au) is used, and the film thickness is set to 3 nm, for example.
The upper electrode 26 is formed so as to continuously cover the field insulating film 81 and the upper layer film 94 from the tunnel insulating layer 82, and is separated from the adjacent scanning signal wiring (not shown) by the undercut portion 25. (FIG. 15).
Through the above steps, the scanning signal wiring 9, the video signal wiring 8, the electron source 10, and the upper electrode 26 on the back substrate 1 are formed.
In the second embodiment, the scanning signal wiring has a different shape between the edge on the conductive side and the edge on the non-conductive side, and the cross-sectional shape in the thickness direction is asymmetrical on the left and right of the central axis of the line. It has become.
The scanning signal wiring has a tapered shape at the conductive edge, and the interlayer insulating film is recessed by side etching at the opposite non-conductive edge, and the scanning signal wiring has a bowl shape.
Due to the difference in edge shape, the upper electrode is continuously formed from the scanning signal wiring to the electron source at the conduction-side edge, whereas the upper electrode is divided at the undercut portion at the non-conduction-side edge portion and adjacent. The device is separated from the electron source.

FIG. 16 is a schematic view corresponding to FIG. 15 for explaining another embodiment of the manufacturing method of the image display device of the present invention. FIG. 16 (a) is a plan view, and FIG. 16 (b) is a plan view of FIG. FIG. 16C is a cross-sectional view taken along the line D-D in FIG. 16A, and the same reference numerals are given to the same parts as those in the above-described figure.
16A to 16C, the scanning signal wiring 9 has a four-layer film configuration.
First, the lower layer film 92 has a three-layer film structure having aluminum alloy films 922 and 923 mainly composed of aluminum on the upper and lower sides with an aluminum film 921 interposed therebetween, and is made of an aluminum alloy film mainly composed of aluminum on the upper side. A four-layer film configuration including an upper layer film 94 is employed.
In the configuration of the third embodiment, in addition to the feature that the scanning signal wiring is made of aluminum and an aluminum alloy, the aluminum alloy film 923 that is in contact with the interlayer insulating film 14 has a feature that can maintain the shape of the ridge in the heating process, It also has features that can contribute to ensuring reliability.

FIG. 17 is a schematic cross-sectional view for explaining another embodiment of the image display device of the present invention. The same parts as those shown in FIG.
In Example 4, the second insulating film 24 having an etching rate different from that of the interlayer insulating film 14 is disposed on the interlayer insulating film 14, and the undercut portion 25 is formed in the second insulating film 24. In this configuration, the upper electrode 26 is divided by the undercut portion 25 to perform element isolation.

  In the fourth embodiment, the element isolation is performed at the undercut portion provided in the second insulating film by utilizing the difference in etching rate with the interlayer insulating film, and the element structure is simplified and the product yield is improved. In addition, the working process can be shortened.

Next, with respect to another embodiment of the method for manufacturing an image display device of the present invention, the manufacturing process of both the signal wiring and the electron source of Embodiment 4 will be described with reference to FIGS.
18 to 26, each figure (a) is a schematic plan view, each figure (b) is a schematic sectional view taken along the line CC of each figure (a), and each figure (c) is each figure (a). In the schematic cross-sectional view taken along the line D-D of FIG. This electron source is a MIM type electron source.

  First, the video signal wiring 8 provided with the field insulating film 81 and the tunnel insulating layer 82 is formed on the substrate. This process is the same as that shown in FIGS.

