JP3977312B2 - Manufacturing method of electron source substrate - Google Patents

Description

  An application field of the present invention is an electron emission having a pair of element electrodes and a conductive thin film connecting the element electrodes on an insulating substrate, and an electron emission portion is formed in a part of the conductive thin film The present invention relates to a method of manufacturing an electron source substrate configured by arranging a plurality of elements.

  In recent years, FPDs and PDPs are becoming more and more popular as display elements for large displays such as airport waiting rooms and large TVs and large TVs. An electron source substrate as a kind of display element of FPD does not leak to the example, and it is becoming increasingly necessary to increase the size.

  An electron source substrate is an electron-emitting device having a pair of device electrodes and a conductive thin film connecting the device electrodes on an insulating substrate, and an electron-emitting portion is formed in a part of the conductive thin film Is a display substrate configured by arranging a plurality of electrodes, and particularly, a substrate in which a surface conduction electron-emitting device is formed as an electron source.

  Conventionally, two types of electron-emitting devices using a thermionic electron-emitting device and a cold cathode electron-emitting device are known. Cold cathode electron-emitting devices include field emission type (hereinafter referred to as “FE type”), metal / insulating layer / metal type (hereinafter referred to as “MIM type”), surface conduction type electron emitting device, and the like.

  As an example of the FE type, one disclosed in Non-Patent Document 1 or Non-Patent Document 2 below is known.

  On the other hand, as an example of the MIM type, one disclosed in Non-Patent Document 3 below is known.

Examples of the surface conduction electron-emitting device type include those disclosed in Non-Patent Document 4 below. The surface conduction electron-emitting device utilizes a phenomenon in which electron emission occurs when a current flows through a small-area thin film formed on a substrate in parallel to the film surface. As this surface conduction electron-emitting device, a device using a SnO ₂ thin film by Elinson et al. In Non-Patent Document 4, a device using Au thin film (the following Non-Patent Document 5), a device using In ₂ O ₃ / SnO ₂ thin film (the following) Non-patent document 6), and those using carbon thin films (the following non-patent document 7) have been reported.

  As a typical example of these surface conduction electron-emitting devices, a device configuration by M. Hartwell of Non-Patent Document 6 is schematically shown in FIG. In the figure, 11 is a glass substrate, and 12 and 13 are a pair of element electrodes formed on the glass substrate 11 so as to face each other. 14 is a conductive thin film made of a metal oxide thin film or the like formed by sputtering or the like in an H-shaped pattern, and the electron emission portion 15 is formed by an energization process called energization forming. In the figure, the element electrode interval L is 0.5 to 1 mm, and W is 0. 1 mm is set. Note that the position and shape of the electron emission portion 15 are schematically shown because they are uncertain.

As an inexpensive and simple fabrication method for surface conduction electron-emitting devices,
Applying a liquid containing the material of the conductive thin film between a pair of electrodes in the form of droplets, detecting the application state of the droplets between the electrodes, and based on the information obtained regarding the application state, A method of creating an electron source substrate by applying droplets between the electrodes (Patent Document 1 below),
A method of forming a plurality of conductive films electrically connected to a common wiring, the step of detecting an arrangement state of the common wiring or a member attached to the common wiring, and based on the detected result A step of calculating position information relating to a position to which a plurality of conductive film materials electrically connected to a common wiring are applied; and a material of the conductive film is applied to a plurality of positions based on the position information. A method for forming a conductive film (Patent Document 2 below), which is characterized by having a step.
JP-A-9-69334 (European Patent Application Publication No. 717428A2) JP 2000-251665 A (European Patent Application Publication No. 936652A1) WP Dyke & WW Dolan, "Field emission", Advance in Electron Physics, 8, 89 (1956) CA Spindt, "PHYSICAL Properties of thin-film field emission cathodes with molybdenium cones", J. Appl. Phys., 47, 5248 (1976) CA Mead, "Operation of Tunnel-Emission Devices", J. Appl. Phys., 32, 646 (1961) MI Elinson, Radio Eng. Electron Phys., 10, 1290 (1965) G. Dittmer, "Thin Solid Films", 9, 317 (1972) M. Hartwell and CG Fonstad, "IEEE Trans. ED Conf.", 519 (1975) H. Araki et al., Vacuum, Vol. 26, No. 1, p. 22 (1983)

  However, as the droplet application area increases with the size of the substrate, it is extremely difficult to maintain the total positional accuracy (distortion) of the electrodes (or their substitute parts) on the entire surface of the substrate in the same manner as a small-sized substrate. In addition, the accuracy of variation in substrate thickness tended to deteriorate. Therefore, in order to accurately eject and apply droplets to all element electrode positions on the substrate, it has been necessary to increase the number of measurement points for the element electrode positions.

