JPS636717A - Electron-emitting device - Google Patents

Abstract

PURPOSE:To obtain an exact positional relation to a material to be processed, by using a transparent insulating substrate divided into two regions and mounting electron-emitting elements in a region and alignment marks in the other region in an electron emitting device where electron emission is induced by application of a voltage. CONSTITUTION:A surface of a transparent insulating substrate 2 made of a material such as glass is divided into two regions, and one region is used as a region 2a for electron-emittingelement formation and the other region is used as a region 2b for alignment-mark formation. The first metallic layer 4 made of the plural number Al stripes or the like arranged at regular intervals is mounted in the region 2a, and the whole surface containing them is covered with an insulating layer 6 made of SiO2 or the like, and then the end part of the layer 4 is equipped with terminals 10 for application of the driving voltage. The second metallic layer 8 consisting of the plural number of stipes made of the same material is then formed perpendicularly to the layers 4 on the layer 6, and it is also connected with terminals 12. A plurality of alignment marks 14 are disposed directly on the substrate 2 in the region 2b. Hence, high- precision electron irradiation can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electron-emitting device, and particularly to an electron-emitting device having an electron-emitting element whose electron emission is induced by application of a voltage. Such an electron emitting device is suitably used as an electron generation source in various electron beam application devices such as electron beam exposure devices.

[Prior Art] Thermionic emission from a hot cathode has conventionally been used as an electron generation source. Electron emission using such a hot cathode has the disadvantages that there is a large energy loss due to heating, that it is necessary to form a heating means, that it takes a considerable amount of time for preheating, and that the system is easily destabilized by heat. There was a problem with that.

Therefore, research into electron-emitting devices that do not rely on heating is progressing, and several types of devices have been proposed.

For example, there are types that apply a reverse bias voltage to the PN junction to cause an electron avalanche breakdown phenomenon and emit electrons to the outside of the element, and those that have a metal-insulator layer-metal layer structure and are connected between the two metals. There are types (MIM type) in which electrons that have passed through the insulator layer are emitted from the metal layer to the outside of the element due to the tunnel effect by applying a voltage to the metal layer. A surface conduction type in which a voltage is applied to emit electrons from the surface of the thin film to the outside of the element, or a metal in which a voltage is applied to a metal whose shape is likely to cause electric field concentration to generate a locally high density electric field. A field-effect CFE type (field-effect CFE type) in which electrons are emitted from the element to the outside of the element, and other types have been proposed.

As an application example of these electron-emitting devices, a plurality of these devices are arranged two-dimensionally, and electron emission from each of these devices is controlled to 0N at appropriate times.
- By controlling OFF, electrons are emitted in a desired pattern, and the emitted electrons are allowed to collide with the surface of the workpiece as is or after being accelerated and deflected by appropriate means, and surface processing or surface modification is performed by electron beam exposure. It is possible to do this.

[Problems to be Solved by the Invention] Among the electron-emitting devices as described above, the MIM-type electron-emitting device has the advantage that an applied voltage can be relatively low and that it does not require a very high degree of vacuum.

When constructing the electron beam exposure apparatus using MIM type electron-emitting devices, it is difficult to achieve sufficient alignment with the workpiece by simply arranging only the devices. In the case of electron beam exposure, especially high-definition pattern exposure is required, so 7-line is an extremely important working condition.

[Means for Solving the Problems] According to the present invention, in order to solve the problems of the prior art as described above, the first
at least one electron-emitting device is disposed, the electron-emitting device having at least one metal layer, an insulator layer, a second metal layer, and means for applying a voltage between the first and second metal layers; Further, there is provided an electron-emitting device, characterized in that the substrate has a region where the electron-emitting device is not arranged and a mark for 7 alignments is attached.

[Example] Hereinafter, specific examples of the present invention will be described with reference to the drawings.

FIG. 1(&) is a partial plan view showing an embodiment of an electron emitting device according to the present invention, and FIG. 1(b) and FIG. 1(C)
are a BB sectional view and a CC sectional view, respectively.

In these figures, reference numeral 2 denotes a substrate, which is a parallel plane plate that is substantially transparent and electrically insulating. The substrate is made of glass, ceramics, crystal, etc., for example. The substrate 2 is an electron-emitting device.

It has a region 2a for forming seven alignment marks and a region 2b for forming seven alignment marks.

In the element formation region 2a, a plurality of first metal layers 4 having a predetermined width and extending in the CC direction are arranged in parallel at regular intervals on the substrate z. and.

An insulator layer 6 is formed so as to cover the substrate 2 and the first metal M4 thereon over the entire area of the element formation region 2a. Further, on the insulating layer, a plurality of second gold N layers 8 having a predetermined width and extending in the B-B direction are arranged in parallel at regular intervals. A terminal IO for applying a driving voltage is connected to each of the first metal layers 4, and a terminal 12 for applying a driving voltage is connected to each of the second metal layers 8. Thus, an MIM structure (ie, an electron-emitting device) is formed at the position where the first metal layer 4 and the second metal layer 8 overlap.

The first metal layer 4 is made of, for example, AI, Be, or Mo.

Pt, Ta, Au, Pd, Ag, W, Cr, Mg.

Made of nichrome etc. The metal layer 4 may be a layer made of an alloy containing some of these metals or a layer made of silicide of these metals. The thickness of the metal layer 4 is not particularly limited, but is, for example, 0.001 to 1. It is about 1.0 m.

The insulator layer 6 is made of, for example, 5i02 or Ta205.

A l 203 , Be O, S t C, S z O
xNyHz.

SiN x Hy phosphorus silicate glass (PSG
).

Consists of AIN, BN, etc. The thickness of the insulator M6 is preferably as thin as possible to prevent dielectric breakdown.