Next, an interlayer insulating film 14 and a second insulating film 24 are formed thereon by a sputtering method (FIG. 18). This film formation can also use CVD.
As the interlayer insulating film 14, when Si is used for the second insulating film 24, a material having a different etching rate from that of the second insulating film 24 such as silicon oxide or silicon nitride is used.
As will be described later, when the second insulating film 24 is processed by dry etching to form an undercut portion, the etching is performed so that the etching amount of the interlayer insulating film 14 is smaller than that of the second insulating film 24. This is because the material can ensure the selectivity.
Here, silicon nitride SiN formed by reactive sputtering in an Ar and N ₂ atmosphere was used as the interlayer insulating film 14 and the film thickness was 200 nm.
The interlayer insulating film 14 plays a role of maintaining insulation between the video signal wiring 8 and the scanning signal wiring by filling up the defects in the field insulating film 81 formed by anodic oxidation and filling the defects.
On the other hand, Si of the second insulating film 24 was formed by sputtering in an Ar atmosphere using a Si target doped with B, P, or the like. The film thickness was 100 nm to 300 nm.
Doped Si formed by a sputtering method is not activated, and can be used as a very high resistance semi-insulating material, as is the case with an intrinsic semiconductor.
In the case where Si oxide or Si oxynitride is used for the interlayer insulating film 14, the etching rate is further reduced as compared with the coupling using SiN, so that high selectivity with the second insulating film 24 can be obtained.

Next, an aluminum film 91 for the scanning signal wiring 9 was formed by a sputtering method so as to cover the entire surface of the second insulating film 24. The film thickness was 4.5 μm (FIG. 19).
Subsequently, the aluminum film 91 is processed by a photo-etching process, and the video signal wiring is formed at a position between the tunnel insulating layer 82 and a tunnel insulating layer 82 (not shown) of the same color adjacent to and spaced apart from the tunnel insulating layer 82. A lower layer film 92 of the stripe-shaped scanning signal wiring 9 extending in a direction orthogonal to 8 is formed (FIG. 20). The lower layer film 92 has a substantially rectangular cross section perpendicular to the extending direction.
Etching in this processing uses, for example, wet etching with a mixed aqueous solution of phosphoric acid, acetic acid and nitric acid.
Constructing this lower layer film 92 with aluminum exhibits low resistance, and by adjusting the ratio of phosphoric acid, acetic acid, and nitric acid in the etching solution, specifically, by increasing the ratio of nitric acid, adhesion of the resist end face Therefore, the processing is easy and the scanning signal wiring material is preferable.

Next, an opening reaching the surface of the field insulating film 81 is formed in the interlayer insulating film 14 and the second insulating film 24 (FIG. 21).
In this, the openings 14a and 24a having a substantially rectangular plane and a substantially bowl shape in the depth direction are formed substantially concentrically. This drilling is possible by photolithography and dry etching.
This opening position is within the line width of the video signal wiring 8 and between the one side wall 92a of the lower layer film 92 and the tunnel insulating layer 82. Each opening has a taper on the side wall, and a continuous taper in the laminated state. It has a configuration that is handled as a substantially single opening. In addition, the shape of the taper and the film boundary part is such that the metal film laminated on the upper part is less likely to cause step breakage in the part.

Subsequently, an aluminum alloy film 93 mainly composed of aluminum is formed on the entire upper surface such as the lower layer film 92 and the opening (FIG. 22).
This aluminum alloy film 93 is an alloy film of aluminum and neodymium doped with 2 atomic weight% of the above-mentioned neodymium (Nd), and was formed by a sputtering method. The film thickness was set to 300 nm to 600 nm, which is thinner than the lower layer film 92.
After the film formation, the film is processed by a photoetching process, and the upper layer film 94 of the scanning signal wiring 9 is continuously laminated from the upper surface 92b of the lower layer film 92 through one side wall 92a to part of the opening 14a and the opening 24a. FIG. 23).
On the other hand, the other side wall 92c side of the lower layer film 92 is configured such that the upper layer film 94 does not remain from a part of the upper surface to the side wall in consideration of the element isolation. Therefore, the second insulating film 24 also exposes the intermediate portion 24b extending from the outer portion of the side wall 92c to the adjacent scanning signal wiring (not shown) side.
The scanning signal wiring 9 is composed of a laminated film of the upper layer film 94 made of the aluminum alloy film and the lower layer film 92 made of the aluminum film.

