JP3540705B2 - Method of manufacturing field emission device, field emission device and flat display device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a field emission device, a field emission device, and a flat display device. In particular, in addition to a method for directly shaving an emitter shape, an emitter-like emitter shape is formed on a mold master used in a transfer molding method. About things.
[0002]
[Prior art]
In recent years, with the progress of semiconductor fine processing technology, a field emission device, which is a micro vacuum tube (electron gun) having a micron size, has attracted attention and its development has been promoted.
[0003]
This field emission device is considered to be used as an electron emission source for electron beam lithography systems and flat displays. For this purpose, it is necessary to arrange a number of sharpened emitter electrodes at high density in the plane direction. There is. Further, when used as an electron emission source for a flat display, it is necessary to improve the sharpness of the emitter electrode to lower the drive voltage of each element.
[0004]
[Problems to be solved by the invention]
The conventional method of manufacturing the above-described field emission device has the following problems. That is, the sharpening of the emitter electrode is performed by a technique such as overlay exposure or anisotropic etching which is used as a semiconductor manufacturing technique. For this reason, the reproducibility of the process of sharpening the emitter electrode is poor, and it has been difficult to uniformly form a large number of emitter electrodes.
[0005]
In this case, the sharpness depends on the resolution of the exposure apparatus. That is, the sharpness of the emitter electrode depends on the resolution of a stepper or the like that performs mask patterning. However, since the resolution is limited, the sharpening has a certain limit.
[0006]
Further, the method of forming a field emission device using a semiconductor manufacturing technique has a problem that the size of a substrate on which the device is formed is limited to the size of a semiconductor wafer.
[0007]
Therefore, an object of the present invention is to provide a method of manufacturing a field emission device having fine, high density and high shape accuracy, a field emission device, and a flat display device.
[0008]
[Means for Solving the Problems]
In order to solve the above problems and achieve the object, a method for manufacturing a field emission device, a field emission device, and a flat display device according to the present invention are configured as follows.
[0009]
(1)Substrate made of metalCuttingDMittaelectrodeCharacterized in that it comprises a step of shaving
[0010]
In addition, a single workpiece has an area corresponding to the size of the flat display, and an emitter shape for all the pixels of the flat display may be formed thereon.
[0011]
The step of shaving the emitter shape by cutting may include shaving the emitter shape from the workpiece by forming a plurality of grooves that gradually become narrower as the depth increases, on the surface of the workpiece. Well, furthermore, the step of shaving the emitter shape by cutting is a step of forming a plurality of grooves parallel to the surface of the workpiece and the step of shaping the emitter shape by performing this step a plurality of times with different groove directions And a step. Furthermore, in the step of shaving the emitter shape by cutting, the step of forming a plurality of grooves parallel to the surface of the workpiece is performed a plurality of times by shifting the forming groove direction by 90 degrees, thereby forming a square pyramid-shaped emitter shape. May be formed. Furthermore, in the step of shaving the emitter shape by cutting, the step of forming a plurality of grooves parallel to the surface of the workpiece is performed a plurality of times by shifting the direction of the grooves to be formed by 60 degrees, thereby forming a triangular pyramid. An emitter shape may be formed.
[0012]
The step of shaving the emitter shape by cutting uses a rotating tool having both lateral cutting edges and a front cutting edge that gradually become narrower toward the outer circumferential edge, and rotates the rotating tool and the workpiece. By relatively feeding and driving along the rotational tangential direction of the tool, a groove that gradually becomes narrower in the depth direction may be formed in the workpiece.
[0013]
Alternatively, the emitter shape of the field emission device may be directly formed by shaving the emitter shape on the surface of the workpiece by the above-mentioned cutting process.
[0014]
Furthermore, after cutting with a first tool having a predetermined cutting edge angle, further processing may be performed with a tool having a different cutting edge angle from the first tool. Further, after cutting with a first tool having a predetermined cutting edge angle, further processing may be performed with a tool having a different cutting edge width from that of the first tool.
[0015]
On the other hand, a cylindrical workpiece may be used. In addition, the ridge line forming the emitter shape is non-linear, the line is composed of a plurality of line segments, the one where the inclination of the ridge line is closer to the tip is steep, the one that has a predetermined curve, and the one that has at least one step. There may be.
[0016]
(2) It is formed using a workpiece having an emitter electrode formed by using the method of manufacturing a field emission device described in (1).