  The time to measure multiple locations on the device electrode is determined by moving the substrate and positioning the device electrode pattern within the field of view of the measurement optical system, and then controlling the position within the focal range of the optical system. It was necessary to repeat the operation of measuring as many times as the number of measurement points, and time corresponding to the number of measurement points was required.

  The present invention has been made in view of the above circumstances, and a first object thereof is one step in order to discharge a metal-containing solution in a droplet state onto a substrate with high accuracy and at a high speed. The time required for measuring the target position of the substrate is reduced. The second purpose is to eliminate the time difference between the measurement of the target position of the substrate and the time of discharging the droplet, and to eliminate the thermal expansion error due to the change in the temperature of the substrate. The third object is to provide a method of manufacturing an electron source substrate using a high-speed and high-precision droplet application technology that discharges and applies droplets while measuring a target pattern of the substrate.

In order to solve the above-described problems, a method for manufacturing an electron source substrate according to the present invention is a method for manufacturing an electron source substrate,
Scanning a substrate having a plurality of electrode pairs on the surface, X perpendicular to each other of the substrate, Y, relatively unidirectionally at least one of the measuring means for measuring at least a position of the substrate in one direction of the Z-direction And measuring step of measuring the position of a plurality of electrode pairs located on the substrate ,
On the basis of the result of the measuring step, the liquid to a plurality of electrode pairs from the ink jet head while scanning at least one relatively one direction the substrate and the ink jet head for discharging a droplet containing a material of the conductive thin film A discharge step of discharging and applying droplets,
The measuring means and the inkjet head are scanned without changing their relative positions, and the position measurement of the electrode pair different from the electrode pair from which the droplet is discharged is performed during the droplet discharging process to the electrode pair. It is performed.

In particular, it is preferable to repeat the measurement process and the ejection process after the inkjet head and the substrate are moved stepwise in a direction perpendicular to the scanning direction.

  Moreover, it is preferable that the measurement unit and the inkjet head are integrally formed.

  In that case, the measurement means and the inkjet head may be arranged in parallel with respect to the scanning direction in the measurement process or the ejection process.

  Alternatively, the measurement unit and the inkjet head may be arranged orthogonal to the scanning direction in the measurement process or the ejection process.

In the ejection step , the ejection timing of the droplets from the inkjet head may be controlled based on the result of the measurement step. In the ejection step , at least one of the inkjet head and the substrate may be controlled. The scanning direction when scanning in one direction relatively may be controlled .

Also, before the discharging step, and more preferably further comprising a preliminary discharge step of discharging pre-droplets from the ink jet head.

  The electron source may further include a surface conduction electron-emitting device and a forming step of performing energization forming on the conductive thin film formed by the droplets applied by the discharging step.

  According to the present invention, it is possible to reduce the time for measuring the target position of the substrate, which has been one step in order to accurately and rapidly discharge the metal-containing solution onto the substrate in a droplet state. Since the time difference between the measurement of the target position of the substrate and the time of droplet discharge can be eliminated and the thermal expansion error due to changes in the substrate temperature etc. can be eliminated, the droplet discharge / It is possible to provide a method for manufacturing an electron source substrate using a high-speed and high-precision droplet applying technique for applying. Moreover, the electron source substrate manufactured by said method can be provided.

  Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

  3 is a schematic view showing an example of a method for manufacturing an electron-emitting device in the method for manufacturing an electron source substrate of the present invention, and FIG. 4 is a schematic view showing an example of a surface conduction electron-emitting device manufactured by the manufacturing method. It is a figure, (a) is a top view, (b) is sectional drawing.

  3 and 4, 11 is a substrate, 12 and 13 are element electrodes, 14 is a conductive thin film, 15 is an electron emission portion, 31 is a droplet discharge head, and 32 is a droplet.

  The method for manufacturing the electron-emitting device including the pre- and post-processes of the present invention will be described in order.

  First, in the pre-process of the present invention, the device electrodes 12 and 13 are formed on the substrate 11 with a distance L (FIG. 3A). Next, with the apparatus of the present invention, a droplet 32 made of a solution containing a metal element is ejected from the droplet ejection head 31 (FIG. 3B) so that the conductive thin film 14 is in contact with the element electrodes 12 and 13. (FIG. 3C). Next, a crack is formed in the conductive thin film by, for example, forming treatment, and the electron emission portion 15 is formed (FIG. 3D).