On the other hand, when forming the scanning signal wiring 9 with a laminated film structure of an aluminum alloy film, the specific resistance of the aluminum alloy film constituting the lower layer film 92 is smaller than the specific resistance of the aluminum alloy film constituting the upper layer film 94. Form as a thing.
Next, selective dry etching of Si of the second insulating film is performed.
This selective dry etching of Si is performed using a mixed gas of CF ₄ and O ₂ or a mixed gas of SF ₆ and O ₂ .
These gases etch both Si and SiN. However, by optimizing the ratio of O ₂ , the etching selectivity of Si can be increased.
By this dry etching, a part of the second insulating film 24 made of Si disposed on the interlayer insulating film 14 made of SiN is selectively removed.
By this selective dry etching of Si, the exposed portion including the intermediate portion 24b is removed. In addition to this, a portion of the intermediate portion 24b that continues below the lower layer film 92 is removed by side etching, and the lower layer film 92 has a bowl shape, and this portion becomes the undercut portion 25 (see FIG. 24).

Next, the interlayer insulating film 14 is processed, the interlayer insulating film 14 on the tunnel insulating layer 82 is removed, and the tunnel insulating layer 82 is exposed. Etching can be performed, for example, by dry etching using etching gas containing CF ₄ or SF ₆ as a main component (FIG. 25).

Next, the upper electrode 26 is formed. As this film formation method, for example, sputtering film formation is used. As the upper electrode 26, for example, a laminated film of iridium (Ir), platinum (Pt), and gold (Au) is used, and the film thickness is set to 3 nm, for example.
The upper electrode 26 is formed so as to continuously cover the field insulating film 81 and the upper layer film 94 from the tunnel insulating layer 82, and is separated from the adjacent scanning signal wiring (not shown) by the undercut portion 25. (FIG. 26).

In the above embodiment, the structure using the MIM type as the electron source is taken as an example. However, the present invention is not limited to this, and the present invention is also applicable to the self-luminous FPD using the various electron sources described above. The same applies.
Moreover, although neodymium was illustrated as an aluminum alloy, it is not limited to this, For example, as a metal for alloys, various other things are used if necessary.