[0017]
(2)The step of shaving the emitter electrode described in the above (1) includes: a first cutting step of forming a plurality of grooves gradually narrowing as the depth increases in the surface of the substrate; And a second cutting step of forming a plurality of parallel grooves in which the groove directions are made different and gradually become narrower as the groove becomes deeper.
[0018]
(3) The cutting described in the above (1) is performed using a plurality of cutting tools having different cutting edge angles.
[0019]
(4) An emitter electrode having an apex angle of 30 ° or more and 70 ° or less provided by the method described in the above (1).
[0020]
(5)The emitter electrode described in the above (4) has a shape in which a plurality of line segments or arcs are combined.
[0021]
(6)At least a field emission device provided with an emitter electrode having a ridge line formed by combining a plurality of line segments or arcs and having an apex angle of 30 ° or more and 70 ° or less according to the method described in claim 1. A cathode device having a gate electrode for emitting electrons from the emitter electrode; and a transparent electrode provided with at least a positive electrode for attracting electrons emitted from the cathode device and a luminous film for emitting light when the electrons collide. An anode device having an optical substrate.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
1 to 11 are views showing a method for manufacturing a field emission device according to the first embodiment of the present invention. In the method of manufacturing the field emission device, by cutting the surface layer of the substrate, the emitter shape row (emitter array) of the field emission device is cut out, and a final product such as a flat display device is obtained. Things.
[0023]
FIG. 1 shows an enlarged view of an emitter array 1 (rows of emitter shapes 2) formed by this method. Each emitter shape 2 is a square pyramid having a side length L = 1 to 50 μm, an apex angle θ = 30 to 120 ° (preferably about 70 °), a height H = 1 to 50 μm, and an interval M = 1. ５０50 μm, and the pitch P = 1 to 100 μm.
[0024]
For example, in the case of a field emission element applied to a flat display device (FED: Field Emission Display), the emitter shape 2 is about 5 × 3 (“3” is the number of RGB) and about 10 in a vertical direction per pixel. Assuming that the size of one screen of the FED is about 1000 pixels × about 800 pixels vertically, a total of 15000 × 800 pixels must be formed on the entire screen.
[0025]
This embodiment provides a method for forming a total of 15000 × 800 emitter arrays 1 at a time with the cutting apparatus shown in FIG.
[0026]
This cutting apparatus is a portal NC machine, and a portal head 5 mounted on a base 4 holds a spindle device shown in FIG. 6 in the XYZ directions so as to be freely positioned. The spindle device 6 has a high-speed air spindle (not shown) and a spindle 7 driven to rotate by the air spindle. A diamond bite is attached to the tip of the spindle 7 via a disk-shaped bracket 8. 9 (rotary tool) is attached. The diamond cutting tool 9 is attached so as to protrude outward along the radial direction of the main shaft 7.
[0027]
As shown in FIG. 3, the diamond cutting tool 9 includes a shank 11 fixed to the main shaft 7 and a diamond chip 12 bonded to the tip of the shank 11.
[0028]
FIG. 4 shows the shape of the cutting edge of the diamond tip 12. The diamond chip 12 includes a scooping surface 12a, a front cutting blade 12b, a horizontal cutting blade 12c, a front cutting blade flank 12d, and a horizontal cutting blade flank 12e. Here, the front cutting edge length W and the vertex angle φ of the scooping surface 12a are designed to be equal to the interval M and the vertex angle θ (see FIG. 1) of the emitter shape 2, respectively. Further, the front cutting edge clearance angle α and the horizontal cutting blade clearance angle β are each set to 3 °.
[0029]
Further, as shown in FIG. 2, a substrate 14 as a work object is held on a rotary positioning table 15 on a base 4 of the processing apparatus. The substrate 14 is, for example, a master for manufacturing a mold used when an emitter electrode of a field emission device is formed by a transfer molding method, and has a projection area corresponding to all pixels of the FED. is there.
[0030]
Next, a process of forming the emitter shape 2 on the surface of the substrate 14 will be described with reference to FIGS. 2, 5, and 6A to 6C.
[0031]
First, the portal head 5 shown in FIG. 2 is operated, the main spindle device 6 is driven in the XY directions, and the diamond cutting tool 9 is positioned facing the substrate 14. Next, the diamond cutting tool 9 is rotated by operating the spindle device 6. Thus, the front cutting edge 12b of the diamond tip 12 draws a circular locus indicated by a dotted line γ in FIG.