  Note that a method for forming an element electrode and a method for forming an electron emission portion by a forming process have been described in the prior art (Patent Document 1, Patent Document 2) and the like, and will not be described.

  As the droplet discharge head, an ink jet type that can be controlled in the range of about 10 ng to several tens of ng and can easily form a minute amount of droplets of about 10 ng to several tens of ng is preferable. As an inkjet head, an inkjet jet head using a piezoelectric element or the like, a system in which bubbles are formed in a liquid by thermal energy, and the liquid is ejected as droplets (hereinafter referred to as a bubble jet (registered trademark) system) Inkjet ejecting head and the like.

  The conductive thin film 14 is particularly preferably a fine particle film composed of fine particles in order to obtain good electron emission characteristics. The film thickness is determined by step coverage to the device electrodes 12 and 13 and the resistance value between the device electrodes 12 to 13. Although it is set as appropriate depending on the energization forming conditions, etc., it is preferably several to several thousand, and particularly preferably 10 to 500.

The most characteristic feature of the electron source substrate manufacturing method of the present invention is that the substrate has a plurality of electrodes on the surface and the position of the substrate in at least one of the X, Y, and Z directions orthogonal to each other. A measuring step for measuring the position of the substrate by scanning at least one of the measuring means for measuring the relative position in one direction, and discharging a droplet containing the material of the conductive thin film based on the result of the measuring step A control step of controlling a discharge position of droplets from the ink jet head (hereinafter also simply referred to as “head”) to the substrate, and at least one of the ink jet head and the substrate is relatively moved based on the control step A discharge step of discharging and applying droplets containing a material of a conductive thin film between the pair of electrodes on the substrate surface from the inkjet head while scanning in one direction,
The scanning direction in the measurement step and the scanning direction in the discharge step are substantially parallel, and the measurement step and the discharge step are performed during one scan.

  The scanning target in the measurement process and the discharge process of the present invention is preferably a substrate. In this case, relative movement of the substrate with respect to the head and the measurement unit can be performed by moving only the substrate while the head and the measurement unit are stationary.

  Various arrangements of measuring instruments for measuring the position of the substrate are conceivable. In any case, a position as close as possible to the head is desirable. For example, as shown in FIG. 6, if the measuring instruments are arranged at two positions in front of and behind the head in parallel with the scanning direction of the substrate, a desired position where a droplet should be discharged in both forward and backward directions is measured. However, it takes extra time to scan the distance between the head and the measuring instrument. In addition, for example, as shown in FIG. 7, it is arranged only in front of the head in parallel with the scanning direction of the substrate, and a desired position where a droplet should be ejected in one direction of advance and retreat is measured and stored. In this case, it can be said that the stored data is used, but an extra time is required for scanning the distance between the head and the measuring instrument.

  As another example of the arrangement, as shown in FIG. 8, there is a case where the head and the measuring means are arranged in a direction perpendicular to the direction of scanning the substrate with respect to the head and the measuring means. In this case, it is necessary to measure and store a desired position on the substrate by performing scanning for the measurement means to measure the line to be ejected first. After that, after the substrate is moved in the direction perpendicular to the scanning direction with respect to the head and the measuring means (this movement is called step movement), the operations of the position control process and the ejection process are performed.

  In any case, after this scanning (for example, the X direction), droplets are ejected and applied onto a substrate within a scanning distance range including directly under the inkjet head, and then a desired direction (Y direction) perpendicular to the scanning direction is obtained. The position control process and the ejection process are repeated again while moving the distance (step movement) and scanning the substrate and the head relatively in the X direction at that position. By repeating this, it is possible to eject and apply droplets at high speed and with high accuracy to a large-area substrate that is longer than the length of the head.

  Next, FIG. 1 is a schematic view of an electron source substrate manufacturing apparatus according to an embodiment of the present invention.

  In FIG. 1, 101 is a main body surface plate for mounting the apparatus, 102 is a vibration isolator for supporting the surface plate 101 and blocking external vibrations, and 103 is a Y stage that is provided on the surface plate and performs a large stroke movement. Guide shaft, 104 Y-stage linear motor, 105 Y-stage Y-stage Y-stage X-axis guide shaft function, 106 X-stage drive linear motor, 107 X-axis function X-stage, 108 Is a plate on which a substrate is mounted, 109 is a head unit composed of an inkjet head, 110 is an XY measurement optical system for measuring the pattern position (XY direction) on the substrate, and 111 is for measuring the position of the substrate in the Z direction. Z measuring optical system, 112 is a Z moving unit for moving the measuring optical system in the Z direction, and 113 is a head unit 109 in the substrate scanning direction (X direction). Head moving unit that moves in a direction perpendicular to the direction (Y, Z direction), 114 is a Z moving unit and a column that supports the head moving unit, 115 is a laser optical system for measuring the stage position, and 116 is a discharge nozzle of an inkjet head. A cleaning unit and a drive system for cleaning a surface and stabilizing a discharge amount and a discharge position.

