JP2012156035A - Electron emission element, electron beam device, image display device and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron emission element which has an insulating member which is disposed on a substrate and has at least one side surface portion rising from the surface of the substrate, a gate provided to the upper surface of the insulating member, a recess portion formed just below the gate of the side surface portion, and a cathode which projects upwards from the lower edge of the recess portion and has a projecting portion having plural apex portions formed in the length direction of the lower edge, and is enhanced in electron emission characteristic.SOLUTION: A cathode 6 is formed by using a first conductive material layer 6a formed by a sputtering method under a full pressure lower than 1.0 Pa, a second conductive material layer is formed by a sputtering method under a full pressure from 1.0 Pa to 2.8 Pa, the second conductive material layer is etched, and an auxiliary apex portion 9 is formed by using the second conductive material layer left on the inner slant surface of the apex portion 8 of the projecting portion, thereby increasing the number of electron emission points.

Description

  The present invention relates to a field emission type electron-emitting device, an electron beam device using the electron-emitting device, an image display device using the electron beam device, and a manufacturing method thereof.

  Conventionally, an electron-emitting device disclosed in Patent Document 1 is known as a field-emission electron-emitting device. That is, the electron-emitting device disclosed in Patent Document 1 includes an insulating member that is disposed on a substrate and has at least one side surface that rises from the surface of the substrate, and a gate that is provided on the upper surface of the insulating member. Yes. A concave portion is formed immediately below the gate in the side surface portion, and a cathode having a protruding portion protruding upward from the lower edge of the concave portion is provided. Patent Document 1 discloses that the protrusions of the cathode have a height distribution, and uniform electron emission by adjusting the distance between the protrusions having the height distribution and the gate. It is disclosed that a characteristic electron-emitting device can be obtained.

JP 2010-262892 A

  The electron-emitting device as shown in Patent Document 1 has a plurality of top portions because the protrusion has a height distribution, and the electric field tends to concentrate on the top portions, so that electrons are emitted from the top portions. become. Therefore, good electron emission characteristics can be obtained by appropriately adjusting the distance between the top of the protrusion and the gate.

  However, for example, in order to obtain an image display device with higher performance, further improvement in electron emission characteristics is required. However, there is a limit to improvement in electron emission characteristics only by adjusting the distance between the top of the protrusion and the gate. There is a problem that cannot be met.

  The present invention has been made in view of the above-described conventional problems. An electron-emitting device including a gate and a cathode having a protrusion facing the gate, the protrusion having a plurality of apexes, further electrons. The purpose is to improve the release characteristics. In addition, another object is to obtain an electron source device and an image display device with good performance.

  According to a first aspect of the present invention, there is provided an insulating member disposed on a substrate and having at least one side surface rising from the surface of the substrate, a gate provided on an upper surface of the insulating member, and the gate of the side surface portion. In a method of manufacturing an electron-emitting device, comprising: a concave portion formed immediately below; and a cathode having a plurality of top portions protruding upward from a lower edge of the concave portion and having a plurality of top portions formed in a length direction of the lower edge. After the cathode is formed with the first conductive material layer formed by a sputtering method under a pressure lower than 1.0 Pa in total pressure, a patterning method under a pressure of 1.0 Pa to 2.8 Pa in total pressure A second conductive material layer is formed at least on the protrusions by etching, and the second conductive material layer is etched so that the second conductive material layer is left on the inner slope of the top of the protrusions. Characterized by forming the top There is provided a method of manufacturing an electron-emitting device.

  The second aspect of the present invention provides a method for manufacturing an electron beam apparatus using the electron emitting element manufactured by the above method for manufacturing an electron emitting element, and the third aspect of the present invention is a method for manufacturing the electron beam apparatus. The present invention provides a method of manufacturing an image display device using the manufactured electron beam apparatus.

  According to a fourth aspect of the present invention, there is provided an insulating member that is disposed on the substrate and has at least one side surface rising from the surface of the substrate, a gate provided on the upper surface of the insulating member, and a portion of the side surface portion directly below the gate. In the electron-emitting device, the protrusion includes a recess formed in the recess, and a cathode that protrudes upward from the lower edge of the recess and has a plurality of apexes formed in the length direction of the lower edge. An electron-emitting device characterized in that a sub-top is formed on the inner slope of the top.

  A fifth aspect of the present invention provides an electron beam apparatus using the electron-emitting device, and a sixth aspect of the present invention provides an image display apparatus using the electron beam apparatus.

  The electron-emitting device according to the present invention is such that a sub-top is formed on the inner slope of the top formed on the projection of the cathode. This sub-top portion forms a convex portion where electrolysis tends to concentrate together with the top portion, and serves as an electron emission point. For this reason, the electron-emitting device according to the present invention has an electron emission point that is increased by the number of sub-tops, as compared with an electron-emitting device having only the top, which does not have a sub-top, and has improved electron emission characteristics. Become.

  On the other hand, according to the manufacturing method of the present invention, the second conductive material layer is formed by sputtering under a total pressure higher than that of the first conductive material layer. In contrast, it can be in a state where it is more easily etched. For this reason, the etching process which removes a 2nd conductive material layer is possible, suppressing melt | dissolution of the cathode formed with the 1st conductive material layer. By the way, among the gaps between the projections of the cathode and the gates, the gaps between the tops of the projections and the gates are particularly narrow, and the inner slopes of the tops are difficult to etch. As a result, when etching the second conductive material layer, the second conductive material layer can remain on the inner slope of the top to form a sub-top, increasing the electron emission point and increasing the emission current. Can do. In addition, when the sub-top portion is formed, the distance from the gate can be easily controlled as a preferable distance as an electron emission point, and as a result, the uniformity of the electron-emitting device can be improved.

  When an electron beam device is configured using the electron-emitting device of the present invention or the electron-emitting device obtained by the manufacturing method of the present invention, the electron beam device is configured using the electron-emitting device having excellent electron-emitting characteristics as described above. Therefore, an electron beam apparatus with excellent performance can be manufactured. Further, when an image display apparatus is configured using the electron beam apparatus of the present invention, an image display apparatus with better performance can be obtained.

It is a schematic diagram which shows an example of the electron emission element which concerns on this invention, (a) is a top view, (b) is AA sectional drawing in (a), (c) is a front view. FIGS. 2A and 2B are partially enlarged schematic views of the electron-emitting device shown in FIG. 1, in which FIG. 1A is an enlarged sectional view around a concave portion, FIG. 1B is an enlarged front view around the concave portion, and FIG. . It is explanatory drawing which shows an example of the process of the manufacturing method of the electron emission element which concerns on this invention, The left side is sectional drawing, The right side is a front view. It is explanatory drawing which shows an example of the process of the manufacturing method of the electron emission element which concerns on this invention, The left side is sectional drawing, The right side is a front view. It is explanatory drawing which shows an example of the process of the manufacturing method of the electron emission element which concerns on this invention, The left side is sectional drawing, The right side is a front view. It is a graph which shows the relationship between the pressure at the time of film-forming (film-forming pressure), and the density of the film | membrane obtained. FIG. 4 is a schematic diagram of crystal grain portions and crystal grain boundary portions in a conductive film, where (a) shows a case where the film is formed under a low pressure, and (b) shows a case where the film is formed under a high pressure. It is a graph which shows the relationship between the etching time and the etching amount about the electroconductive film which changed the total pressure at the time of sputtering. It is a graph which shows the change of the standard deviation (sigma) of the etching time and the space | interval d about the electroconductive film which changed the total pressure at the time of sputtering. It is explanatory drawing of the change when the 1st electrically-conductive material layer of Mo is etched. It is explanatory drawing of the change at the time of the etching of a 2nd conductive material layer. It is explanatory drawing of the measuring system of an electron beam apparatus and an electron emission characteristic. It is explanatory drawing of a display panel, an image display apparatus, and a television apparatus.