[0032]
In this state, the spindle device 6 is driven downward in the Z direction to cut the diamond cutting tool 9 into the substrate 14 at a predetermined cutting depth D, and is driven in the X-axis direction at a predetermined feed speed. As a result, as shown in FIG. 5, the surface layer (shaded portion) of the substrate 14 is scraped off on the scooping surface 12a of the diamond chip 12, and a groove 17 having the same cross-sectional shape as the scooping surface 12a of the chip 12 is formed. I can go.
[0033]
Here, the feed amount f (feed speed F) per unit time in the X direction of the spindle device 6 is determined based on the maximum cut thickness t per one time, as shown in FIG. In order to control chipping during processing and to sharpen the tip of the emitter shape 2 to, for example, a tip radius of 30 nm or less, the maximum cut thickness t is set to a certain thickness or less, preferably t ≦ 10 μm, and more preferably t ≦ 1 μm. Need to be controlled.
[0034]
Here, t is S, the rotation speed of the diamond cutting tool 9, the tool feed speed is F (= f · dx / dt), the cutting depth is D, and the turning radius of the cutting tool is R. From the scientific relationship,
t = (F / S) ｛2 (D / R)-(D / R)²｝^1/2
Therefore, the tool feed speed F may be determined from this.
[0035]
FIG. 6A is a perspective view showing a groove 17 formed by this step. By performing the above steps a plurality of times while feeding the diamond cutting tool (spindle device) in the Y direction at a pitch P (= L + M), a plurality of grooves 17 can be formed as shown in FIG. , Can be formed between the grooves 17.
[0036]
Next, the table 15 is rotated by 90 degrees, and the same cutting process as that shown in FIGS. 6A and 6B is performed, so that only the intersection of the triangular ridge is formed as shown in FIG. And the array 1 of the emitter shape 2 in the shape of a quadrangular pyramid is cut out over the entire surface of the substrate 14.
[0037]
In this state, burrs may be formed on the ridge line of the emitter shape 2 due to the flow of the workpiece, but when it is necessary to remove the burrs, FIGS. Burr can be removed by repeating the operation of the same locus again (zero cut). If burrs cannot be completely removed by the zero cut, they can be removed by a cleaning process such as ultrasonic cleaning with acetone.
[0038]
According to such a configuration, since the emitter shape 2 is formed by cutting without using the semiconductor fine processing technology, the following effects can be obtained.
[0039]
First, since the substrate 14 is not limited to a semiconductor wafer, the emitter array 1 can be formed at a time in an area corresponding to all pixels of a large FED.
[0040]
Second, since a semiconductor manufacturing process such as exposure or etching is not used for forming the emitter shape 2, the sharpening of the emitter shape is not restricted by the exposure resolution or the isotropy of the removing action, and the uniform emitter shape is not affected. Shape can be obtained. Further, as will be shown in a later embodiment, it is possible to obtain an emitter shape with a very sharp edge having a radius of curvature of 30 nm or less at the tip.
[0041]
Third, since the cutting process is performed using the rotating tool (diamond cutting tool 9), the amount of one cut can be extremely reduced, and chipping or the like can be prevented, and extremely high sharpness can be obtained. An emitter shape can be formed.
[0042]
In addition, as described above, the method of the present invention is not limited to the case where an emitter shape is formed on a master for obtaining a mold for forming an emitter electrode by a transfer molding method, and the method of directly applying an emitter electrode of a field emission element. It can be applied to the case of forming.
[0043]
Further, the emitter shape 2 is not limited to a quadrangular pyramid, but may be a triangular pyramid as shown in FIG. In this case, the substrate may be rotated by 60 degrees, and the same cutting may be performed in each of the directions A to C.
[0044]
In the case of a quadrangular pyramid, there is a possibility that the part that should be the vertex may remain as a truncated shape due to the setting error of the feed amount and the positioning error of the processing device, but in the case of a triangular pyramid, the vertex is always It has the advantage of being formed.
[0045]
FIG. 8 shows an example in which the distribution of the emitter-shaped array 1 is unevenly distributed. According to the above-mentioned cutting, even such an arrangement can be obtained by unequally changing the feed pitches P1 and P2 in the Y direction.
[0046]
Further, the processing apparatus is not limited to the one shown in FIG. 2, and may be, for example, an apparatus as shown in FIG.
[0047]
The apparatus shown in FIG. 2 rotates the diamond cutting tool 9 about a horizontal axis, but this processing apparatus is an example in which the processing tool is rotated about a vertical axis. Even with such an apparatus, processing similar to that of the above-described apparatus can be performed.