  FIG. 2 is a flowchart for explaining a method of manufacturing an electron source substrate by the above manufacturing apparatus of the present invention. A description will be given along the process of this figure.

"Process S11"
The substrate that is the source of the electron source substrate is mounted on the plate 108 on the X and Y stages of the manufacturing apparatus and vacuum-adsorbed.

“Process S12”
The position of the upper surface of the substrate is measured by the Z measurement optical system 111, and based on the measurement result, the XY measurement optical system 110 is moved in the Z direction to enter the focal range, and the substrate and head in the X, Y, and θ directions The relative positional relationship between and is measured. As a preferred method, the XY measurement optical system 110 reads an alignment mark provided on the substrate with a sensor such as a CCD, analyzes the image information obtained there, and analyzes the relative information between the substrate and the head. Measure the relative position.

  This measurement may be performed for a plurality of marks using a plurality of measurement optical systems, or may be performed for a plurality of marks by moving the stage using a single measurement optical system. Further, a pattern such as an element electrode may be read instead of the alignment mark.

"Process S13"
Based on the measurement result of the process, the position of the X and Y stages is adjusted to correct the relative position between the substrate and the head on the stage.

"Process S14"
In order to stabilize the discharge position and discharge amount of the ink jet head, preliminary discharge is performed at a place where droplets can be discharged. As a dischargeable place, a preset area on the substrate, a set area outside the substrate on the stage, or a tray that receives liquid droplets to be discharged may be moved directly below the head. It is also an effective method to clean the head ejection surface by observing the surface condition of the head ejection surface, the adhesion of extra droplets, etc., and using the recovery function described later. Note that this step may be omitted if the discharge position and the discharge amount of the inkjet head are stable.

"Process S15"
The substrate is scanned in one direction (for example, the X direction) relative to the Z measurement optical system 111 and the XY measurement optical system 110, and the positions in the X, Y, and Z directions orthogonal to each other on the substrate are measured. . The target of the position to be measured is preferably a pattern of a plurality of locations selected in advance from all the pattern of element electrodes in the area where the droplet is ejected from the head in step S16.

"Process S16"
The substrate is moved relative to the head in a direction (Y direction) perpendicular to the scanning direction in step S15 (step movement).

"Process S17"
Based on the measurement results of the plurality of patterns measured in the step S15 in the X, Y, and Z directions, droplets are ejected onto the substrate while the head and the substrate are scanned in one direction (for example, the X direction) relatively. X, Y, Z directions on the substrate orthogonal to each other in the area where the position is controlled and the droplet is ejected from the head to a desired position on the substrate and the droplet is to be ejected in the next step. Measure the position of.

  Next, as in step S16, the substrate is moved stepwise relative to the head in a direction (Y direction) perpendicular to the scanning direction.

  Next, as in step S17, droplets are ejected while the substrate is scanned in one direction relative to the head, and areas where droplets are to be ejected next are orthogonal to each other on the substrate. The position in the X, Y, Z direction is measured. The discharge position control specifically includes discharge timing, scanning direction correction, stage θ (angle) correction, and the like.

Thereafter, the liquid droplets are accurately discharged and applied to all desired areas on the substrate by repeating the same steps as in steps S16 and S17. The position measurement need not be performed in all three directions of X, Y, and Z. For a substrate with sufficient substrate thickness accuracy, only X and Y (θ as necessary) need be measured. Conversely, when the precision of the arrangement pattern of the device electrodes is sufficient, not good at measuring the Z-direction only. In addition, in the formation of element electrodes, if the displacement of the arrangement pattern of the element electrodes is directional, measurement in any one direction of X and Y (θ as necessary) may be performed in consideration of the directionality. Absent.

  In this example, the substrate position measuring means is provided at the position in the Y direction of the head. However, as described in the section of the embodiment, the substrate position measuring means is set in the X direction ( It is also considered as a variation of the present invention to be provided at a position in the scanning direction), in which case step S15 is considered to be included in S17.

  The conductive film thus formed was subjected to the above-described energization forming to form an electron source substrate having an electron source composed of a surface conduction electron-emitting device.

