JPH0917358A - Electron source substrate and its manufacture and image forming device - Google Patents

Abstract

PURPOSE: To reduce characteristic dispersion of a surface conduction type electron emitting element by continuing a contact hole formed in a position separate from upper wiring with the element in the direction for crossing lower wiring. CONSTITUTION: X directional wiring (lower wiring) 72 is formed on an insulating substrate 11 cleaned by a detergent, pure water and an organic solvent by a conductive material such as Cr and Au by a vacuum film forming process or the like. Next, an inter-layer insulating layer 111 of an insulating film is formed by a vacuum evaporation method or the like. Next, a photoresist pattern is formed so that respective element parts continue with each other in the direction for crossing the lower wiring 7, and the inter-layer insulating layer 111 is etched by using this as a mask, and a contact hole is formed. Next, element electrodes 76 and 77 are formed by a vacuum evaporation method or the like, and a connecting part 114 in which the contact hole is embedded is formed by a printing method or the like, and Y directional wiring (upper wiring) 73 is formed by a vacuum film forming process or the like, and after an organic metallic complex or the like is accumulated, an electron emitting thin film having a thin film containing an electron emitting part is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron source and an image forming apparatus such as a display device, which is an application of the electron source, and more particularly, to an electron source substrate provided with a large number of surface conduction electron-emitting devices using fine particles as electron-emitting portions, The present invention relates to a method of manufacturing an electron source substrate and an image forming apparatus such as a display device that is an application thereof.

[0002]

2. Description of the Related Art Conventionally, two types of electron emitting devices, a thermionic electron source and a cold cathode electron source, are known. Cold cathode electron sources include field emission type (hereinafter abbreviated as FE type), metal / insulating layer / metal type (hereinafter abbreviated as MIM type), surface conduction type electron emission devices (hereinafter abbreviated as SCE), and the like. .

As an example of the FE type, W. P. Dyke &
W. W. Dolan, "Field Emissio"
n ", Advance in Electron Ph
ysics, 8, 89 (1956) or C.I. A. S
pindt, "PHYSICAL Property"
s of thin-film field emis
sion cathodes with mollybd
enium cones ", J. Appl. Phy
s. , 47, 5248 (1976) and the like are known.
Examples of the MIM type include C.I. A. Mead, "The t
unnel-emission amplifier,
J. Appl. Phys. , 32, 646 (1961)
Etc. are known. Examples of the SCE type include: I. E
Linson, Radio Eng. Electro
n Phys. 10 (1965) and so on. The SCE type utilizes a phenomenon in which electron emission occurs when a current flows through a small-area thin film formed on a substrate in parallel with the film surface. As the surface conduction electron-emitting device, a device using the SnO ₂ thin film by the above-mentioned Erinson, Au,
Thin film [G. Dittmer: "Thin S
old Films ", 9, 317 (1972)],
In ₂ O ₃ / SnO ₂ thin film [M. Hartw
ell and C.I. G. FIG. Fonstad: "IEEE
Trans. ED Conf. 519 (197
5)], using a carbon thin film [Hisashi Araki et al .: Vacuum,
26, No. 1, p. 22 (1983)].

As a typical element structure of these surface conduction electron-emitting devices, the above-mentioned M. The Hartwell device configuration is shown in FIG. In FIG. 1, reference numeral 1 denotes an insulating substrate. Reference numeral 4 denotes a conductive thin film, which is composed of a metal oxide thin film or the like formed by sputtering on an H-shaped pattern, and the electron emitting portion 3 is formed by an energization process called forming described later.
Reference numeral 4 denotes a thin film including an electron-emitting portion. In the figure, L1 is set to 0.5 to 1 mm and W is set to 0.1 mm.

Conventionally, in these surface conduction electron-emitting devices, the electron-emitting portion forming thin film 4 is formed before the electron emission.
It was general that the electron emitting portion 3 was formed in advance by an energization process called forming. That is, forming means that a voltage is applied to both ends of the electron-emitting-portion forming thin film 4 to locally destroy, deform or alter the electron-emitting-portion forming thin film so that the electron emission is in a high resistance state. To form part 3. In the electron emitting portion 3, a crack is generated in a part of the electron emitting portion forming thin film 4, and electrons are emitted from the vicinity of the crack. Hereinafter, the electron emitting portion forming thin film 4 including the electron emitting portion formed by forming is referred to as a thin film 4 including an electron emitting portion. The surface-conduction electron-emitting device that has undergone the forming process is one in which electrons are emitted from the electron-emitting device 3 described above by applying a voltage to the thin film 4 including the electron-emitting device described above and passing a current through the device. .