[0048]
At this time, since the cutting chips generated from the substrate 14 fall in the moving direction, the cutting chips tend to adhere below the workpiece. If chips adhere to the surface to be processed before the grooves are formed, the chips are likely to be caught between the diamond cutting tool 9 and the surface to be processed during cutting, so that it is difficult to perform highly accurate groove processing. Therefore, the diamond tool 9 during the groove processing is moved in a direction orthogonal to the direction of gravity. It is preferable to form grooves sequentially by repeating such groove processing from below to above the workpiece. It is preferable to remove the mist-like kerosene by spraying the mist-like kerosene onto the processing point so as to follow from behind the diamond cutting tool 9 which is fed in a direction substantially perpendicular to the direction of gravity. This is effective from the viewpoint of eliminating cutting chips from between the workpiece and the tool and from the viewpoint of lubricating the diamond cutting tool 9 and the workpiece. Cutting chips remaining on the surface of the workpiece after processing can be removed by washing.
[0049]
(Example of the first embodiment)
As an example of the first embodiment, an emitter-shaped array 1 having a side length L = 10 μm, a vertex angle θ = 70 °, a height H = 7 μm, and a pitch P = 20 μm was formed. The product obtained by the processing is used as a master 14 ″ for forming an emitter array for forming an FED device having a screen size of 40 inches on a mold used for transfer molding. However, the substrate 14 obtained by cutting in this manner may be used as it is as an emitter array for forming a field emission device.
[0050]
10 to 11 show schematic diagrams thereof. FIG. 10 is a schematic diagram showing an emitter shape cut out by a cutting process, and FIG. 11 is a schematic diagram showing an emitter shape after zero cutting.
[0051]
The processing accuracy and processing conditions of the processing apparatus when forming this emitter-shaped array will be described below.
[0052]
(1) Processing accuracy of processing equipment
{Circle around (1)} Air spindle of main spindle device: Radial runout of 0.05 μm or less, axial runout of 0.05 μm or less.
[0053]
(2) Gate type head:
Z axis: stroke 100 mm or more, straightness 0.1 μm or less, squareness 0.1 μm or less, positioning accuracy 10 nm or less,
Y axis: stroke 800 mm or more, straightness 0.8 μm or less, squareness 0.8 μm or less, positioning accuracy 10 nm or less,
X-axis: stroke 800 mm or more, straightness 0.8 μm or less, squareness 0.8 μm or less, positioning accuracy 10 nm or less.
[0054]
▲ 3 ▼ Diamond bite:
Shank: length 8mm, width 8mm, length 60mm,
Diamond tip: 70 ° tip angle, 10 μm front cutting edge length, 2 mm cutting edge height, 3 ° front cutting edge relief angle, 3 ° lateral cutting edge relief angle, 60 mm height from the center of the spindle to the top of the diamond tip.
[0055]
(2) Processing conditions
Spindle speed: S = 2000min^-1
X-axis feed rate: F = 100 mm / min
Cutting depth: D = 0.01mm
Cutting amount: t ≦ 1 μm
Y direction feed pitch: P = 20 μm.
[0056]
The included angle of the diamond tip can be arbitrarily changed. The range is generally in the range of 30 ° to 120 °. Therefore, the apex angle of the emitter shape can be set arbitrarily, and the aspect ratio of the emitter shape can also be set arbitrarily, thereby making it possible to form an emitter that easily emits electrons. Become. In the method of processing Si by anisotropic etching, processing can be performed substantially only at an angle of about 70 °.
[0057]
(Second embodiment)
FIG. 12 is a view illustrating a method of manufacturing the field emission device according to the second embodiment of the present invention. In the method of manufacturing the field emission device, the emitter electrode of the field emission device is manufactured using the master disk 14 'manufactured in the first embodiment.
[0058]
First, according to the method of the first embodiment, a size corresponding to a display area required by a display provided with about 38 Hv of oxygen-free copper, about 17 Hv of aluminum (1060-O), and an electroless Ni plating layer. The substrate 14 is cut to form a master 14 'having the emitter array 1 (S1). In addition, other than the above-mentioned metals, other metals which are easy to be mirror-finished with Ra = about 0.01 μm and which are rich in malleability and ductility may be used.