  Hereinafter, exemplary embodiments will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent. In the drawings described below, the same reference numerals denote the same components.

  First, an example of the electron-emitting device according to the present invention will be described with reference to FIGS. The electron-emitting device includes an insulating member 3 stacked on the surface of the substrate 1 and a gate 5 provided on the upper surface of the insulating member 3 so as to sandwich the insulating member 3 between the substrate 1 and the insulating member 3. . In the gate 5 of this example, the conductive material layer 4 for the gate 5 laminated on the insulating member 3 and the first conductive material layer 6a for the cathode 6 are integrally formed. The insulating member 3 includes a first insulating material layer 3a and a second insulating material layer 3b that are sequentially stacked. The insulating member 3 has at least one side part rising from the surface of the substrate 1, and the side part of the second insulating material layer 3b constituting the side part of the insulating member 3 is retracted by etching, A recess 7 is formed immediately below the gate 5. Further, the cathode 6 formed of the first conductive material layer 6a is provided on the side surface portion of the first insulating material layer 3a constituting the side surface portion of the insulating member 3. The tip of the cathode 6 protrudes upward from the lower edge of the recess 7 and is a protrusion having a plurality of peaks (peaks) 8 formed in the length direction of the lower edge of the recess 7. A sub-top portion 9 formed of the second conductive material layer 6b is provided on the inner slope of the top portion 8 (the slope facing the inner side of the recess 7).

  The electron-emitting device applies a voltage between the cathode 6 and the gate 5 such that the potential of the gate 5 is higher than the potential of the cathode 6, thereby providing a plurality of top portions 8 and sub-top portions 9 of the cathode 6. Electrons are emitted from the field. In the present invention, the electron emission point is increased by providing the sub-top part 9 on the inner slope of the top part 8 together with the top part 8 functioning as an electron emission point, so that the emission current reaching the anode can be increased. . A gap d ′ is formed between the first conductive material layer 6a constituting the gate 5 and the sub-top 9 as shown in FIG. In particular, the formation of the sub-top portion 9 can be easily controlled to a distance d ′ preferable as an electron emission point, and as a result, the uniformity of the electron-emitting device can be improved.

  In addition, the arrangement position of the gate 5 is not limited to the form shown in FIGS. That is, the cathode 6 may be arranged at a predetermined interval so that an electric field capable of field emission can be applied to the plurality of top portions 8 and sub-top portions 9 which are electron emission portions. In addition, the gate 5 in this example is configured by laminating the conductive material layer 4 for the gate 5 and the first conductive material layer 6a for the cathode 6, but may be configured by the conductive material layer 4 alone. it can. Furthermore, although the insulating member 3 in this example is composed of a laminate of the first insulating material layer 3a and the second insulating material layer 3b, the insulating member 3 may be composed of one insulating layer, A plurality of insulating layers as described above can also be used.

  Next, the outline of each step in the method for manufacturing the electron-emitting device will be described with reference to FIGS.

(Outline of process 1)
The first insulating material layer 3a is formed on the surface of the substrate 1, and then the second insulating material layer 3b is laminated on the upper surface of the first insulating material layer 3a. Then, a conductive material layer 4 to be the gate 5 is laminated on the upper surface of the second insulating material layer 3b [FIG. 3 (a)]. The constituent material of the second insulating material layer 3b is such that the amount of etching with respect to an etching solution (etchant) used in step 3 to be described later is larger than that of the first insulating material layer 3a. A material different from the constituent material of the material layer 3a is selected.

(Outline of process 2)
Next, an etching process (first etching process) is performed on the conductive material layer 4, the first insulating material layer 3a, and the second insulating material layer 3b [FIG. 3B]. Specifically, in the first etching process, a resist pattern is formed on the conductive material layer 4 by a photolithography technique or the like, and then the conductive material layer 4, the second insulating material layer 3b, and the first insulating layer 3a. Is a process of etching. By the step 2 of performing the second etching process, the conductive material layer 4 is laminated on the upper surface, and the insulating member 3 having at least one side surface portion is formed. As shown in FIG. 3B, the side surface portion of the first insulating material layer 3a constituting the side surface portion of the insulating member 3 [the first conductive material layer 6a shown in FIG. The inclination angle θ formed by the surface of the substrate 1 and the surface of the substrate 1 is preferably smaller than 90 degrees. The inclination angle θ is more preferably 50 to 60 degrees as will be described later. Furthermore, the angle formed by the side surface portion of the gate 5 above the side surface portion of the insulating member 3 (the surface above the side surface portion of the first insulating material layer 3a) and the surface parallel to the surface of the substrate 1 is as described above. It is preferable to make it smaller than the inclination angle θ.

(Outline of process 3)
Subsequently, an etching process (second etching process) is performed on the second insulating material layer 3b [FIG. 3C]. The second etching process is a process of selectively etching the second insulating material layer 3b. By the step 3 in which the second etching process is performed, the side surface portion of the second insulating material layer 3b is retreated, and the first insulating material layer 3a and the conductive material are directly below the conductive material layer 4 in the side surface portion of the insulating member 3. A recess 7 sandwiched between the layers 4 is formed. By this step 3, a part of the upper surface portion of the first insulating material layer 3 a is exposed in the recess 7. A corner portion between the part of the exposed upper surface portion of the first insulating material layer 3 a and the side surface portion of the first insulating material layer 3 a is the lower edge of the recess 7.

(Outline of process 4)
The first conductive material layer 6a is deposited by sputtering [FIG. 4 (a)]. The deposition of the first conductive material layer 6a is performed by a sputtering method under the condition that the total pressure is 1.0 Pa or less. By forming the film under this total pressure, the first conductive material layer 6a suitable for forming a significant top 8 [see FIG. 4B] can be formed by etching in step 5 described later. . Moreover, it can be set as the 1st conductive material layer 6a which can endure the etching of the process 7 mentioned later. The first conductive material layer 6a is formed so as to extend from the side surface portion of the first insulating material layer 3a to the upper surface of the first insulating material layer 3a exposed in the concave portion 7, and the concave portion 7 is also formed. Protrusions projecting upward from the lower edge are formed. At the same time, it is also deposited on the conductive material layer 4 and the surface of the substrate 1. In this example, the first conductive material layer 6 a on the conductive material layer 4 is integrated with the conductive material layer 4 to form the gate 5. In FIG. 4A, the first conductive material layer 6a on the side surface side of the first insulating material layer 3a and the first conductive material layer 6a on the conductive material layer 4 are separated at the recess 7 portion. In this example, the film is formed so as not to come into contact. However, the film may be formed so that both are in contact with each other.

(Outline of process 5)
Subsequently, at least the first conductive material layer 6a is subjected to an etching process (third etching process) to form the cathode 6 (FIG. 4B). The third etching process is a process whose main purpose is to form a plurality of top portions 8 which are electron emission portions. In the third etching process, the entire exposed surface of the first conductive material layer 6a is exposed to the etching solution. In Step 4, when the first conductive material layer 6a on the side surface side of the first insulating material layer 3a and the first conductive material layer 6a on the conductive material layer 4 are formed so as to be in contact with each other. In this step, a gap is formed between the two. Further, when the first conductive material layer 6a on the side surface side of the first insulating material layer 3a and the first conductive material layer 6a on the conductive material layer 4 are formed in step 4 so as not to contact each other. In this step, the distance d between the two is widened. In step 5, as shown in FIG. 4B, a plurality of top portions 8 are formed along the length direction of the lower edge of the recess 7 in the protrusion protruding upward from the lower edge of the recess 7. . Further, in step 5, the extra constituent material of the first conductive material layer 6a adhering in the recess 7 can be removed.