FIG. 1A is a schematic view for explaining the configuration of an embodiment of an image display device according to the present invention, FIG. 1A is a plan view, and FIG. 1B is a side view of FIG. It is a schematic cross section which follows the AA line of FIG.1 (b). FIG. 3A is a schematic cross-sectional view taken along the line BB in FIG. 2 and a schematic cross-sectional view of a portion of the front substrate corresponding to the back substrate. FIG. 3B is a schematic enlarged view of the main part of FIG. 4A and 4B are schematic views for explaining a manufacturing process of an image display device according to the present invention, in which FIG. 4A is a plan view, FIG. 4B is a cross-sectional view taken along line CC in FIG. ) Is a cross-sectional view taken along the line DD of FIG. FIG. 5A is a plan view, FIG. 5B is a cross-sectional view taken along the line CC in FIG. 5A, and FIG. 5C is a diagram illustrating a manufacturing process of the image display device according to the present invention. These are sectional drawings which follow the DD line of Drawing 5 (a). 6A and 6B are diagrams illustrating a manufacturing process of the image display device according to the present invention, in which FIG. 6A is a plan view, FIG. 6B is a cross-sectional view taken along line CC in FIG. 6A, and FIG. These are sectional drawings which follow the DD line of Drawing 6 (a). FIG. 7A is a plan view, FIG. 7B is a cross-sectional view taken along the line CC of FIG. 7A, and FIG. 7C is a diagram illustrating a manufacturing process of the image display device according to the present invention. These are sectional drawings which follow the DD line of Drawing 7 (a). FIG. 8A is a plan view of the image display device according to the present invention, FIG. 8B is a plan view, FIG. 8B is a cross-sectional view taken along the line CC of FIG. 8A, and FIG. These are sectional drawings which follow the DD line of Drawing 8 (a). FIG. 9A is a plan view, FIG. 9B is a cross-sectional view taken along line CC of FIG. 9A, and FIG. 9C is a diagram illustrating a manufacturing process of the image display device according to the present invention. These are sectional drawings which follow the DD line of Drawing 9 (a). FIG. 10A is a plan view of the image display device according to the present invention, FIG. 10B is a plan view, FIG. 10B is a cross-sectional view taken along line CC of FIG. 10A, and FIG. These are sectional drawings which follow the DD line of Drawing 10 (a). FIG. 11A is a plan view, FIG. 11B is a cross-sectional view taken along the line CC of FIG. 11A, and FIG. 11C is a diagram illustrating a manufacturing process of the image display device according to the present invention. These are sectional drawings which follow the DD line of Drawing 11 (a). FIGS. 12A and 12B are diagrams illustrating a manufacturing process of an image display device according to the present invention, FIG. 12A is a plan view, FIG. 12B is a schematic cross-sectional view taken along line CC in FIG. ) Is a cross-sectional view taken along the line DD in FIG. FIG. 13A is a plan view, FIG. 13B is a schematic cross-sectional view taken along line CC of FIG. 13A, and FIG. 13C is a diagram for explaining a manufacturing process of the image display device according to the present invention. ) Is a cross-sectional view taken along the line DD in FIG. 14A and 14B are diagrams illustrating a manufacturing process of an image display device according to the present invention, in which FIG. 14A is a plan view, FIG. 14B is a schematic cross-sectional view taken along line CC in FIG. ) Is a cross-sectional view taken along the line DD of FIG. FIG. 15A is a plan view, FIG. 15B is a schematic cross-sectional view taken along line CC in FIG. 15A, and FIG. 