[0059]
Next, the surface of the master 14 'is degreased, and the surface is activated with a fluoride such as ammonium fluoride. Then, the primary surface is placed on the master 14' by electroless Ni plating or electrolytic Ni plating. A Ni electroformed layer 20 made of, for example, 500 Hv electrolytic Ni is transferred (S2). The thickness of the Ni electroformed layer 20 is, for example, about 50 μm. Thereafter, the Ni electroformed layer 20 is peeled from the master 14 '. Thus, the Ni electroforming mold 21 is obtained (S3). Next, the surface of the Ni electroforming mold 21 is subjected to degreasing or anodic oxidation, etc., so that the attached matter is easily peeled off. Thereafter, a Ni electroformed layer 22 of 550 Hv electroless Ni for secondary transfer is formed on the Ni electroformed mold 21 (S4). When the thickness of the Ni electroformed layer 22 is small and it is difficult to obtain mechanical strength, a backing such as a glass substrate may be provided. Thereafter, the Ni electroformed layer 22 is separated from the Ni electroformed mold 21 to obtain a Ni electroformed tool 23 (S5). Since this Ni electroforming tool 23 has an array 24 having a surface area and an emitter shape corresponding to all the pixels of the FED device, it can be used as it is for the field emission device. Since a plurality of Ni electroformed substrates 23 can be obtained from the master 14 ', the processing time can be greatly reduced.
[0060]
By using the thus obtained Ni electroformed substrate 23 as a tool, it is possible to further form a female mold.
[0061]
After the step (S5), the Ni electroforming tool 23 is pressed against a substrate 25 having a surface area corresponding to all pixels of the FED, so that a mold 26 for forming a transfer mold can be obtained by pressing once. Yes (S6).
[0062]
FIG. 14A shows a pressing device for performing this pressing. The pressing device includes a base 28 and a Z-axis table provided on the base 28, which can hold the surface of the substrate 25 to be processed in a state perpendicular to the Z-axis and can position the substrate 25 in the Z-axis direction. 29, and an XY drive head 30 that holds the Ni electroformed tool 23 facing the surface of the substrate 25 and positions and drives the Ni electroformed tool 23 in the XY directions.
[0063]
According to such an apparatus, the Ni electroforming tool 23 is positioned to face the surface of the substrate 25 by the XY drive head 30, and the substrate 25 is driven in the Z-axis direction. Can be pressed.
[0064]
This pressing is performed by pressing the emitter shape 24 of the Ni electroforming tool 23 to a predetermined depth of the substrate 25, maintaining the state for a time required for plastic deformation (for example, 10 seconds), and then pulling apart.
[0065]
In such a pressing process, it is conceivable that bulges 31 (see FIG. 12) occur on the surface of the substrate 25 due to factors such as the material and the like, and the flatness of the surface is lost. In order to cope with this, for example, the machining tool shown in FIG. 14A holds the diamond cutting tool 32 for flat machining near the Ni electroforming tool 23, while attaching the substrate 25 to the Z-axis table 29. Then, the bulge 31 on the surface of the substrate 25 is removed by plane cutting using the diamond cutting tool 32 so as to finish to a predetermined flatness.
[0066]
According to such a configuration, there is an effect that a mold having a size corresponding to the entire area of the FED device can be obtained by a single pressing process.
[0067]
In this embodiment, by using a Ni electroforming tool 23 having a size corresponding to the entire surface of the FED and pressing the Ni electroforming tool 23 against the substrate 25, a mold 26 for transfer molding can be obtained by a single pressing process. However, the present invention is not limited to this. A relatively small electroformed tool may be used and pressed multiple times to obtain a mold having a size corresponding to the entire surface of the FED.
[0068]
For this purpose, as shown in FIGS. 14A to 14F, the pressing of the Ni electroformed tool 23 'is repeated a plurality of times while shifting the pressing position, so that the metal having a size corresponding to the entire surface of the FED is obtained. The mold 26 may be processed. In addition, as shown in FIG. 15F, cutting is performed as shown by a two-dot chain line Q in order to finally obtain flatness. For example, when the pressing operation is repeatedly performed by using the Ni electroforming tool 23 'having the 1000 * 1000 emitter array 24', the number of arrays of the entire FED is 15000 * 8000, so that the time required for one pressing operation is reduced. As about 60 seconds,
Since (15000/1000) × (8000/1000) × 60 sec = 2 hours, it is possible to produce a mold in a very short time of about 2 hours.
[0069]
In this case as well, the swelling 31 may be formed on the surface of the substrate, but it may be removed by plane cutting after the pressing process is completed as described above.
[0070]
The Ni electroformed tool 23 'may be formed by exposing and anisotropically etching a silicon substrate.