(Outline of process 6)
A second conductive material layer 6b is deposited from above the cathode 6 so as to cover at least the projections (FIG. 5A). Although the formation of the second conductive material layer 6b will be described later in detail, the second conductive material layer 6b is formed by a sputtering method under a condition where the total pressure is 1.0 Pa or more and 2.8 Pa or less. By forming the film under these conditions, it is possible to form the second conductive material layer 6b suitable for forming a significant sub-top 9 [see FIG. 5B] by etching in step 7 described later. The second conductive material layer 6b is formed so as to extend from the cathode 6 portion on the side surface portion of the first insulating material layer 3a to the protruding portion protruding from the lower edge of the recess 7, and the gate 5 A film is formed on top. FIG. 5A shows an example in which the second conductive material layer 6b on the cathode 6 side and the second conductive material layer 6b on the gate 5 side are in contact with each other. In some cases, the film is formed so as not to contact.

(Outline of process 7)
Subsequently, an etching process (fourth etching process) is performed on the second conductive material layer 6b to form the sub-top portion 9 [FIG. 5B]. The second conductive material layer 6b formed by the sputtering method under the condition where the total pressure is 1.0 Pa or more and 2.8 Pa or less is the first conductive material layer 6b formed by the sputtering method under the condition of 1.0 Pa or less in Step 4. It is more soluble in the etching solution than the conductive material layer 6a. Even after most of the second conductive material layer 6b is dissolved and removed after the etching process, the first conductive material layer 6a can be left as the cathode 6 without being largely etched. In particular, the top 8 formed at the tip of the cathode 6 forms a narrow gap with the gate 5. Among the gaps between the protrusions formed at the tip of the cathode 6 and the gate 5, the gap between the top 8 and the gate 5 is narrower than the other gaps, and the second conductive material layer 6 b on the inner slope of the top 8. Is difficult to dissolve in the etching process, and as a result, it remains to form the sub-top 9.

  Basically, the electron-emitting device shown in FIG. 1 can be manufactured by the steps 1 to 7 described above. Hereinafter, each step will be described in detail.

(Details of process 1)
Step 1 is the stacking step whose outline has been described with reference to FIG. The substrate 1 is a base for supporting the electron-emitting device. Quartz glass, glass with reduced impurity content such as Na, blue plate glass, and the like can be used. Functions necessary for the substrate 1 include not only high mechanical strength but also resistance to alkalis and acids such as dry etching, wet etching, and developer. Moreover, when using for an image display apparatus, since a heating process etc. are passed, the thing with a small difference of a thermal expansion coefficient with the member to laminate | stack is preferable. In consideration of the treatment, a material in which an alkali element or the like from the inside of the glass is difficult to diffuse into the electron-emitting device is preferable.

The material constituting the first insulating material layer 3a and the second insulating material layer 3b is made of a material excellent in workability, for example, silicon nitride (typically Si ₃ N ₄ ) or silicon oxide (typically SiO ₂ ) can be used. The first insulating material layer 3a and the second insulating material layer 3b can be formed by a general vacuum film forming method such as a sputtering method, a CVD method, or a vacuum evaporation method. The thickness of the first insulating material layer 3a is set in the range of several nm to several tens of μm, and is preferably selected in the range of several tens of nm to several hundreds of nm. The thickness of the second insulating material layer 3b is thinner than the first insulating material layer 3a, is set in the range of several nm to several hundred nm, and is preferably selected in the range of several nm to several tens of nm.

  When the recess 7 is formed in step 3 after laminating the first insulating material layer 3a and the second insulating material layer 3b on the substrate 1, the first insulating material is used for the second etching process. The second insulating material layer 3b is set to have a larger etching amount than the layer 3a. Desirably, the ratio of the etching amount between the first insulating material layer 3a and the second insulating material layer 3b is preferably 10 or more, and more preferably 50 or more. In order to obtain such a ratio of etching amounts, for example, the first insulating material layer 3a is formed of a silicon nitride film, and the second insulating material layer 3b is formed of a silicon oxide film, a high phosphorus concentration of PSG, or a boron concentration. A high BSG film or the like may be used. Note that PSG is phosphorus silicate glass and BSG is boron silicate glass.

  The conductive material layer 4 constituting the gate 5 has conductivity, and is formed by a general vacuum film forming technique such as vapor deposition or sputtering. The constituent material of the conductive material layer 4 is preferably a material having high thermal conductivity and high melting point in addition to conductivity. For example, metals such as Be, Mg, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Al, Cu, Ni, Cr, Au, Pt, and Pd, or alloy materials thereof can be used. Carbides, borides and nitrides can also be used. The thickness of the conductive material layer 4 is set in the range of several nm to several hundred nm, and preferably selected in the range of several tens nm to several hundred nm.

(Details of process 2)
Step 2 is a step of performing the first etching process whose outline has been described with reference to FIG. In the first etching process, it is preferable to use RIE (Reactive Ion Etching), in which a material can be precisely etched by irradiating the material with an etching gas. As the gas used for RIE, a fluorine-based gas such as CF ₄ , CHF _3, or SF ₆ is selected when the target member to be processed is a material that produces fluoride. When the target member to be processed is a material that forms a chloride such as Si or Al, a chlorine-based gas such as Cl ₂ or BCl ₃ is selected. Further, it is preferable to add at least one of hydrogen, oxygen, and argon gas to the etching gas in order to obtain a selection ratio with the resist, to ensure the smoothness of the etching surface, and to increase the etching speed.

  In step 2, the basic shapes of the insulating member 3 and the gate 5 shown in FIG. 1 are formed. However, it does not mean that the insulating material 3 and the conductive material layer 4 constituting the gate 5 are not etched at all by various etching processes performed in the process 3 and subsequent steps.

  The inclination angle θ (angle formed by the side surface portion and the surface of the substrate 1) of the side surface portion of the first insulating material layer 3a constituting the side surface portion of the insulating member 3 controls conditions such as gas type and pressure. Can be controlled to a desired value. θ is preferably an angle smaller than 90 degrees. By setting θ to an angle smaller than 90 degrees, as a result, the side surface portion of the conductive material layer 4 can be made to recede from the side surface portion of the first insulating material layer 3a. Further, the inclination angle of the side surface portion of the conductive material layer 4 (angle formed by the side surface portion and a surface parallel to the surface of the substrate 1) is made smaller than the inclination angle θ of the side surface portion of the first insulating material layer 3a. It is preferable. In addition, when θ is drawn from the boundary between the first insulating material layer 3a and the second insulating material layer 3b toward the substrate 1 in the side surface portion of the insulating member 3, the tangent and the substrate 1 It can be expressed by the angle formed by the surface.

(Details of process 3)
Step 3 is a step of performing the second etching process whose outline has been described with reference to FIG. The etching solution in step 3 is selected so that the amount of etching of the first insulating material layer 3a is sufficiently lower than the amount of etching of the second insulating material layer 3b. In the second etching process, for example, when the second insulating material layer 3b is formed of silicon oxide and the first insulating material layer 3a is formed of silicon nitride, buffered hydrofluoric acid (BHF) is used as an etching solution. Use it. BHF is a mixed solution of ammonium fluoride and hydrofluoric acid. Further, when the second insulating material layer 3b is formed of silicon nitride and the first insulating material layer 3a is formed of silicon oxide, a hot phosphoric acid-based etching solution may be used. By this step 3, a pattern having the recesses 7 shown in FIG. 1 is formed. However, this does not mean that the second insulating material layer 3b is not etched at all in the etching process performed after the step 3.