15C is a diagram illustrating a manufacturing process of an image display device according to the present invention. ) Is a cross-sectional view taken along the line DD in FIG. FIG. 16A is a plan view of the image display device according to another embodiment of the present invention, FIG. 16B is a plan view, and FIG. 16B is a schematic cross-sectional view taken along line CC of FIG. FIG.16 (c) is sectional drawing which follows the DD line | wire of Fig.16 (a). It is a schematic cross section which shows the other Example of the image display apparatus by this invention. FIG. 18A is a plan view, FIG. 18B is a cross-sectional view taken along the line CC in FIG. 18A, and FIG. 18C is a diagram illustrating a manufacturing process of the image display device according to the present invention. FIG. 19 is a cross-sectional view taken along the line DD of FIG. FIG. 19A is a plan view of the image display device according to the present invention, FIG. 19B is a plan view, FIG. 19B is a cross-sectional view taken along line CC in FIG. 19A, and FIG. These are sectional drawings which follow the DD line of Drawing 19 (a). FIG. 20A is a plan view, FIG. 20B is a cross-sectional view taken along the line CC of FIG. 20A, and FIG. 20C is a diagram illustrating a manufacturing process of the image display device according to the present invention. These are sectional drawings which follow the DD line of Drawing 20 (a). FIGS. 21A and 21B are diagrams illustrating a manufacturing process of an image display device according to the present invention, FIG. 21A is a plan view, FIG. 21B is a cross-sectional view taken along line CC in FIG. 21A, and FIG. These are sectional drawings which follow the DD line of Drawing 21 (a). 22A and 22B are diagrams illustrating a manufacturing process of the image display device according to the present invention, in which FIG. 22A is a plan view, FIG. 22B is a cross-sectional view taken along line CC in FIG. 22A, and FIG. These are sectional drawings which follow the DD line of Drawing 22 (a). FIG. 23A is a plan view, FIG. 23B is a schematic cross-sectional view taken along the line CC of FIG. 23A, and FIG. ) Is a cross-sectional view taken along the line DD in FIG. FIGS. 24A and 24B are diagrams illustrating a manufacturing process of an image display device according to the present invention, FIG. 24A is a plan view, FIG. 24B is a schematic cross-sectional view taken along line CC in FIG. ) Is a cross-sectional view taken along the line DD in FIG. FIG. 25A is a plan view, FIG. 25B is a schematic cross-sectional view taken along the line CC of FIG. 25A, and FIG. ) Is a cross-sectional view taken along the line DD of FIG. 26A and 26B are diagrams illustrating a manufacturing process of an image display device according to the present invention, in which FIG. 26A is a plan view, FIG. 26B is a schematic cross-sectional view taken along line CC in FIG. ) Is a cross-sectional view taken along the line DD in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Back substrate, 2 ... Front substrate, 3 ... Frame, 4 ... Exhaust pipe, 5 ... Sealing member, 6 ... Vacuum region including display region, 7 ... -Through-hole, 8 ... Video signal wiring, 81 ... Field insulating film, 82 ... Tunnel insulating layer, 9 ... Scanning signal wiring, 91 ... Aluminum film, 92 ... Scanning signal wiring Lower layer film, 93 ... Aluminum alloy film, 94 ... Scanning signal wiring upper layer film, 10 ... Electron source, 11 ... Connection wiring, 12 ... Spacer, 13 ... Adhesive member, 14. ..Interlayer insulating film, 15 ... phosphor layer, 16 ... light-shielding BM (black matrix) film, 17 ... metal back made of a metal thin film (anode electrode), 24 ... second Insulating film, 25 ... undercut portion, 26 ... upper electrode.