  As described above, in the above embodiment, the head and the substrate are relatively scanned in one direction (X direction) based on the measurement results in the X, Y, and Z directions of a plurality of patterns on the substrate. X, which controls the discharge position of the liquid droplets on the substrate, discharges the liquid droplets from the head to a desired position on the substrate, and X, Since the means for measuring the positions in the Y and Z directions is provided, it is not necessary to measure in advance the pattern positions of all areas to be ejected on the substrate before ejection, and the measurement time can be drastically reduced.

  In addition, it is preferable to add recovery means for the ink jet head, preliminary auxiliary means, and the like provided as the configuration of the manufacturing apparatus because the effects of the present invention can be further stabilized. Specifically, capping means, cleaning means, pressurizing or suction means for the ink-jet head, preheating means using an electrothermal converter or a heating element different from this, or a combination of these, original ejection It is also effective to perform a preliminary discharge mode different from that in order to perform stable discharge.

It is the schematic of the manufacturing apparatus of the electron source board | substrate which concerns on one Embodiment of this invention. It is a flowchart for demonstrating the manufacturing method of the electron source board | substrate by said manufacturing apparatus of this invention. It is a schematic diagram which shows an example of the manufacturing method of the electron-emitting element in the manufacturing method of the electron source board | substrate of this invention. It is a schematic diagram which shows an example of the surface conduction electron-emitting device manufactured by the manufacturing method of this invention, (a) is a top view, (b) is sectional drawing. It is a schematic diagram of a conventional surface conduction electron-emitting device. FIG. 5 is a plan layout view of an example in which measuring instruments are arranged at two positions in front of and behind the head in parallel with the scanning direction of the substrate. It is a plane layout view of an example in which a measuring instrument is arranged only in front of the head in parallel with the scanning direction of the substrate. It is a plane arrangement view of an example in which measuring instruments are arranged next to the head on a line perpendicular to the scanning direction of the substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Substrate 12,13 Element electrode 14 Conductive thin film 15 Electron emission part 31 Droplet discharge head 32 Droplet 101 Main body surface plate 102 Vibration isolator 103 Y stage guide shaft 104 Linear motor 105 Y stage 106 Linear motor 107 X stage 108 Plate 109 Head unit 110 XY measuring optical system 111 Z measuring optical system 112 Z moving unit 113 Head moving unit 114 Column 115 Laser optical system 116 Cleaning unit and driving system

Claims (10)

A method for manufacturing an electron source substrate, comprising:
Scanning a substrate having a plurality of electrode pairs on the surface, X perpendicular to each other of the substrate, Y, relatively unidirectionally at least one of the measuring means for measuring at least a position of the substrate in one direction of the Z-direction And measuring step of measuring the position of a plurality of electrode pairs located on the substrate ,
On the basis of the result of the measuring step, the liquid to a plurality of electrode pairs from the ink jet head while scanning at least one relatively one direction the substrate and the ink jet head for discharging a droplet containing a material of the conductive thin film A discharge step of discharging and applying droplets,
The measuring means and the inkjet head are scanned without changing their relative positions, and the position measurement of the electrode pair different from the electrode pair from which the droplet is discharged is performed during the droplet discharging process to the electrode pair. A method of manufacturing an electron source substrate, which is performed. 2. The electron source substrate according to claim 1, wherein at least one of the inkjet head and the substrate is relatively moved stepwise in a direction perpendicular to a scanning direction , and then the measurement step and the ejection step are repeated. Production method.   The method of manufacturing an electron source substrate according to claim 1, wherein the measuring unit and the inkjet head are integrally formed.   The method of manufacturing an electron source substrate according to claim 3, wherein the measuring unit and the inkjet head are arranged in parallel to a scanning direction in the measuring step or the discharging step.   4. The method of manufacturing an electron source substrate according to claim 3, wherein the measuring unit and the inkjet head are arranged orthogonal to the scanning direction in the measuring step or the discharging step. 2. The method of manufacturing an electron source substrate according to claim 1, wherein in the discharging step , the discharge timing of the droplets from the inkjet head is controlled based on the result of the measuring step. 2. The scanning direction in which at least one of the inkjet head and the substrate is relatively scanned in one direction is controlled based on a result of the measurement step in the ejection step . Manufacturing method of electron source substrate. The method of manufacturing an electron source substrate according to claim 1, further comprising a preliminary discharge step of preliminary discharging droplets from the inkjet head before the discharge step.   The method of manufacturing an electron source substrate according to claim 1, wherein the electron source includes a surface conduction electron-emitting device.   10. The method of manufacturing an electron source substrate according to claim 9, further comprising a forming step of performing energization forming on the conductive thin film formed by the droplets applied by the discharging step.

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