The above-mentioned surface conduction electron-emitting device has an advantage that a large number of devices can be arrayed over a large area because it has a simple structure and is easy to manufacture. Therefore, various applications that make use of this feature are being studied. For example, a charged beam source, a display device, and the like can be given. An example of an array of a large number of surface conduction electron-emitting devices is an electron source substrate in which surface conduction electron-emitting devices are arranged in parallel and a large number of rows in which both ends of each element are connected by wiring are arranged. To be (For example, Japanese Unexamined Patent Publication No. 1-031332) Further, in Japanese Unexamined Patent Publication No. 06-342636 by the present applicant, a surface conduction electron-emitting device having a selection means for selecting a device row and a modulation wave for applying a biased signal. There are an electron source and an image forming apparatus in which are arranged in a matrix. The structure of each surface conduction electron-emitting device arranged in this matrix is shown in FIG. In the figure, 51 is an insulating substrate, 59 is an element wiring electrode, 50 is an insulating layer, 52 and 53 are element electrodes, 5
4 is an electron emission part.

[0007]

However, in the above-mentioned conventional example, since the contact hole is surrounded by the upper wiring and each element is independent, the electron emitting portion is also surrounded by the upper wiring, and the Langmuir-Blodgett is also present. Law (L
(B method), or a mixture of an organic metal and an amphipathic material (binder) suitable for deposition using the LB method is deposited as a conductive film,
Due to the influence of the step due to the upper wiring, there is a problem that the distribution of the conductive film is deteriorated, which causes variations in device characteristics. In view of the above drawbacks, the present invention has been made to eliminate the above problems.

[0008]

That is, the present invention made to achieve the above object is to provide an electron source substrate in which a large number of surface conduction electron-emitting devices are arranged in a matrix on an insulating substrate. The electron source substrate is characterized in that the upper wiring and the contact hole are formed apart from each other and the contact hole is continuous with the element in a direction intersecting with the lower wiring.

The present invention further comprises: a.) Cleaning an insulating substrate, and then forming a lower wiring with a conductive material on the substrate by a vacuum process, a photolithography process or a printing process, and b.) A vacuum vapor deposition method, a printing process. An insulating film as an interlayer insulating layer by a sputtering method or a sputtering method, and c.) A. A photoresist pattern for forming a contact hole is formed so that each element portion is continuous in a direction intersecting the lower wiring formed in step d.) The interlayer insulating layer is etched using this as a mask, and d.) Vacuum evaporation method , A printing method, a sputtering method, a photography technique, or etching is used to form an element electrode, and e.) A printing method, a photolithography technique, and a vacuum film formation method are used to form a connection portion for filling a contact hole. ． The upper wiring is formed in the same manner as in f.) The conductive thin film is deposited by the Langmuir-Broggett method to deposit an organometallic complex or a mixture of an organometallic complex and an amphipathic material, followed by firing to deposit a thin film for electron emission. The present invention provides a method for manufacturing an electron source substrate for forming a substrate.

The present invention also provides an image forming apparatus produced by using the electron source substrate.

According to the present invention, with the above structure, the step due to the upper wiring is eliminated in the direction intersecting the lower wiring with the portion forming the thin film including the electron emitting portion, and the LB method is used as compared with the conventional structure. It is possible to reduce the film thickness distribution caused by the step when the electron emitting portion is formed by using it, and thereby reduce the distribution of device characteristics.

