JP2004186014A - Manufacturing method for field electron emission type display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a carbon-based material electron emission type display using a cathode base substrate structure capable of withstanding a growth process of a carbon-based electron emission material with a heat cycle from room temperature to 700 °C when directly manufacturing a carbon-based electron emission element in a cathode base substrate. <P>SOLUTION: In this manufacturing method for a field electron emission type display of a 3 pole structure type, a catalyst metal layer 27 is formed only within a gate hole 26 of a gate electrode layer 24 and an insulating layer 23 is formed at a temperature of 300 °C or higher. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a display device using a carbon-based material as an electron emission source. In particular, a method of manufacturing a three-electrode field emission display (FED) comprising a cathode electrode, a gate electrode, and an anode electrode using a carbon-based material such as graphite nanofiber or carbon nanotube. It is about.
[0002]
[Prior art]
Recently, several reports have been made on a method of manufacturing a display device such as an FED using a carbon-based material such as graphite nanofiber or carbon nanotube as an electron emission source.
[0003]
In a display device using an electron emission source, there are cases in which a two-electrode structure element including only a cathode electrode and an anode electrode and a three-electrode structure element including a cathode electrode, a gate electrode, and an anode electrode are used. is there. For example, as shown schematically in FIG. 1, the three-electrode structure type element includes a glass substrate 1, a cathode electrode layer 2, an insulating layer 3, and a gate electrode layer 4, and the gate electrode layer 4 and the insulating layer 3 There is a proposal in which a carbon-based electron-emitting material 5 is provided at the bottom of a gate hole opened at the same time (for example, see Patent Document 1). In this case, a microcavity is formed in the insulating layer at the opening formed in the gate electrode layer by etching using the gate electrode layer as a mask, and then a sacrifice layer (separation layer) is formed.
[0004]
In a three-pole element, the effective electric field applied to the electron emission source can be increased by reducing the distance between the cathode and the gate electrode. Can be lowered. Considering the fact that the FED is actually manufactured and driven, it is desirable that the driving voltage is low. At present, the structure of the FED mainly uses a three-pole element.
[0005]
In a display device having a three-electrode structure type, there are roughly two types of methods for manufacturing a carbon-based electron-emitting device. One is a coating method by a spin coating method, a spray method, a printing method, or the like, and the other is a method of directly forming on a cathode base substrate using a CVD technique or the like. In the latter method, when the carbon-based electron-emitting material is grown on the cathode base substrate, the substrate is exposed to a process temperature of about 400 to 700 ° C., so that the cathode base can withstand a thermal cycle of room temperature to 700 ° C. A substrate structure is required.
[0006]
[Patent Document 1]
JP 2001-236879 A (Claims, FIG. 9, etc.)
[0007]
[Problems to be solved by the invention]
There are the following two problems in the related art when manufacturing an FED.
(1) When a carbon-based electron-emitting material is grown on a substrate, if the substrate is a cathode base substrate on which a catalytic metal layer is continuously present, a portion at the bottom end of a gate hole opened in the gate electrode layer As a result, the carbon-based electron-emitting material penetrates into the portion below the insulating layer and grows, and destroys the structure of the gate hole during the growth process.
(2) The insulating layer of the cathode base substrate is broken by a thermal cycle from room temperature to 700 ° C.
[0008]
An object of the present invention is to provide a method of fabricating an FED that solves the above-mentioned problems of the related art when fabricating a carbon-based electron-emitting device directly in a cathode base substrate. It is an object of the present invention to produce a cathode base substrate structure that can withstand a carbon-based electron-emitting material growth process having the above structure, and to provide a method for manufacturing a field emission display device using this substrate structure.
[0009]
[Means for Solving the Problems]
The method of manufacturing a field emission display according to the present invention is directed to a three-electrode structure electrode layer including a cathode electrode, a gate electrode, and an anode electrode, an insulating layer, a catalyst metal layer, and an electron emission source including a carbon-based material. Wherein the catalyst metal layer is formed only in the gate hole of the gate electrode, and the insulating layer is formed at a temperature of 300 ° C. or higher.
[0010]
By performing the insulating layer forming process at a high temperature of 300 ° C. or more, a cathode base substrate that can withstand the growth process of a carbon-based electron-emitting material having a thermal cycle of room temperature to 700 ° C. can be provided. The problem of destruction of the insulating layer can be solved, and a three-electrode FED using a carbon-based material as an electron emission source can be manufactured.
This catalytic metal layer is formed of Fe, Co, or an alloy containing at least one of these metals.