This thickness is preferably set as appropriate to obtain desired electron emission characteristics depending on the type of insulator used for the layer 6, the type of metal used for the second metal layer 8, etc. Approximately 10 to 2,000 people.

Further, the second metal layer 8 is made of the same material as the first metal layer 4 described above. The thickness of the metal layer is preferably as thin as possible from the viewpoint of electron emission efficiency, for example, Zoo~3000
It is about the size of a person.

The alignment mark forming region 2b is located at the end of the substrate 2, and the alignment mark 14 is formed here. The mark can be formed by printing, mask vapor deposition, photolithography, etc., and is made of a fully curved material, an organic material, or the like. The alignment mark 14 may be embedded in the substrate 2, and has light absorption or light scattering properties.

The device of this embodiment can be used in an electron beam exposure device. FIG. 2 is a partial sectional view showing the state of use in such a usage form.

In FIG. 2, numeral 20 is a wafer holder, and this holder holds a workpiece such as silicon urchin/\22.The apparatus 24 of this embodiment is arranged so that the substrate 2 is parallel to the surface of the wafer 22. Placed. A mark for alignment (not shown in FIG. 2) is formed on the wafer 22, and the mark has a shape related to the alignment mark 14 of the apparatus of this embodiment. The apparatus 24 of this embodiment is arranged so that the alignment mark 14 of the mark forming region 2b faces the alignment mark of the wafer 22.

In FIG. 2, reference numeral 26 denotes an objective lens of an optical alignment machine, which is arranged so that its optical axis is perpendicular to the substrate 2 at a position corresponding to the mark forming area 2b of the apparatus 24 of this embodiment. In the above alignment machine, objective lens 2
An observation optical system (not shown) is provided below 6.

FIG. 3 is a diagram showing an alignment observation state in the observation optical system of the alignment machine.

In FIG. 3, 30 is an image of the alignment mark formed on the wafer 22, and 32 is an image of the 7 alignment mark 14 on the substrate 2. As shown in the figure, the mark image 30 and the mark image 32 are are in proper positional relationships horizontally and vertically, thereby confirming that the apparatus 24 of this embodiment is accurately aligned with the wafer 22'.

In FIG. 2, only one set of the alignment mark attached to the wafer 22 and the alignment mark 14 of the apparatus 24 of this embodiment is shown, but the wafer 22 has two or more similar alignment marks at different positions. A mark is formed, and correspondingly, two or more marks are also formed on the substrate 2 of the device 24 of this embodiment, and alignment is performed with respect to a set of the two or more marks.

In this embodiment, the mark image 30 and the mark image 32 formed on the observation optical system of the alignment machine may be visually observed. The beam is irradiated onto the wafer 22 in the form of a spot and scanned in the direction shown by arrow A in FIG. 3 to measure the intensity change of the reflected light, and the decrease in intensity when the beam spot crosses the mark image 30. It is also possible to automatically detect the relative positional relationship between the two mark images 30 and 32 from the timing.

FIGS. 4(a) and 4(b) are diagrams showing alignment inspection conditions in the observation optical system of the alignment machine, and both of these states are states in which alignment is not performed accurately. In this case, the pattern of changes in reflected light intensity during scanning of the light beam spot is different from that shown in FIG. Achieve an accurate alignment state as shown in .

After achieving an accurate alignment state, each electron-emitting device is activated by applying a voltage such that the terminal 12 side is positive between the appropriate terminal 10 and the appropriate terminal 12 of the device 24 of this embodiment. Matrix driven. As a result, electrons are emitted upward from the second metal layer 8 of the electron-emitting device to which a voltage is applied, and the surface of the wafer 22 is pattern-exposed with the electron beam.

In the above embodiment, an example is shown in which the electron-emitting devices are arranged two-dimensionally, but in the apparatus of the present invention, the electron-emitting devices may be arranged one-dimensionally. In order to expose the surface of an object with a two-dimensional pattern, appropriate elements may be driven at appropriate times while moving the entire apparatus relative to the workpiece in a direction transverse to the direction in which the electron-emitting elements are arranged.

In the above embodiment, the electrons emitted from the electron-emitting device are directly irradiated onto the workpiece, but if necessary, the electrons emitted from the electron-emitting device may be accelerated and/or deflected by appropriate means. Further, the workpiece may be irradiated with the irradiation light, and such acceleration means and/or deflection means may be constructed integrally with the apparatus of the present invention.

[Effects of the Invention] According to the present invention as described above, since the electron-emitting device and the alignment mark are formed on the same substrate,
Alignment with an object to be irradiated with electrons such as a workpiece can be performed extremely accurately, making it possible to irradiate electrons with good accuracy.

[Brief explanation of the drawing]

FIG. 1(a) is a partial construction view of the electron-emitting device, and the first
FIG. 1(b) and FIG. 1(C) are a BB sectional view and a CC sectional view, respectively. FIG. 2 is a partial sectional view showing how the electron beam exposure apparatus is used. FIG. 3 and FIGS. 4(a) and 4(b) are diagrams showing alignment observation states. 22 substrate, 2a: electron-emitting device formation region, 2b core alignment mark formation region, 4.8: metal scrap, 6: insulator layer, 10.12:
Terminal, 14: Alignment mark, 22: Wafer, 3Q,
32: Alignment mark image. Agent Patent Attorney Tane Yamashita Figure 1 (b) Figure 1 (c) Figure 2 Figure 3

Claims (1)

[Claims] (1) A first metal layer, an insulator layer, a second metal layer, and means for applying a voltage between the first and second metal layers on an insulating substrate that is transparent and has good planarity. an electron-emitting device, wherein at least one electron-emitting device is disposed, and the substrate has a region where an alignment mark is attached without disposing the electron-emitting device. .