Hereinafter, Examples 1 and 2 of the present invention, which will be described later, will be described.
FIG. 2 shows the structure of the electron-emitting device of the present invention according to FIG. 2, and the manufacturing procedure thereof is shown below in accordance with FIG. Step-a After cleaning the insulating substrate 11 with a detergent, pure water, and an organic solvent, a conductive material such as Cr, Au, Ti, or Cu is formed on the substrate 11 by a vacuum film forming process, a photolithography process, a printing process, or the like. The lower wiring 72 is formed. ((A) in FIG. 3) As the insulating substrate, quartz glass, glass with a low content of impurities such as Na, soda lime glass, a glass substrate having SiO ₂ formed on its surface, and a ceramic substrate such as alumina are used. Step-b Next, an insulating film is formed as the interlayer insulating layer 111 by a vacuum evaporation method, a printing method, a sputtering method, or the like. Process-c Next, the contact hole, which is a feature of the present invention, is processed by the process-
The contact hole 113, which is a feature of the present invention such that each element portion is continuous in a direction intersecting the lower wiring formed in a, is formed by forming a photoresist pattern and etching the interlayer insulating layer 111 using this as a mask. To be formed. ((A) of FIG. 3) Step-d Next, the device electrodes 76 and 77 are formed by using a vacuum evaporation method, a printing method, a sputtering method photography technique, an etching technique, or the like. ((C) of FIG. 3) The material of the element electrode may be any material as long as it exhibits conductivity.
A printed conductor composed of a metal such as i, Cr, Au, Mo, W, Ti, Al, Cu, Pd, a metal such as Pd, Ag, Au, RuO ₂ , Pd-Ag or a metal oxide and glass. , Transparent conductive materials such as In ₂ O ₃ —SnO ₂ and semiconductor materials such as polysilicon. Step-e A connection part to be embedded in the contact hole is formed by using a printing method, a photolithography technique and a vacuum film forming method. Next step-a
Similarly, the upper wiring 73 is formed. ((D) of FIG. 3) Step-f Next, the conductive thin film 4 was formed by using the LB method, an organometallic complex,
Alternatively, a mixture of an organometallic complex and a suitable amphipathic material is deposited and then fired to form an electron emission thin film having a thin film including an electron emission portion.

The electron source substrate in which the surface conduction electron-emitting devices are arranged in a matrix by connecting the contact holes to the devices in the direction intersecting the lower wiring by the above steps, has a film thickness distribution of the thin film for forming the electron-emitting portion. By reducing
It is possible to reduce variations in the characteristics of the respective elements after conducting the energization forming, as compared with the related art. Examples will be described below.

[0014]

【Example】

Example 1 This example shows an example of producing an electron source substrate in which surface conduction electron-emitting devices in which contact holes are connected to devices in a direction intersecting a lower wiring are arranged in a matrix.

Step-a A pattern is formed by a photoresist (RD-2001N-41, manufactured by Hitachi Chemical Co., Ltd.) on soda lime glass washed with an organic solvent, and a 100 A thick T film is formed by vacuum evaporation.
i, Au with a thickness of 6000 A, and Cr with a thickness of 300 A were sequentially laminated, and then the photoresist pattern was dissolved with an organic solvent, and the Cr / Au / Ti deposited film was lifted off to form a lower wiring of a desired shape. .

Step-b Next, an interlayer insulating layer made of a silicon oxide film having a thickness of 1.2 μm was deposited by RF sputtering.

Step-c A pattern for forming a continuous contact hole is formed in the device in a direction intersecting with the lower wiring using a photoresist, and RIE (Rea) is performed using CF ₄ and H ₂ gas.
The contact layer was formed by etching the insulating layer by the active ion etching method.

Step-d: Ti having a thickness of 50 A and P having a thickness of 300 A are formed by the sputtering method.
t were sequentially deposited.

Next, a pattern consisting of element electrodes and a gap between the element electrodes was formed with a photoresist (AZ1370, manufactured by Hoechst) and dry etching was performed. The dry etching was performed by using Pt as a mixed gas of HBr / Ar and Ti as a mixed gas of HBr / BCl ₃ . After completion of dry etching, the photoresist was removed with an organic solvent. The distance between the device electrodes was 3 μm, and the width of the device electrodes was 300 μm.

Step-e On this, a pattern to be an electrode for filling the upper wiring and the contact hole is formed with a photoresist (RD-20).
00N-41, manufactured by Hitachi Chemical Co., Ltd.), Ti of 300 A in thickness and Au of 1.0 μm in thickness are sequentially laminated by vacuum deposition, and then the photoresist pattern is dissolved in an organic solvent, and unnecessary portions are lifted off. Was removed to form an upper wiring having a desired shape and a buried electrode for a contact hole. Step-f A film made of a mixture of a palladium acetate alkylamine complex and docosanoic acid was formed on the surface of the substrate by the LB method. The laminated film thickness was 250 layers. Then 300 ° C
For 10 minutes.

Further, a pattern to be a thin film for forming an electron emitting portion was formed with a photoresist (OMR8320cp, manufactured by Tokyo Ohka Co., Ltd.) and dry etching was performed. Dry etching was performed with Ar. After that, the photoresist was removed by treating with a UV / O3 asher at 150 ° C. for 30 minutes.

Through the above steps, the lower wiring, the interlayer insulating film, the upper wiring, the device electrode, and the electron emitting portion forming thin film were formed on the insulating substrate.