  The depth (distance in the depth direction) of the recess 7 is deeply related to the leakage current of the electron-emitting device. The deeper the recess 7, the smaller the leak current value. However, if the recess 7 is made too deep, problems such as deformation of the gate 5 occur. For this reason, the depth of the recess 7 is practically set to 30 nm or more and 200 nm or less. In addition, the depth of the recessed part 7 can also be called the distance from the edge part of the 1st insulating material layer 3a which is the lower edge of the recessed part 7 to the side part which the 2nd insulating material layer 3b retreated. The shape between the side surface portion and the upper surface portion of the first insulating material layer 3a, which is the lower edge of the concave portion 7, is not limited to the form connected at the corners, but may be the form connected with a predetermined curvature.

(Details of step 4)
Step 4 is a step of forming the first conductive material layer 6a whose outline has been described with reference to FIG. The first conductive material layer 6a is formed by depositing the material constituting the cathode 6 by sputtering. The constituent material of the first conductive material layer 6a may be any material that is conductive and capable of field emission of electrons, and is preferably selected from materials having a high melting point of 2000 ° C. or higher. The constituent material of the first conductive material layer 6a is a work function material of 5 eV or less, and the oxide is preferably a material that can be easily etched. Suitable examples of such materials include metals such as Hf, V, Nb, Ta, Mo, W, Au, Pt, and Pd, or alloy materials thereof. In consideration of performing the etching process in step 5, it is particularly preferable to use Mo or W as the constituent material of the first conductive material layer 6a.

  Film formation of the constituent material of the first conductive material layer 6a by the sputtering method is performed under a total pressure of 2.8 Pa or less. In particular, when the first conductive material layer 6a forms the top portion 8 [see FIG. 4B] by etching in the next step, the sub-top portion 9 [see FIG. 5B] is further etched in step 7. When forming, the cathode 6 needs to be a stable film that can withstand the etching solution even when exposed to the etching solution. For this reason, as the first conductive material layer 6a, a film having a high film density (a large number of crystal grain portions) obtained by performing sputtering under a total pressure of 1.0 Pa or less is used.

  The influence of the total pressure during sputtering on the film quality and etching characteristics will be described. As shown in FIG. 6, when the conductive film was formed by changing the total pressure at the time of sputtering, it was found that the rate of decrease in the film density suddenly decreased at 1.0 Pa. As described above, when the film is formed under a pressure lower than 1.0 Pa, the obtained conductive film has a high film density (the number of crystal grains increases), and when the film is formed under a pressure higher than 1.0 Pa. Decreases the density of the conductive film (the number of crystal grain boundaries increases). FIG. 7 shows a schematic diagram of crystal grain portions and crystal grain boundary portions in a conductive film. There is an etching selectivity between the crystal grain part and the crystal grain boundary part. For this reason, it is considered that when the conductive film is subjected to the etching process in step 5, the crystal grain boundary portion is preferentially etched as compared with the crystal grain portion. As a result, as shown in FIG. 8, there is a large difference in the etching process rate (etching rate) due to the difference in total pressure during sputtering. In the graph, the curve indicated by A-1 indicates the case of a conductive film formed under a total pressure of 1.7 Pa, and the curve indicated by B-1 indicates a conductive film formed under a total pressure of 0.1 Pa. This case is shown. When the deposition pressure is low, the etching rate is slow, and when it is high, the etching rate is fast. This result is obtained when the etching treatment is performed with an etching solution (40 ° C.) of TMAH (tetramethylammonium hydroxide) having a concentration of 0.3 wt%.

  FIG. 9 is a graph showing changes in the distance d (see FIG. 4B) with the lapse of etching time when the total pressure during sputtering is changed. This distance d is the distance between the cathode 6 (first conductive material layer 6a constituting the cathode 6) and the gate 5 (first conductive material layer 6a constituting the upper layer of the gate 5). The horizontal axis represents the etching time, and the vertical axis represents the standard deviation σ of the distance d between the cathode 6 and the gate 5. In FIG. 9, the curve indicated by A-2 shows the case where the first conductive material layer 6a is formed under a total pressure of 1.7 Pa. In the range where the total pressure is 1.0 Pa or more and 2.8 Pa or less. It becomes a curve similar to this A-2. A curve indicated by A-3 shows a case where the first conductive material layer 6a is formed under a total pressure of 3.0 Pa, and is similar to A-3 in a range where the total pressure is higher than 2.8 Pa. It becomes a curve. The curve indicated by B-2 shows a case where the first conductive material layer 6a is formed under a total pressure of 0.1 Pa, and is similar to B-2 in a range where the total pressure is lower than 1.0 Pa. It becomes a curve. According to FIG. 7, when the film is formed in a pressure range represented by A-2 and the total pressure is 1.0 Pa or more and 2.8 Pa or less, depending on the etching time, the film is formed at a pressure different from this pressure range. Compared to a large σ. When the film is formed under a large total pressure of 2.8 Pa or more, represented by A-3, the change in σ becomes more sensitive to the etching time, compared with the case where the film is formed in the other pressure range described above. Thus, the tendency of poor controllability becomes remarkable. This is considered to be because more crystal grain boundaries are formed compared to the case where the film is formed in the pressure range described above, and the maximum value of σ obtained is also higher than that in the case where the film is formed within the pressure range described above. And a small value.

On the other hand, when the film is formed under a total pressure smaller than 1.0 Pa, represented by B-2, the tendency that σ hardly changes even when the etching time in step 5 is increased becomes significant. This is because more crystal grain portions are formed than in the case where the film is formed in the other pressure range described above. The difference between the crystal grain part and the crystal grain boundary part means a difference between the metal and the metal oxide. Taking Mo as an example, metallic Mo exists in the crystal grain portion. On the other hand, in the grain boundary portion MoOx, and Mo oxide such as MoO ₂ are mixed, the MoO ₃ in particular the outermost surface is localized. When an alkaline aqueous solution such as TMAH is used as an etchant, the Mo oxide is easily etched. Etching of the metal Mo does not proceed easily unless the oxidation proceeds due to dissolved oxygen in the liquid. Accordingly, the first conductive material layer 6a constituting the cathode 6 is preferably a conductive film sputtered under a pressure of 1.0 Pa or less, and this film is a stable film that can withstand etching liquid. . However, for the purpose of forming the plurality of top portions 8 which is another function of the first conductive material layer 6 a, the conductive film sputtered under a pressure of 1.0 Pa or less is significant in forming the top portions 8. Etching is substantially not performed. The coping with this problem will be described in the etching process described later.

  In general, XRR, XPS, or the like is used to measure the density and composition of the conductive film, but it may be difficult to measure with an actual electron-emitting device. In such a case, for example, the following method can be adopted as a method for measuring density and composition. That is, the element can be quantitatively analyzed with a high-resolution electron energy loss spectroscopic electron microscope combining TEM (transmission electron microscope) and EELS (electron energy loss spectroscopy), and the density and composition can be calculated. The standard deviation σ of the distance d between the cathode 6 and the first conductive material layer 6a on the gate 5 side is, for example, in SEM, sequentially along the length direction of the gap between the cathode 6 and the gate 5 d can be measured and calculated from a plurality of measured d. About the influence which the total pressure at the time of sputtering has on the film quality and etching characteristics of the conductive film, the same tendency is shown as long as the conductive film is suitable as the first conductive material layer 6a. In addition, if the power during sputtering, the distance between the substrate 1 and the sputtering target, and the like are in a general range, no particular dependency is observed.