[0071]
Further, the processing device for performing the pressing process is not limited to the one shown in FIG. 13A, but may be one as shown in FIG. 13B. This apparatus has a portal head 35, which holds the Ni electroformed tool 23 so as to be positionably driven in the XYZ directions. In addition, the portal head 35 holds a flat processing head 36. The plane processing head 36 has a main shaft (not shown) rotatable about the Z axis, and the diamond cutting tool 27 is attached to the main shaft. Such a device can also perform the same processing as the device shown in FIG.
[0072]
(A) to (c) of FIG. 15 are photomicrographs showing an experimental example in which the concave mold of the emitter was pressed and subjected to plastic working. An electrolytic Ni-plated convex master to which a Si concave mold was transferred was used as a tool, and oxygen-free copper (C1020BD) subjected to an annealing treatment (200 ° C. × 4 h) was used as a workpiece. Processing area is 4mm x 4mm, pushing pressure is 200 ~ 600N / mm²The pressing speed was 0.2 mm / min, and the load holding time was 30 sec. 15 (a) shows the tool before use, FIG. 15 (b) shows the tool after machining, and FIG. 15 (c) shows the workpiece surface after machining at a magnification of 10,000. The shape of the tool tip is transferred to the workpiece. The tip of the tool was rounded and dulled by the processing, and the radius of the tip became 50 to 100 nm. Therefore, it is estimated that the radius of the tip of the emitter shape of the workpiece is also about 50 to 100 nm.
[0073]
From this experimental example, an oxygen-free copper concave mold of an emitter was manufactured using a diamond indenter as a tool and oxygen-free copper as a workpiece, and a larger area oxygen-free copper concave mold was manufactured using an electrolytic Ni-plated convex master to which this was transferred as a tool. It is thought possible. As the tool, an electrolytic Ni-plated convex master to which a Si concave mold is transferred can be used as in the experiment. The hardness of the electrolytic Ni plating is Hv150 to 250 in a Watt bath and Hv400 to 500 in a gloss bath, whereas the hardness of the electroless Ni plating is Hv550 without heat treatment and Hv1100 after heat treatment. The hardness of heat-treated oxygen-free copper (C1020BD) is about Hv38, while the hardness of heat-treated aluminum (1060-O) is about Hv17. Therefore, it is considered that the dullness (roundness) of the tool tip can be reduced by using electroless Ni plating for the tool material and aluminum for the workpiece. It is desirable to select materials as needed.
[0074]
16 and 17 are views showing a method for manufacturing an emitter electrode according to the third embodiment of the present invention. In the first and second embodiments described above, the emitter shape is cut on the surface of the substrate. However, the workpiece is not limited to the substrate, but may be a cylindrical body 40 as shown in FIG. May be.
[0075]
First, as shown in FIG. 16A, the cylindrical body 40 is rotated around its central axis, and the rotating diamond tool 9 is brought into contact with the cylindrical body 40 to form a groove 17 'along the circumference. Then, as shown in FIG. 16 (b), the cylindrical body 40 is rotated by 90 degrees, and the cylindrical body 40 and the diamond cutting tool 9 are moved in the rotational direction at a predetermined pitch in the axial direction of the cylindrical body 40. 6A, the groove 17 ″ orthogonal to the groove 17 ′ can be formed. As a result, the same processing as that shown in FIGS. 6A to 6C can be performed. Then, an emitter shape can be formed over the entire surface of the cylindrical body 40.
[0076]
According to such a processing method, the tool 23 "having the above shape can be formed, and as shown in FIG. 17, the tool 23" is pressed while rotating about an axis parallel to the substrate, and relatively displaced in parallel. Thus, the transfer of the emitter shape to the substrate 25 serving as a mold can be continuously performed. In FIG. 17, reference numeral 41 denotes a roller for pressing the substrate 25 together with the tool 23 ".
[0077]
FIG. 18 is a diagram showing a main part of a flat display device according to a fourth embodiment of the present invention. The flat display device is obtained by using the field emission device formed by using the emitter shape manufacturing method shown in the first to third embodiments.
[0078]
FIG. 18 is an exploded view showing only the configuration of a portion corresponding to one pixel from the FED.
[0079]
This FED is roughly divided into a cathode device 42 arranged on the back side of the display device and an anode device 44 arranged on the display surface side.