Claims (12)

A plurality of video signal wirings extending in one direction and arranged in parallel in the other direction orthogonal to the one direction, and a plurality of video signal wirings extending in the other direction and arranged in parallel in the one direction so as to intersect the video signal wiring A plurality of scanning signal wirings, an insulating film disposed between the scanning signal wirings and the video signal wirings, and a plurality of scanning signal wirings disposed in the vicinity of intersections of the video signal wirings and the scanning signal wirings. A back substrate comprising an electron source and an electrode constituting a part of the electron source and extending on the scanning signal wiring;
A front substrate comprising a phosphor layer provided corresponding to the electron source, and an anode for applying an accelerating voltage so as to direct electrons emitted from the electron source to the phosphor layer;
A frame disposed between the front substrate and the rear substrate and holding the two substrates at a predetermined interval;
An image display device comprising the frame and a sealing member that hermetically seals both the substrates,
Among the plurality of electron sources arranged across the scanning signal wiring, the plurality of electron sources on one side are electrically connected to the scanning signal wiring through the electrodes, respectively, and the plurality of electron sources on the other side are the insulating film. An image display device, wherein the electrode is divided by an undercut portion formed in a step and insulated from the scanning signal wiring.   The image display device according to claim 1, wherein the insulating film is an interlayer insulating film.   2. The image display device according to claim 1, wherein the insulating film is a second insulating film disposed on the interlayer insulating film and having a different etching rate from the interlayer insulating film.   4. The image display device according to claim 1, wherein the scanning signal wiring has a laminated film structure of an aluminum film and an aluminum alloy film containing aluminum as a main component.   5. The image display device according to claim 4, wherein the scanning signal wiring has a two-layer film structure in which the aluminum film is disposed in a lower layer and an aluminum alloy film mainly composed of aluminum is stacked on the upper layer.   The scanning signal wiring has a three-layer film structure in which an aluminum alloy film mainly composed of aluminum is arranged with the aluminum film sandwiched between lower layers, and a four-layer film structure in which the aluminum alloy film is laminated on the upper layer. The image display device according to claim 4.   The image display device according to claim 4, wherein the scanning signal wiring has a thickness of the aluminum larger than that of other aluminum alloy.   4. The scanning signal wiring has a laminated film structure of an aluminum alloy film containing aluminum as a main component, and the laminated film structure has layers having different specific resistances. Image display device.   9. The image display device according to claim 8, wherein in the laminated film structure, a film having a large specific resistance is a two-layer film structure arranged above a film having a small specific resistance.   9. The image display device according to claim 8, wherein in the laminated film structure, a film structure having three or more layers in which a film having a large specific resistance is arranged above and below and a film having a small specific resistance is disposed therebetween. . A plurality of video signal wirings extending in one direction and arranged in parallel in the other direction orthogonal to the one direction, and a plurality of video signal wirings extending in the other direction and arranged in parallel in the one direction so as to intersect the video signal wiring A plurality of scanning signal wirings, an insulating film disposed between the scanning signal wirings and the video signal wirings, and a plurality of scanning signal wirings disposed in the vicinity of intersections of the video signal wirings and the scanning signal wirings. A back substrate comprising an electron source and an electrode constituting a part of the electron source and extending on the scanning signal wiring;
A front substrate comprising a phosphor layer provided corresponding to the electron source, and an anode for applying an accelerating voltage so as to direct electrons emitted from the electron source to the phosphor layer;
A frame disposed between the front substrate and the rear substrate and holding the two substrates at a predetermined interval;
A manufacturing method of an image display device comprising the frame and a sealing member that hermetically seals both the substrates,
Forming a stripe-shaped video signal wiring having a tunnel insulating layer and a field insulating film on the surface of an insulating substrate constituting the back substrate;
Covering the video signal wiring with the interlayer insulating film;
Forming a stripe-like lower layer film made of an aluminum film on the interlayer insulating film and substantially perpendicular to the video signal wiring and constituting a part of the scanning signal wiring;
Forming an opening penetrating this film in a part of the interlayer insulating film;
Covering the surface including the lower layer film and the opening with a metal thin film made of an aluminum alloy containing aluminum as a main component;
Processing the metal thin film to form an upper film continuously covering one side wall from the upper surface of the lower film; and
Removing a part of the interlayer insulating film and forming an undercut portion under the other side wall of the lower layer film;
Removing the film laminated on the tunnel insulating layer of the video signal wiring to expose the tunnel insulating layer;
Forming an upper electrode film from the tunnel insulating layer to the scanning signal wiring;
The upper electrode film is divided by the undercut portion to separate the element from the adjacent scanning signal wiring, and the upper portion is continuously extended from the tunnel insulating layer to the top surface through the one side wall of the scanning signal wiring. A method of manufacturing an image display device, comprising a step of forming an electrode. A plurality of video signal wirings extending in one direction and arranged in parallel in the other direction orthogonal to the one direction, and a plurality of video signal wirings extending in the other direction and arranged in parallel in the one direction so as to intersect the video signal wiring A plurality of scanning signal wirings, an insulating film disposed between the scanning signal wirings and the video signal wirings, and a plurality of scanning signal wirings disposed in the vicinity of intersections of the video signal wirings and the scanning signal wirings. A back substrate comprising an electron source and an upper electrode constituting a part of the electron source and extending on the scanning signal wiring;
A front substrate comprising a phosphor layer provided corresponding to the electron source, and an anode for applying an accelerating voltage so as to direct electrons emitted from the electron source to the phosphor layer;
A frame disposed between the front substrate and the rear substrate and holding the two substrates at a predetermined interval;
A method of manufacturing an image display device comprising a sealing member that hermetically seals the two substrates and the frame,
Forming a stripe-shaped video signal wiring having a tunnel insulating layer and a field insulating film on the surface of an insulating substrate constituting the back substrate;
A step of covering the video signal wiring with an interlayer insulating film;
Forming a second insulating film having an etching rate different from that of the interlayer insulating film on the interlayer insulating film;
Forming a stripe-like lower layer film made of an aluminum film on the second insulating film and substantially perpendicular to the video signal wiring and constituting a part of the scanning signal wiring;
A step of forming concentric openings penetrating each film in a part of the interlayer insulating film and the second insulating film;
Covering the surface including the lower layer film and the opening with a metal thin film made of an aluminum alloy containing aluminum as a main component;
Processing the metal thin film to form an upper film continuously covering one side wall from the upper surface of the lower film; and
Removing a part of the second insulating film to form an undercut portion under the other side wall of the lower layer film;
Removing the film laminated on the tunnel insulating layer of the video signal wiring to expose the tunnel insulating layer;
Forming an upper electrode film from the tunnel insulating layer to the scanning signal wiring;
The upper electrode film is divided by the undercut portion to separate the element from the adjacent scanning signal wiring, and the upper portion is continuously extended from the tunnel insulating layer to the top surface through the one side wall of the scanning signal wiring. A method of manufacturing an image display device, comprising a step of forming an electrode.

Images