Next, a voltage was applied between the device electrodes to energize the thin film for forming the electron emitting portion to form an electron emitting portion.

The electron source substrate thus prepared has a lower wiring than that of the conventional structure when the electron emission thin film is formed by the LB method, as compared with the conventional electron source substrate not using the present invention. Since the step due to the upper wiring in the element in the direction is eliminated, the film thickness distribution is improved and the variation in the characteristics of the element is reduced.

Embodiment 2 In this embodiment, an image forming apparatus using an electron source substrate in which surface conduction electron-emitting devices in which contact holes are connected to devices in a direction intersecting with a lower wiring are arranged in a matrix, and the image forming apparatus is produced. Show the method.

[Step a] was performed in the same manner as in Example 1.

In [step b], PS is used as an insulating film.
A G (phosphosilicate glass) film was formed to a thickness of 1 μm.

Example 1 from [step c] to [step e]
Same as above.

[Step f] A film made of a mixture of palladium acetate alkylamine complex and docosanoic acid was formed by the LB method. The laminated film thickness was 300 layers.

After that, UV irradiation is performed for 8 hours in an O ₃ atmosphere.
Then, heat treatment was performed at 200 ° C. for 40 minutes to form palladium oxide.

Next, a photoresist (AZ1370-S) is used.
F, manufactured by Hoechst Co., Ltd.) to form a desired pattern of the thin film for forming an electron emitting portion, and the palladium oxide in an unnecessary portion was removed by dry etching, and then the resist was removed.

Through the above steps, the lower wiring 72, the interlayer insulating layer 111, the upper wiring 73, and the device electrode 5 are formed on the insulating substrate.
2, 53, a thin film for forming an electron-emitting device portion was formed.

An example in which a display device is constructed using the electron source substrate thus created will be described with reference to FIG. After fixing the created electron source substrate on the rear plate, the face plate 86 (glass substrate 83
A fluorescent film 84 and a metal back 85 are formed on the inner surface of the. Frit glass was applied to the joint between the support frame 82 and the rear plate 81, and was sealed by firing at 400 ° C. to 500 ° C. for 30 minutes or more in the air or a nitrogen atmosphere. Further, the frit glass was also used to fix the substrate to the rear plate 81. In FIG. 1, 74 is an electron-emitting device, and 72 and 73 are lower and upper wirings in the X and Y directions, respectively. In the case of monochrome, the fluorescent film 84 is composed of only the phosphor, but in the present embodiment, the phosphor adopts a stripe shape, only the black stripe is formed first, and the phosphor of each color is applied to the gap portion, A fluorescent film was created. As a material for the black stripe, a glass substrate 83 made of a commonly used material containing graphite as a main component was used, and a slurry method was used as a method for applying the phosphor. A metal back 85 is usually provided on the inner surface side of the fluorescent film 84. The metal back was produced by performing a smoothing treatment (usually called filming) on the inner surface of the fluorescent film after producing the fluorescent film, and then vacuum-depositing Al. The face plate 86 may be provided with a transparent electrode (not shown) on the outer surface side of the fluorescent film in order to further increase the conductivity of the fluorescent film 84.
In this example, since sufficient conductivity was obtained only with the metal back, it was omitted. At the time of performing the above-mentioned sealing, in the case of color, since the phosphors of each color must correspond to the electron-emitting devices, sufficient alignment was performed. An exhaust pipe (not shown) is provided for the atmosphere in the glass container completed as described above.
Through a vacuum pump to reach a sufficient degree of vacuum, and then a voltage is applied between the electrodes 5 and 6 of the electron-emitting device 74 through the terminals outside the container Dox1 to Doxm and Doy1 to Doyn, and the electron-emitting portion 3 is Thin film 4 for forming electron emission portion
Was manufactured by conducting an energization process (forming process).

In the electron-emitting portion thus produced, fine particles containing palladium as a main component were dispersed and arranged, and the average particle diameter of the fine particles was 30Å.

Next, at a vacuum degree of about 10 ^-6 Torr, an exhaust pipe (not shown) was heated by a gas burner to be welded to seal the envelope. Finally, a getter process was performed to maintain the degree of vacuum after sealing. Immediately before sealing, a getter placed at a predetermined position (not shown) in the image forming apparatus was heated by a heating method such as high-frequency heating to form a vapor deposition film. The getter was mainly composed of Ba or the like.