As a sputtering gas, argon (Ar) gas, krypton (Kr) gas, xenon (Xe) gas, or the like can be used, and argon gas is particularly preferable from the viewpoint of manufacturing cost. As the sputtering power source, a DC power source, an RF power source with an industrial power source frequency such as 13.56 MHz can be used. The power at the time of sputtering is a value obtained by dividing the discharge power by the area of the target, and the general range can be, for example, 1 W / cm ² or more and 5 W / cm ² or less. Moreover, the distance between the sputtering target and the substrate 1 can be set to, for example, 50 mm or more and 200 mm or less as a general range.

  The first conductive material layer 6a constituting the cathode 6 and the first conductive material layer 6a constituting the upper layer of the gate 5 may be the same material or different materials. However, the first conductive material layer 6a constituting the cathode 6 and the first conductive material layer 6a constituting the upper layer of the gate 5 can be simultaneously formed of the same material because of ease of manufacture and controllability of etching. preferable. These film thicknesses are set in the range of 10 nm to 40 nm, and preferably selected in the range of 15 nm to 30 nm. In this step, the first conductive material layer 6a constituting the cathode 6 and the first conductive material layer 6a constituting the upper layer of the gate 5 may be formed in contact with each other, or formed without contact. You may do it. When formed by contact, a gap can be formed between them by the step 5.

  When forming the electron-emitting device of the aspect shown in FIG. 1, it is necessary to form a protrusion that protrudes upward from the lower edge of the recess 7. For this reason, the first conductive material layer 6a is preferably formed by a directional sputtering method in which the film forming material is supplied from the direction perpendicular to the surface of the substrate 1. In directional sputtering, for example, after setting the angle between the substrate 1 and the sputtering target, a shielding plate is provided between the substrate 1 and the target. In addition, a so-called collimation sputtering method using a collimator that gives directivity to sputtered particles (sputtered atoms or sputtered particles) that are film forming materials is also a category of the directional sputtering method. In this way, only sputtered particles with a limited angle are incident on the film formation surface. Usually, it is preferable to set the incident angle of the sputtered particles with respect to the upper surface portion of the first insulating material layer 3a exposed in the recess 7 to be close to 0 degrees. The incident angle of the sputtered particles with respect to the side surface portion of the first insulating material layer 3a can be adjusted by an inclination angle θ (see FIG. 3B) given to the side surface portion of the first insulating material layer 3a.

(Details of step 5)
The fifth step is a step of performing the third etching process whose outline has been described with reference to FIG. The third etching process may be either dry etching or wet etching, but it is preferable to select wet etching in consideration of the ease of setting the etching selectivity with other materials. The combination of the material of the first conductive material layer 6a and the etchant used for the third etching process is not particularly limited. However, for example, if the material of the first conductive material layer 6a is molybdenum (Mo), it is preferable to use an alkaline solution such as TMAH (tetramethylammonium hydroxide) or aqueous ammonia as the etching solution. Further, a mixture of 2 (2-n-butoxyethoxy) ethanol and alkanolamine can also be used as an etching solution. Furthermore, a mixed solution containing a general oxidizing agent as an etching solution for Mo may be used. It is preferable to use diluted hydrogen peroxide as the mixed solution containing the oxidizing agent. When the material of the first conductive material layer 6a is tungsten (W), it is preferable to use nitric acid, hydrofluoric acid, sodium hydroxide solution, or the like as an etching solution.

As described above, in the etching process of the first conductive material layer 6a in an alkaline solution such as TMAH, the higher the film density of the first conductive material layer 6a, the slower the etching rate. For the first conductive material layer 6a sputtered under a pressure of 1.0 Pa or less formed in step 4, for example, by using a high-concentration TMAH aqueous solution, a significant top portion of the first conductive material layer 6a is obtained. 8 can be formed. FIG. 10 shows a change when the first conductive material layer 6a of Mo is etched. At the initial stage of immersion in the etching solution, Mo oxidation proceeds. First, Mo is oxidized to MoOx, and the volume expansion of the film occurs. Further, the oxidation proceeds, and MoOx is dissolved into the liquid as MoO4 ²⁻ . FIG. 10A is a cross-sectional view and a front view around the recess 7 before etching. FIG. 10B is a cross-sectional view and a front view of the periphery of the recess 7 in the initial stage of etching, and the surface of the Mo first conductive material layer 6a is volume-expanded by oxidation, and the surface is a mixture of Mo and Mo oxide. This shows the state. Further, as shown in FIG. 10B, even in the same Mo film, there are a portion having a low potential and a noble portion in the same Mo film. As shown in FIG. 10C, which is a cross-sectional view and a front view of the periphery of the recess 7 when etching is completed, the base portion of Mo is ionized and dissolved with the progress of etching, and the precious portion remains as it is. That is, as shown in FIG. 10B, a melted portion and a remaining portion are generated in the protruding portion of the first conductive material layer 6 a, and the remaining portions form a plurality of top portions 8.

  As shown in the prior art, the top portion 8 can also be formed while adjusting the height by controlling the sputtering pressure when the first conductive material layer 6a is formed by sputtering. However, it is preferable to form the top portion 8 as described above because a large number of top portions 8 having the same height can be easily formed.

(Details of step 6)
Step 6 is a step of providing the second conductive material layer 6b whose outline has been described with reference to FIG. The second conductive material layer 6b constitutes the sub-top 9 (see FIG. 5B), and the total pressure of the first conductive material layer 6a is within a pressure range of 1.0 Pa to 2.8 Pa. Deposited by sputtering. In this way, the second conductive material layer 6b is formed as shown in FIG. 5A. As will be described in detail later, the sub-top portion 9 is formed by etching. The film thickness of the second conductive material layer 6b is set in the range of 5 nm to 50 nm, and preferably selected in the range of 10 nm to 25 nm. Also, as shown in FIG. 5A, the second conductive material layer 6b is formed on the cathode 6 and the gate 5, and in this example, the second conductive material layer 6b on the cathode 6; The second conductive material layer 6 b on the gate 5 has a contact in the vicinity of the contact recess 7.

  As described above, the conductive film deposited by the sputtering method in the pressure range of 1.0 Pa or more and 2.8 Pa or less has many crystal grain boundary portions and the film density is low. The etching rate is significantly faster than the conductive film formed by sputtering with a total pressure of 1.0 Pa or less, and is 30 to 40 times faster when etching under the same conditions. This is an etching rate that can leave the cathode 6 that is the first conductive material layer 6a described above when the second conductive material layer 6b is etched in the fourth etching process of the next step. Is the ratio. FIG. 5A shows an example in which the second conductive material layer 6b on the cathode 6 and the second conductive material layer 6b on the gate 5 are in contact with each other. However, the second conductive material layer 6b on the cathode 6 and the second conductive material layer 6b on the gate 5 may be formed so as not to contact each other. Further, in order to deposit the second conductive material layer 6 b in a region including the inner slope of the top 8 formed at the tip of the cathode 6, it is preferable to use a directional sputtering method as in Step 4. .

(Details of step 7)
Step 7 is a step of performing the fourth etching process whose outline has been described with reference to FIG. In this step, a fourth etching process is performed on the second conductive material layer 6 b to form the sub-top portion 9. 11A is a cross-sectional view and a front view around the recess 7 in the initial stage of etching, FIG. 11B is a cross-sectional view and a front view around the recess 7 in the middle of etching, and FIG. It is sectional drawing and front view. As shown in FIG. 11 (a) to FIG. 11 (b), the portion of the contact point between the second conductive material layer 6b on the cathode 6 and the second conductive material layer 6b on the gate 5 is etched. In the process, a bridge is formed as a portion that is difficult to be etched. As the etching further proceeds, the second conductive material layer 6b forming the bridge starts to dissolve. The second conductive material layer 6b on the inner slope of the top 8 is hardly dissolved by the etching process, and as a result, can be left as a sub-top 9 as shown in FIG.