[0080]
The cathode device 42 includes a substrate 46 on which the emitter electrode 45 is formed by the above-described method, and an opening that is stacked on the substrate via an insulating layer (not shown) and surrounds the sharpened tip of the emitter electrode 45. And the gate electrode 47. Between the gate electrode 47 and the substrate 46, a silicon oxide film or a silicon nitride film is formed as an insulating layer by using any method such as a CVD method, a sputtering method, an electron beam evaporation method, and a printing method. . The gate electrode 47 is provided on the insulating layer, and is made of a material such as Ni, Cr, W, or an alloy thereof, such as electroless plating, electroplating, printing, sputtering, or vapor deposition. Is formed by applying a removal processing method such as CMP, CDE, RIE, or wet etching to the layer formed by the above process to form an opening surrounding the tip of the emitter electrode 45.
[0081]
Then, by applying a predetermined voltage between the gate electrode 47 and the emitter electrode 45 under a reduced pressure environment, electrons can be emitted from the tip of the emitter electrode 45. That is, the gate electrode 47 and the emitter electrode 45 are connected to a driving circuit (not shown), and electrons can be emitted from an arbitrary emitter electrode 45 by matrix control.
[0082]
On the other hand, the anode device 44 includes a light-transmitting substrate 48 such as glass, an anode electrode 49 such as an ITO film formed on a surface of the light-transmitting substrate 48 facing the cathode device 42, and a surface of the anode electrode 49. , R, G, and B fluorescent films 50a, 50b, and 50c. The anode electrode 49 is connected to a drive circuit (not shown). When a predetermined voltage is applied between the anode electrode 49 and the emitter electrode 45, the electrons emitted from the emitter electrode 45 can be controlled.
[0083]
As a result, electrons can collide with an arbitrary fluorescent film, whereby a desired image can be displayed through the translucent substrate 48.
[0084]
According to such an FED, a high-luminance display can be performed, and a backlight is not required unlike a conventional liquid crystal display. Further, since it can be configured to be very thin, it can be used as a wall-mounted television.
[0085]
It should be noted that the present invention is not limited to the one applied to such an FED, and it goes without saying that various modifications can be made without changing the gist of the invention.
[0086]
As described above, according to the present invention, it is possible to obtain a fine, high-density and highly sharp emitter shape.
[0087]
Now, the above-mentioned emitter has a simple pyramid shape, but various ridge lines can be formed by changing the cutting edge shape of the cutting tool. Changes in the cutting edge shape include a method using a plurality of tools having different cutting edge shapes and a method of adjusting the shape of the cutting edge of a single cutting tool to a desired ridgeline shape. From a viewpoint, the latter is more practical.
[0088]
The angle at which the cutting blades on both sides are arranged when viewed from the direction in which the cutting edge is cut is defined as the cutting edge angle. Figure19As shown in (a), a diamond tip 101 having a cutting edge angle θ1, a diamond tip 102 having a cutting edge angle θ2, and a workpiece 103 from which an emitter shape is cut are prepared. At this time, it is assumed that θ1> θ2. Figure19First, as shown in FIG. 2B, a groove is formed on the workpiece 103 by the diamond tip 101. The diamond chip 102 is cut into the groove formed by an amount smaller than the depth of the groove and cut along the groove. At this time, the width of the cutting edge of the diamond tip 102 is set to be larger than the width of the cutting edge of the diamond tip 101 so that both sides of the groove are cut. This process allows you to19As shown in (c), a truncated pyramid-shaped base portion 104a having a large apex angle and a pyramid-shaped tip portion 104b having a small apex angle existing on the base portion 104a are formed on the workpiece 103. A stepped emitter shape is formed. The diamond chips 101 and 102 may be machined using a plurality of tools each fixed to a different shank.19(D), it is possible to perform processing using one tool in which both diamond chips are fixed to one shank 105. At this time, by setting the distance between the diamond chips to be equal to the width of the groove to be processed, a step-like emitter shape can be obtained by one processing.
[0089]
As described above, according to the present invention, an emitter-like shape having a non-linear ridge can be easily formed.
[0090]
Since the height from the tip of the emitter to the bottom of the emitter is required to be more than a certain level, the minimum possible apex angle has been limited due to the problem of mechanical strength. In the shape of the emitter, the mechanical strength can be compensated by the base, so that the apex angle of the tip can be made smaller. Since the sharpness is enhanced and electrons are easily emitted by the small apex angle, the field emission device having such an emitter can easily provide an image with low power consumption.