In the image forming apparatus completed as described above, each of the electron-emitting devices has terminals outside the container Dox1 to Dx.
Electrons are emitted by applying a scanning signal and a modulation signal through signal generators (not shown) through oxm, Doy1 to Doyn, and through the high voltage terminal Hv.
An image was displayed by applying a high voltage of several kV or more to the metal back 85, accelerating the electron beam, causing the electron beam to collide with the fluorescent film, and exciting and emitting light. Compared with the conventional structure, the image forming apparatus manufactured in this manner has no step in the element in the lower wiring direction due to the upper wiring when the electron emission thin film is formed by using the LB method, as compared with the conventional structure. The film thickness distribution is improved, and variations in characteristics of the device are reduced.

The above-described structure is a schematic structure necessary for producing a suitable image forming apparatus used for display or the like, and the detailed parts such as the material of each member are limited to the above contents. However, it can be appropriately selected depending on the purpose of the image device.

[0038]

In the electron source substrate of the present invention, the upper wiring and the contact hole are formed at positions separated from each other, and the contact hole is continuous with the element in the direction intersecting with the lower wiring.
In the surface conduction electron-emitting devices arranged in a matrix, the variation in the characteristics of each device after energization forming has been reduced compared to the conventional one due to the reduction in the film thickness distribution of the thin film for forming the electron-emitting region. You can

Further, according to the idea of the present invention, it is not limited to a suitable image forming apparatus used for display, but an alternative light emitting source such as a light emitting diode of an optical printer including a photosensitive drum and a light emitting diode. As the above, the above-mentioned image forming apparatus can be used. In this case, by appropriately selecting the above-mentioned m row-directional wirings and n column-directional wirings, the present invention can be applied not only to a linear light emitting source but also to a two-dimensional light emitting source.

[Brief description of the drawings]

FIG. 1 is a diagram of an image forming apparatus according to a second exemplary embodiment.

FIG. 2 is a perspective view showing an example of an embodiment and a structure of an electron-emitting device of the present invention.

FIG. 3 is an example of an embodiment and is an example of a process chart for forming an electron emission thin film of the present invention.

FIG. 4 is a plan view of a conventional surface conduction electron-emitting device.

FIG. 5 is a diagram showing one of conventional surface conduction electron-emitting devices arranged in a matrix.

[Explanation of symbols]

1 Insulating Substrate 3 Electron Emitting Part 4 Thin Film Including Electron Emitting Part 5, 6 Element Electrode 11 Insulating Substrate 50 Insulating Layer 51 Insulating Substrate 52, 53 Element Electrode 54 Electron Emitting Section 59 Element Wiring Electrode 72 X Direction Wiring (Bottom Wiring) 73 Y direction wiring (upper wiring) 74 Surface conduction electron-emitting device 75 Connections 76, 77 Device electrode 81 Rear plate with the electron source 1 fixed 82 Support frame 83 Glass substrate 84 Fluorescent film 85 Metal back 86 Face plate 88 Outside Envelope 111 Interlayer insulating layer 112 Contact hole 113 Contact hole that is continuous for elements in the upper wiring direction 114 Connection portion that fills the contact hole portion

Claims (4)

[Claims] 1. An electron source substrate having a large number of surface conduction electron-emitting devices arranged in a matrix on an insulating substrate, wherein an upper wiring and a contact hole are formed apart from each other, and the contact hole is formed as a lower wiring. An electron source substrate, characterized in that it is connected to an element in a direction intersecting with. 2. The electron source substrate according to claim 1, wherein the electron source substrate has a thin film including an electron emitting portion formed by the Langmuir-Blodgett method. 3. A method according to claim 1, wherein: a. After cleaning the insulating substrate, a lower wiring is formed of a conductive material on the substrate by a vacuum process, a photolithography process, or a printing process, b. Forming an insulating film as an interlayer insulating layer by a vacuum vapor deposition method, a printing method or a sputtering method, c. a. A photoresist pattern for forming a contact hole is formed so that each element portion is continuous in a direction intersecting with the lower wiring formed in 1., the interlayer insulating layer is etched using this as a mask, and d. Forming an element electrode on the interlayer insulating layer, e. Forming a connection portion for filling the contact hole, and a.
Forming the upper wiring in the same manner as in f. A conductive thin film is deposited by the Langmuir-Blodgett method to deposit an organometallic complex or a mixture of an organometallic complex and an amphipathic material, and baked to form an electron emitting thin film. Production method. 4. An image forming apparatus formed by the electron source substrate according to claim 1.