  The sub-top portion 9 formed through the bridge described above is located on the surface of the cathode 6 where the distance between the gate 5 and the cathode 6 is narrow. The sub-top portion 9 is formed from the inner slope of the top portion 8 toward the inner side of the oblique recess portion 7. The direction in which the sub-top portion 9 protrudes is the shortest direction from the inner slope of the top portion 8 to the gate 5. If the sub-top portion 9 is etched in step 2 so that the inclination angle θ of the side surface portion of the first insulating layer 3a is as small as 50 to 60 degrees, the gate 5 recedes from the lower edge of the concave portion 7. For this reason, it becomes closer to the lower side of the inner slope of the top 8, and as a result, moves away from the top 8. When the inclination angle θ of the side surface portion of the first insulating layer 3a is close to 90 degrees, the first insulating layer 3a approaches the top portion 8 as a result of being closer to the upper side of the inner slope of the top portion 8. Since it is easier for both the top portion 8 and the top portion 9 to function as electron emission and emission points when the top portion 8 and the top portion 9 are separated from each other, the inclination angle θ of the side surface portion of the first insulating layer 3a is preferably 50 to 60 degrees. In addition, since the receded gate 5 is easily obtained, the inclination angle of the side surface portion of the conductive material layer 4 constituting the gate 5 is preferably smaller than the inclination angle of the side surface portion of the first insulating layer 3a.

  FIG. 11 shows an aspect of the etching process from a state in which the second conductive material layer 6b on the cathode 6 and the second conductive material layer 6b on the gate 5 are sputtered so as to be in contact with each other. However, even when the second conductive material layer 6b on the cathode 6 and the second conductive material layer 6b on the gate 5 are formed so as not to come into contact with each other, at the initial stage of being immersed in the etching solution. It is also possible to generate a contact point by causing volume expansion by oxidizing both.

  Next, the top part 9 of the electron-emitting device formed by the above manufacturing method and its peripheral structure will be described.

  As shown in FIG. 2, the cathode 6 includes a plurality of top portions 8 provided side by side along the length direction of the lower edge of the recess 7. The sub-top 9 is formed at the shortest distance between the inner slope of the top 8 and the gate 5. Then, a plurality of minute projections such as the sub-top portion 9 are arranged in the length direction of the lower edge of the concave portion 7 together with the top portion 8. The top 8 protrudes upward from the lower edge of the recess 7 and protrudes toward an anode 18 (see FIG. 12) described later. On the other hand, the sub-top portion 9 is formed on the inner slope of the top portion 8 of the cathode 6 described above, and the projecting direction of the top portion 10 is directed to the shortest direction with the gate 5.

  In FIG. 2, the first conductive material layer 6 a is illustrated as hanging from the side surface portion of the conductive material layer 4 constituting the gate 5. However, when the first conductive material layer 6 a is thin, The conductive material layer 4 may form a narrow portion with the cathode 6. In this case, the sub-top portion 9 is formed in the closest portion among the narrow portions generated between the inner slope of the top portion 8 and the conductive material layer 4, and the direction in which the sub-top portion 9 protrudes from the conductive material layer 4. That is the direction toward the shortest part.

  A sub-top portion 9 is provided so as to protrude from the inner slope of the top portion 8. The distance between the periphery of the sub-top portion 9 and the gate 5 is larger than the distance between the sub-top portion 9 and the gate 5. Electrons emitted from the sub-top portion 9 are isotropically scattered at the gate 5, but among the scattered electrons, electrons scattered on both sides of the sub-top portion 9 pass through a portion having a wide interval with the gate 5 and become the anode. 18 (see FIG. 12). This is one of the reasons for improving the release characteristics.

  As shown in FIG. 2, when the sub-top portion 9 is enlarged, the tip portion has a shape represented by a curvature radius r. Depending on the radius of curvature r, the electric field strength at the tip changes. As r is smaller, the lines of electric force are concentrated, so that a high electric field can be formed at the tip of the sub-top portion 9. Practically, r is 2 nm or more and 12 nm or less, more preferably 2 nm or more and 5 nm or less. Since the distance d ′ between the gate 5 and the sub-top portion 9 affects the difference in the number of electron scattering at the gate 5, the larger the d ′, the higher the electron emission efficiency. In addition, the amount of emission current can be improved. The drive voltage required to emit electrons becomes too large when d 'is greater than 10 nm. In addition, d ′ is preferably 1 nm or more from the viewpoint of stability during driving. If it is smaller than 1 nm, the sub-top portion 9 may be destroyed during driving due to field evaporation, discharge, short circuit, or the like. Therefore, practically, d ′ is 1 nm or more and 10 nm or less, more preferably 4 nm or more and 8 nm or less. Moreover, it is preferable that the height of the sub-top part 9 is 2 nm or more and 10 nm or less.

  In the conventional electron-emitting device, the top 8 is formed on the cathode, and this top 8 functions as an electron emission point, but the sub-top 9 is further formed on the inner slope of the top 8 by the manufacturing method described above. As a result, the number of electron emission points can be increased. Further, it is possible to form the sub-top portion 9 at the shortest portion between the gate 5 and the top portion 8 of the cathode 6, whereby the distance between the tip of the sub-top portion 9 and the gate 5 is a preferable range of 1 nm to 10 nm. It becomes easy to control. As a result, it is possible to form an electron-emitting device with high electron emission efficiency and a further improved emission current amount. In addition, such an electron-emitting device can be formed in a large area.

  Next, an example of an electron beam apparatus using the electron-emitting device manufactured by the manufacturing method of the present invention will be described with reference to FIG. This electron beam apparatus can also be used as a measuring apparatus for electron emission characteristics of an electron-emitting device. In this electron beam apparatus, the cathode 6 of the electron-emitting device manufactured by the manufacturing method of the present invention is connected to the wiring 2 for driving, and is opposed to the top 8 and the sub-top, and the anode is connected through the gate 5. It can be obtained by arranging 18. In this device, the electron emission efficiency (η), which is the arrival efficiency of electrons emitted from the cathode 6 to the anode 18, is the device current If detected when the electron-emitting device is driven and the anode 18 through the vacuum. It is obtained using the emission current Ie which is the current that reaches. That is, η = Ie / (If + Ie). The electron emission characteristics can be measured with the configuration shown in FIG. In FIG. 12, Vf is a voltage applied between the gate 5 and the cathode 6, and If is an element current flowing between the gate 5 and the cathode 6 when Vf is applied between the gate 5 and the cathode 6. Va is a voltage applied between the cathode 6 and the anode 18, and Ie is an emission current. Although an example in which Va is applied between the cathode 6 and the anode 18 is shown here, a power source that applies a potential to the anode 18 and a power source that applies a potential to the cathode 6 may be provided separately. As shown in FIG. 12, an anode 18 defined at a higher potential than the gate 5 and the cathode 6 is provided above the substrate 1 on which the electron-emitting devices are provided, thereby emitting light from the plurality of top portions 8 and sub-top portions 9. An electron beam apparatus is configured to cause the electrons to reach the anode 18.

  Next, an image display apparatus using the above electron beam apparatus will be described with reference to FIG.