[0091]
In addition to the above, various shapes as shown in FIGS. 21A to 21C can be realized. In FIG. 21A, an interruption portion 104c is provided between a base portion 104a and a tip portion 104b. The middle portion 104c can also be easily obtained by appropriately setting the edge angle and the edge width of the tool. z FIG. 21 (b) shows an emitter shape having a wedge-shaped tip portion 105b and a base portion 105a supporting the tip portion 105b. By being formed on the wedge, the amount of emission current increases, which can contribute to improvement in luminance. In addition, even if a defect such as chipping occurs at a part of the wedge tip, electrons are emitted from the other part, which has an advantage of excellent durability.
[0092]
By setting the cutting edge in an arc shape, the emitter shape 106b having an arc ridgeline as shown in FIG. 21C can be formed. Because of the arc shape, the mechanical strength is improved, and the sharpness is easily increased.
[0093]
It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.
[0094]
【The invention's effect】
According to the present invention, it is possible to obtain a fine, high-density and highly sharp emitter shape.
[Brief description of the drawings]
FIG. 1 is an enlarged perspective view showing a row of emitter shapes cut out based on a first embodiment of the present invention.
FIG. 2 is a perspective view showing a cutting device.
FIG. 3 is a view showing a diamond cutting tool.
FIG. 4 is a three side view showing a diamond chip.
FIG. 5 is a schematic view showing a locus of a diamond chip.
FIG. 6 is a process chart for explaining a process of shaving an emitter shape.
FIG. 7 is a plan view showing an emitter shape row of a triangular pyramid.
FIG. 8 is a plan view showing an example in which emitter shape rows are unevenly distributed.
FIG. 9 is a perspective view showing an example of another cutting device.
FIG. 10 is an enlarged photograph of a microscope before performing zero cut.
FIG. 11 is an enlarged photograph of a microscope after performing zero cut.
FIG. 12 is a process chart showing a process of forming a mold used in a transfer mold forming method based on a second embodiment of the present invention.
FIG. 13 is a perspective view showing a pressing apparatus for pressing an electroformed tool against a substrate serving as a mold.
FIG. 14 is a process chart showing an example of another mold forming process.
FIG. 15 (a) is a micrograph of the tool before processing by pressing the concave mold of the emitter before plastic working, (b) is a micrograph of the tool after processing by pressing the concave mold of the emitter and plastic working, and (c) is the micrograph of the tool before processing. Fig. 5 is a micrograph of a processed product after processing by pressing a concave mold and performing plastic working.
FIG. 16 is a view showing the third embodiment of the present invention, and is a view for explaining an example of processing a cylindrical body as a workpiece.
FIG. 17 is a diagram showing a state in which pressing is performed using a cylindrical mold.
FIG. 18 is an exploded perspective view showing the FED.
FIG. 19 is a schematic view showing a case where a groove is formed using a plurality of diamond chips.
FIG. 20 is a perspective view showing one form of a stepped emitter shape.
[Explanation of symbols]
1 ... Emitter array
2 ... Emitter shape
9 ... diamond bite
14, 46 ... substrate
14 '... master
17, 17 ', 17 "... groove
18. Triangle tomb
20 ... Ni electroformed layer
21 ... Ni electroforming mold
22 ... Ni electroformed layer
23,23 '... Ni electroformed tool
23 "… Tool
24 ... array
25 ... substrate
26 ... Mold
40 ... cylindrical body
42 ... Cathode device
44… Anode device
45 ... Emitter electrode
48 ... Transparent substrate
50a to 50c: fluorescent film
103 ... Workpiece

Claims (6)

Method of manufacturing a field emission element characterized by comprising the step of cut out the emitter electrode by cutting a substrate made of a metal. 2. The step of cutting out the emitter electrode according to claim 1, wherein a first cutting step of forming a plurality of grooves in the surface of the substrate that gradually becomes narrower as the depth increases.
A second cutting step of forming a plurality of grooves in parallel on the surface of the substrate in different groove directions and gradually narrowing as the depth increases. . 2. The method according to claim 1, wherein the cutting is performed using a plurality of cutting tools having different cutting angles. 2. A field emission device according to claim 1, further comprising: an emitter electrode having an apex angle of not less than 30 ° and not more than 70 °. 5. The field emission device according to claim 4, wherein the emitter electrode has a shape in which a plurality of line segments or arcs are combined. At least, by the method described in claim 1, it has a plurality of line segments or arcs are combined ridgeline, field emission device and the apex angle is provided is an emitter electrode formed on the 70 ° or less 30 ° or more A cathode device having a gate electrode for emitting electrons from the emitter electrode,
At least an anode device having a light-transmitting substrate provided with a positive electrode for attracting electrons emitted from the cathode device and a luminous body film that emits light when the electrons collide with each other. Flat display device.

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