[0011]
The method for manufacturing a field emission display according to the present invention also includes a three-electrode structure electrode layer including a cathode electrode, a gate electrode, and an anode electrode, an insulating layer, a catalyst metal layer, and an electron emission layer including a carbon-based material. A cathode electrode layer, an insulating layer, and a gate electrode layer are sequentially formed on a glass substrate, and patterning and etching are performed on the gate electrode layer to form a gate hole. After forming an opening, a sacrificial layer is formed on the patterned gate electrode layer, and then a gate hole is formed by etching, and the catalytic metal layer is formed only at the bottom in the gate hole. And
In this case, the formation temperature of the insulating layer is 300 ° C. or higher, and the catalytic metal layer is Fe, Co, or an alloy layer containing at least one of these metals.
[0012]
【Example】
Hereinafter, as an example of the present invention and a comparative example, a method of manufacturing a three-electrode FED using a carbon-based material will be described with reference to the drawings.
(Example 1)
In this embodiment, (1) the catalyst metal layer in the gate hole on the cathode base substrate is formed by using a lift-off method, and (2) the insulating layer between the gate and the cathode electrode is formed by a sputtering method. The insulating layer was formed using an evaporation method, a CVD method, or the like. In this insulating layer forming process, the substrate was heated to 300 ° C. or higher.
FIGS. 2A to 2F are schematic cross-sectional views of a substrate for describing each process in a method of manufacturing a cathode base substrate using a lift-off method.
[0013]
As shown in FIG. 2A, a cathode electrode layer 22, an insulating layer 23, and a gate electrode layer 24 were sequentially formed on a glass substrate 21. The manufacturing conditions are described below. Here, when the substance A is laminated with a film thickness of X nm, it is referred to as A (X nm). As the cathode electrode layer 22, Cr (100 nm) was formed using DC sputtering while heating the substrate at 200 ° C. After patterning of the Cr cathode electrode layer 22 by photolithography, an insulating layer 23 was formed thereon. The insulating layer 23 was formed of SiO ₂ (3 μm) using RF sputtering while heating the substrate at 300 ° C. This is to prevent the insulating layer after film formation from being damaged by stress. At the time of forming the insulating layer, in order to prevent pinholes due to dust adhering to the substrate at the time of the RF sputtering, the SiO ₂ film was formed in _two steps of 1.5 μm, and SiO ₂ (1.5 μm) was formed. Thereafter, rubbing was performed with pure water. Finally, Cr (300 nm) was formed as the gate electrode layer 24. The Cr film was formed by DC sputtering while heating the substrate at 200 ° C. in the same manner as in the case of the cathode electrode layer 22.
[0014]
As shown in FIG. 2B, patterning of the Cr gate electrode layer 24 and etching for forming a gate hole opening were performed. In this embodiment, etching was performed so that the hole diameter of the gate hole opening became 10 μm.
As shown in FIG. 2C, a sacrifice layer (photoresist layer) 25 for protecting portions other than the gate hole was formed on the patterned Cr gate electrode layer 24 by using a photolithography method. .
As shown in FIG. 2D, the SiO ₂ insulating layer 23 was etched using hydrofluoric acid as an etchant to form a gate hole 26. Since the etching is performed after the sacrifice layer 25 is formed, the gate electrode layer is protected.
[0015]
As shown in FIG. 2E, an Fe ₅₂ Ni ₄₂ Cr ₆ layer, which is an Fe alloy, was formed as the catalyst metal layer 27 by RF sputtering. It can also be formed by other film formation methods such as vapor deposition other than sputtering.
As shown in FIG. 2F, the sacrifice layer 25 and the catalyst metal layer 27 on the sacrifice layer were removed.
[0016]
On the cathode base substrate formed by the above process, a carbon-based electron-emitting material is grown on the catalytic metal layer 27 in the gate hole 26 at 400 to 700 ° C. using a thermal CVD method to form a three-electrode structure. Type field emission display device was manufactured. When a gate voltage and an anode voltage were applied to the thus-produced field emission display, stable three-pole current-voltage characteristics were obtained. FIG. 3 shows a photograph of a cross section of the cathode base substrate of the manufactured field emission display device observed by a scanning electron microscope. As is apparent from this figure, the insulating layer was not destroyed even in the thermal cycle in the process of forming the carbon-based electron-emitting material.
Further, the formation of the insulating layer was carried out in the same manner as described above while changing the substrate temperature (350 ° C.), and the formation process of the carbon-based electron emitting material was also performed on the cathode base substrate of the obtained field emission display. The insulating layer was not destroyed by the heat cycle in.