  FIG. 13A is a schematic view showing an example of a display panel 77 configured using an electron source in which electron-emitting devices are arranged in a matrix, and a part thereof is cut away so that the inside can be seen. In FIG. 13A, 61 is an electron source substrate, 62 is an X direction wiring, and 63 is a Y direction wiring. The electron source substrate 61 corresponds to the substrate 1 of the electron-emitting device described above. Reference numeral 64 schematically represents the above-described electron-emitting device group. The X-direction wiring 62 is a wiring that commonly connects the cathodes 6 described above, and the Y-direction wiring 63 is a wiring that commonly connects the gates 5 described above. Here, an example in which the electron-emitting device is provided at the intersection of the X-direction wiring 62 and the Y-direction wiring 63 is shown schematically, but the electron-emitting device is an intersection of the X-direction wiring 62 and the Y-direction wiring 63. Can be provided on the electron source substrate 61 on the side.

  The X-direction wiring 62 is connected to a scanning signal applying unit (not shown) that applies a scanning signal for selecting a row of the electron-emitting devices 64 arranged in the X direction. On the other hand, the Y direction wiring 63 is connected to a modulation signal generating means (not shown) for modulating each column of the electron-emitting devices 64 arranged in the Y direction according to an input signal. The drive voltage applied to each electron-emitting device is supplied as a difference voltage between the scanning signal and the modulation signal applied to the device. In this configuration, individual electron-emitting devices 64 can be selected and driven independently using simple matrix wiring.

  In FIG. 13A, the electron source substrate 61 is fixed to the rear plate 71. Further, on the inner surface of the glass substrate 73, a light emitting body 74 made of, for example, a phosphor that emits light when irradiated with electrons emitted from the electron emitting element, and a metal back 75 corresponding to the anode 18 described above are laminated. The face plate 76 is configured. Further, the rear plate 71 and the face plate 76 are hermetically joined via a support frame 72 provided between the rear plate 71 and the face plate 76 and a joining member such as frit glass, and the display panel 77 is thereby joined. It is configured. The display panel 77 includes the face plate 76, the support frame 72, and the rear plate 71 as described above. Here, since the rear plate 71 is provided mainly for the purpose of reinforcing the strength of the electron source substrate 61, if the electron source substrate 61 itself has sufficient strength, the separate rear plate 71 is not required. Can do. On the other hand, by providing a support (not shown) called a spacer between the face plate 76 and the rear plate 71, it is possible to provide a structure with sufficient strength against atmospheric pressure.

  Next, the image display device 25 and the television device 27 including the display panel 77 will be described with reference to the block diagram of FIG.

  The receiving circuit 20 includes a tuner, a decoder, and the like, receives various signals such as satellite broadcasting and terrestrial television signals, and data broadcasting via a network, and outputs decoded video data to the image processing unit 21. . The above-mentioned “received signal” can be rephrased as “input signal”. The image processing unit 21 includes a γ correction circuit, a resolution conversion circuit, an I / F circuit, and the like. The image processing unit 21 converts the image-processed video data into a display format of a display (image display device) 25 and sends it to the image display device 25 as an image signal. Output.

  The image display device 25 includes at least the display panel 77 described above, and further includes a drive circuit and a control circuit 22 that controls the drive circuit. The control circuit 22 performs signal processing such as correction processing on the input image signal, and outputs the image signal and various control signals to the drive circuit. The control circuit 22 includes a synchronization signal separation circuit, an RGB conversion circuit, a luminance signal conversion unit, a timing control circuit, and the like. The drive circuit outputs a drive signal to the electron-emitting devices inside the display panel 77 based on the input image signal, and a television image is displayed based on the drive signal. The drive circuit includes a scanning circuit, a modulation circuit, a high-voltage power supply circuit that supplies an anode potential, and the like. The receiving circuit 20 and the image processing circuit 21 may be housed in a housing separate from the image display device 25 as a set-top box (STB 26), or in a housing integral with the image display device 25. It may be. Here, an example in which the television device 27 displays a television image has been described. However, if the receiving circuit 20 is a circuit that receives video distributed through a line such as the Internet, the television device 27 functions as a video display device capable of displaying various videos as well as television videos. .

  The electron beam apparatus using the electron-emitting device manufactured according to the present invention uses not only the image display device 25 as described above but also a target that generates X-rays by electron irradiation as the anode 49, so that X-rays can be obtained. An apparatus can also be constructed.

  Hereinafter, more specific examples based on the above embodiment will be described.

Example 1
A method for manufacturing the electron-emitting device of this example will be described with reference to FIGS.

  First, as shown in FIG. 3A, a first insulating material layer 3a, a second insulating material layer 3b, and a conductive material layer 4 are sequentially laminated on the substrate 1. As the substrate 1, high strain point low sodium glass (PD200 manufactured by Asahi Glass Co., Ltd.) was used. As the first insulating material layer 3a, a silicon nitride film was formed by a sputtering method, and the thickness thereof was set to 500 nm. As the second insulating material layer 3b, a silicon oxide film was formed by a sputtering method, and the thickness thereof was 30 nm. As the conductive material layer 4, a tantalum nitride film was formed by a sputtering method, and its thickness was 30 nm.

Next, as shown in FIG. 3B, after a resist pattern is formed on the conductive material layer 4 by a photolithography technique, the conductive material layer 4, the second insulating material layer 3b, The first insulating material layer 3a was processed in order. By this first etching process, the conductive material layer 4 was provided on the upper surface, and the insulating member 3 having a side surface rising from the surface of the substrate 1 was formed. As the etching gas at this time, a CF ₄ -based gas was used because the first and second insulating material layers 3a and 3b and the conductive material layer 4 are made of a material that produces fluoride. As a result of performing RIE using this gas, the inclination angle after etching was 50 to 60 degrees at the side surface portion of the first insulating material layer 3a and about 40 degrees at the side surface portion of the conductive material layer 4.

After removing the resist, as shown in FIG. 3 (c), using BHF (Stella Chemifa Co., Ltd., high-purity buffered hydrofluoric acid LAL100), the depth of the recess 7 is about 70 nm. The insulating material layer 3b was etched. BHF is a mixture of NH ₄ HF ₂ = 0.9 wt% and NF ₄ F = 16.4 wt%. By this second etching process, a recess 7 was formed immediately below the conductive material layer 4 on the side surface of the insulating member 3.

Next, as shown in FIG. 4A, at least a first insulating material is formed on the side surface of the first insulating material layer 3a, the upper surface exposed in the recess 7, and further on the conductive material layer 4. Molybdenum (Mo) was deposited by directional sputtering so that the thickness on the side surface of the layer 3a was 25 nm. Sputtering was performed by setting the surface of the substrate 1 so as to be horizontal with respect to the sputtering target. In this embodiment, a shielding plate is provided between the substrate 1 and the target so that the sputtered particles are incident on the surface of the substrate 1 at a limited angle (specifically, 90 ± 10 ° with respect to the surface of the substrate 1). Provided. The power of argon plasma during sputtering was 1 W / cm ² , the distance between the substrate 1 and the target was 100 mm, and the total pressure was 0.4 Pa. Then, the first conductive material layer 6a was formed such that the amount of the constituent material of the first conductive material layer 6a into the recess 7 [distance X in FIG. 2 (c)] was 35 nm. In this example, the film was formed simultaneously on the side surface portion of the first insulating material layer 3 a and the conductive material layer 4. Further, the pattern of the first conductive material layer 6a was formed by using the photolithography technique and the Mo dry etching method.

  Next, as shown in FIG. 4B, a wet etching process (third etching process) was performed on the first conductive material layer 6a. As the etching solution, a 2.38 wt% TMAH (tetramethylammonium hydride) aqueous solution was used. The first conductive material layer 6a was immersed in this etching solution for 180 seconds, and then washed with running water for 5 minutes. By performing the alkali treatment on the first conductive material layer 6a in this way, a large number of top portions 8 are formed along the length direction of the lower edge of the concave portion 7 at the protrusions of the first conductive material layer 6a. .