[0017]
(Comparative Example 1)
According to the process conditions of the first embodiment, as shown in FIG. 4, a cathode base substrate in which a catalytic metal layer 43 continuously exists between a cathode electrode layer 42 and an insulating layer 44 formed on a glass substrate 41 Was prepared. In FIG. 4, reference numeral 45 denotes a patterned gate electrode layer, and reference numeral 46 denotes a carbon-based electron-emitting material. Using this cathode base substrate, a field emission display was manufactured. Observation of the cross section of the obtained display device with a scanning electron microscope revealed that when the carbon-based electron-emitting material 46 was grown on this substrate, the carbon-based electron-emitting material 46 was insulated from the portion A at the end of the gate hole. 44, it was found that the structure of the gate hole was destroyed during the growth process.
[0018]
(Comparative Example 2)
A cathode base substrate was manufactured according to the process conditions of Example 1. However, the temperature of the substrate at the time of forming the insulating layer was lower than 300 ° C. (200 to 250 ° C.). A carbon-based electron-emitting material was grown on the prepared cathode base substrate, and a cross section of the cathode-based substrate was observed with a scanning electron microscope. It was found that the insulating layer of the cathode base substrate had been destroyed by the heat cycle of about 700 ° C. (FIG. 5).
[0019]
【The invention's effect】
When growing a carbon-based electronic material on a substrate, if the catalyst base layer is a continuous cathode base substrate, the carbon-based electron-emitting material penetrates from the edge of the gate hole to the portion below the insulating layer. It grows and destroys the gate hole structure during the growth process.
On the other hand, according to the present invention, the catalyst metal layer is formed only in the gate hole of the gate electrode layer, and the insulating layer is formed at a temperature of 300 ° C. or more, thereby destroying the structure of the gate hole. And a cathode base substrate capable of withstanding a process of growing a carbon-based electron-emitting material having a thermal cycle from room temperature to 700 ° C., and using this substrate, a useful three-electrode structure using a carbon-based electron-emitting material as an electron-emitting source The field-emission display device of this type can be manufactured.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a conventional cathode base substrate for a three-electrode FED.
FIGS. 2A to 2F are views showing a procedure for manufacturing a cathode base substrate by a lift-off method according to the manufacturing method of the present invention, and FIGS. 2A to 2F are schematic cross-sectional views of the substrate in each process.
FIG. 3 is a scanning electron micrograph of a cross section of a cathode base substrate for a three-electrode FED manufactured by a lift-off method according to Example 1.
FIG. 4 is a schematic cross-sectional view of a cathode base substrate for a three-electrode FED manufactured in Comparative Example 1.
FIG. 5 is a scanning electron micrograph of a cross section of a cathode base substrate for a three-electrode FED manufactured in Comparative Example 2.
[Explanation of symbols]
Reference Signs List 2 cathode electrode layer 3 insulating layer layer 4 gate electrode layer 5 carbon-based electron emitting material 22 cathode electrode layer 23 insulating layer 24 gate electrode layer 25 sacrificial layer 26 gate hole 27 catalytic metal layer 42 cathode electrode layer 43 catalytic metal layer 44 insulating layer 45 gate electrode layer 46 carbon-based electron emitting material

Claims (5)

In a method of manufacturing a field emission display device including a three-electrode structure electrode layer including a cathode electrode, a gate electrode, and an anode electrode, an insulating layer, a catalyst metal layer, and an electron emission source made of a carbon-based material. Forming the catalytic metal layer only in the gate hole of the gate electrode, and forming the insulating layer at a temperature of 300 ° C. or higher. 2. The method according to claim 1, wherein the catalytic metal layer is formed of Fe, Co, or an alloy containing at least one of these metals. In a method of manufacturing a field emission display device including a three-electrode structure electrode layer including a cathode electrode, a gate electrode, and an anode electrode, an insulating layer, a catalyst metal layer, and an electron emission source made of a carbon-based material. A cathode electrode layer, an insulating layer, and a gate electrode layer are sequentially formed on a glass substrate, and the gate electrode layer is patterned and etched to form an opening of a gate hole, and then the patterned gate electrode layer is formed. A method for manufacturing a field-emission display device, comprising: forming a sacrificial layer thereon, forming a gate hole by etching, and forming the catalyst metal layer only on the bottom of the gate hole. 4. The method for manufacturing a field-emission display device according to claim 3, wherein the insulating layer is formed at a temperature of 300 ° C. or higher. 5. The method according to claim 3, wherein the catalyst metal layer is formed of Fe, Co, or an alloy containing at least one of these metals.

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