  Next, as shown in FIG. 5A, molybdenum (Mo) is deposited on the first conductive material layer 6a as a second conductive material layer 6b by a directional sputtering method so as to have a film thickness of 20 nm. Deposited. Sputtering was performed under a total pressure of 1.7 Pa. The second conductive material layer 6b was formed so that a contact was formed between the second conductive material layer 6b on the cathode 6 side and the second conductive material layer 6b on the gate 5 side. Further, the pattern of the second conductive material layer 6b was formed by using the photolithography technique and the Mo dry etching method.

  Finally, as shown in FIG. 5B, a wet etching process (fourth etching process) was performed on the second conductive material layer 6b. As the etching solution, a TMAH (tetramethylammonium hydride) aqueous solution having a concentration of 0.3 wt% was used. The second conductive material layer 6b was immersed in this etching solution for 60 seconds, and then washed with running water for 5 minutes. By performing the alkali treatment on the second conductive material film 6b in this way, the second conductive material layer 6b remaining on the inner slope of the top portion 8 formed on the protrusion of the first conductive material layer 6a is sub-charged. A top 9 was formed.

  An electron source was produced by arranging the electron-emitting devices obtained in the above steps in a matrix, and a display panel 77 shown in FIG. 13A was produced using the electron source. Specifically, on the rear plate 71 made of a glass substrate, 1080 rows of X-directional wiring (row wiring) 62 and 3 × 1920 columns of Y-directional wiring (column wiring) 63 are made of silver paste. Formed by screen printing. Subsequently, the electron-emitting device 62 was formed in the vicinity of each intersection of the X-direction wiring 62 and the Y-direction wiring 63. On the other hand, 1080 × 3 × 1920 phosphors 74 (1080 rows × 1920 columns of pixels) are formed on the surface of the glass substrate 73, and a metal back 75 made of aluminum is laminated thereon to form a face plate. 76 was formed. Then, in the vacuum chamber, a support frame 72 provided with frit glass in advance is disposed between the rear plate 71 and the face plate 76, and between the rear plate 71 and the support frame and between the face plate 76 and the support frame. And hermetically sealed with frit glass. Thus, an FED display (display panel 77) in which the inside was maintained in a vacuum was formed. Then, when the television device 27 shown in FIG. 13B was formed using the display panel 77, a high-luminance image could be displayed uniformly in the surface.

  The electron emission efficiency η of the electron-emitting device manufactured in this example was 6.2% on average. The variation for each electron-emitting device was 0.9%. Further, when the electron-emitting device formed by the manufacturing method of this example was confirmed by SEM, 15 to 20 protrusions corresponding to the sub-top were formed per 1 μm. In all the protrusions, the distance between the gate and the protrusion tip was included in the range of 1 nm to 10 nm. Further, when a part of these protrusions was observed with a TEM in cross-section, the position and protrusion direction of the protrusions coincided with the shortest distance direction between the position closest to the gate of the top of the cathode where the sub-top was formed and the gate.

(Comparative Example 1)
An electron-emitting device was fabricated in the same manner as in Example 1 except that the second conductive material layer 6b shown in FIGS. 5A and 5B was not formed and etched. When the display panel 77 shown in FIG. 13A is manufactured using this electron-emitting device and the television device 27 is formed, the luminance is inferior to that of the first embodiment and the luminance varies in some areas. It was. When the electron emission efficiency η was measured in the same manner as in Example 1, the average was 5.5%. The variation for each electron-emitting device was 2.1%, which was slightly larger than Example 1.

  Further, when the electron-emitting device formed by the manufacturing method of Comparative Example 1 was confirmed by SEM, it was confirmed by SEM that the protrusion corresponding to the top was formed in the same manner as in Example 1. However, when the cross section was observed with a TEM, there was no minute protrusion corresponding to the sub-top portion observed in Example 1. When the top portion was confirmed in detail, in some of the electron emission portions, the distance between the gate end portion and the protrusion tip was 10 nm or more.

  1: substrate, 2: wiring, 3: insulating member, 3a: first insulating material layer, 3b: second insulating material layer, 4: conductive material layer, 5: gate, 6: cathode, 6a: first Conductive material layer, 6b: second conductive material layer, 7: recess, 8: top, 9: sub-top, 18: anode, 61: electron source substrate, 62: X direction wiring, 63: Y direction wiring, 64: Electron emitting device (group), 71: rear plate, 72: support frame, 73: glass substrate, 74: light emitter, 75: metal back, 76: face plate, 77: display panel, 20: receiving circuit, 21: image Processing unit, 22: control circuit, 25: image display device, 26: set top box, 27: television device

Claims (10)

An insulating member disposed on the substrate and having at least one side surface rising from the surface of the substrate; a gate provided on an upper surface of the insulating member; and a concave portion formed immediately below the gate in the side surface portion. A method of manufacturing an electron-emitting device comprising: a cathode having a protrusion protruding upward from a lower edge of the recess and having a plurality of apexes formed in a length direction of the lower edge;
After the cathode is formed with the first conductive material layer formed by the sputtering method under a pressure lower than 1.0 Pa, the total pressure is measured by a sputtering method under a pressure of 1.0 Pa to 2.8 Pa. A second conductive material layer is formed covering at least the protrusion, and the second conductive material layer is etched, and the second conductive material layer is left on the inner slope of the top of the protrusion. A method for manufacturing an electron-emitting device, characterized by comprising:   The angle of inclination of the side surface of the insulating member is 50 to 60 degrees, and the angle of inclination of the side surface of the gate above the side surface of the insulating member is smaller than the angle of inclination of the side surface of the insulating member. The method for manufacturing an electron-emitting device according to claim 1.   A cathode of an electron-emitting device manufactured by the method for manufacturing an electron-emitting device according to claim 1 or 2 is connected to a wiring, and an anode is disposed so as to face the top and the sub-top through the gate. A method for manufacturing an electron beam apparatus.   4. A method for manufacturing an image display device, comprising: a light-emitting body that emits light when irradiated with electrons, on the anode side of an electron beam device manufactured by the method for manufacturing an electron beam device according to claim 3. An insulating member disposed on the substrate and having at least one side surface rising from the surface of the substrate; a gate provided on an upper surface of the insulating member; and a concave portion formed immediately below the gate in the side surface portion. An electron-emitting device comprising: a cathode having a protrusion protruding upward from the lower edge of the recess and having a plurality of peaks formed in the length direction of the lower edge;
An electron-emitting device, wherein a sub-top is formed on the inner slope of the top of the protrusion.   The angle of inclination of the side surface of the insulating member is 50 to 60 degrees, and the angle of inclination of the side surface of the gate above the side surface of the insulating member is smaller than the angle of inclination of the side surface of the insulating member. The electron-emitting device according to claim 5.   7. The electron-emitting device according to claim 5, wherein a height of the sub-top portion is 2 nm or more and 10 nm or less, and a distance between a tip of the sub-top portion and an end portion of the gate is 1 nm or more and 10 nm or less.   The electron-emitting device according to any one of claims 5 to 7, wherein a constituent material of the cathode including the sub-top is molybdenum or tungsten.   The electron of the electron-emitting device according to any one of claims 5 to 8, wherein a cathode is connected to a wiring, and an anode is disposed so as to face the top and the sub-top through the gate. Wire device.   10. An image display device, wherein a light emitter that emits light when irradiated with electrons is disposed on the anode side of the electron beam device according to claim 9.

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