KR101357940B1 - A multi-particle beam column having an electrode layer including an eccentric aperture - Google Patents

Abstract

The present invention relates to a method for controlling a particle beam in a particle beam column, and more particularly, to provide an electrode layer having an eccentric aperture in the particle beam column to easily control the particle beam column.

Description

A multi-particle beam column having an electrode layer including an eccentric aperture}

The present invention relates to a method for controlling a particle beam in a particle beam column, and more particularly, to provide an electrode layer having an eccentric aperture in the particle beam column to easily control the particle beam column.

The particle beam column is composed of a particle source (emission source) and an electron lens operated by an electrostatic or magnetic field to generate and focus and scan a particle beam such as an electron beam or an ion beam. Ion beam columns using electron columns or ion beams. Such particle beam columns are particularly useful for electron microscopes, semiconductor lithography, or various inspection devices such as via holes / contact holes in semiconductor devices, inspection of specimen surfaces, and the like. It is used for analysis, mask inspection, and inspection of abnormality of TFT (Thin Film Transistor) wiring in display elements such as TFT-LCD and OLED.

The electron beam column is a representative example of the particle beam column. As an example of an electron column that generates, focuses, and scans an electron beam, a micro-column has a diameter of an electron emission source emitting electrons and an aperture through which an electron passes, sub-500 micrometers or less. It was first introduced in the 1980s as manufactured on the basis of a microstructured electro-optic component. The microelectronic column is finely assembled with fine components to minimize the optical aberration to form an improved electronic column, and the small structure can be arranged in a multi-type electronic column structure of parallel or series structure. For this purpose, the aperture of the lens is made into a membrane by a microelectronic mechanical system (MEMS) process to make a lens from a silicon wafer using a semiconductor process. Also used.

1 is a diagram showing the structure of an ultra-small electron column, in which an electron emission source, a source lens, a deflector, and an Einzel lens are aligned to scan an electron beam.

A microcolumn, typically an ultra-small electron column, consists of an electron emitter 110 emitting electrons indicated by an arrow, three electrode layers to emit, accelerate, and control electrons and forming the emitted electrons into an effective electron beam. A source lens 120, a deflector 150 for deflecting the electron beam, and a focus lens (Einzel lens 140) for focusing the electron beam on a sample s. Generally, the deflector is located between the source lens and the Einzel lens. For normal operation of the microcolumn, a negative voltage (about -100 V--2 kV) is applied to the electron emission source, and the electrode layers of the source lens are generally grounded. As an example of a focusing lens, an Einzel lens focuses an electron beam by grounding both external electrode layers and applying a negative voltage (deceleration mode) or a positive voltage (acceleration mode) to the center electrode layer. (Used to focus). At the same operating distance, the magnitude of the focusing voltage in the deceleration mode is smaller than in the acceleration mode. A synchronized deflecting voltage is applied to the deflector to regulate the path of the electron beam to scan the electron beam at regular intervals on the specimen surface. The electron lens, such as the source lens or the focusing lens, includes two or more electrode layers having apertures or apertures having a predetermined shape so as to allow the electron beam to pass through the center, .

As described above, the types of micro electron columns described in the representative electron beam column include a single micro electron column composed of one particle beam emitter and electron lenses for controlling the particle beam generated from the particle beam emitter and a plurality of electron beams. It is divided into a multi-type micro electron column composed of electron lenses for controlling a plurality of particle beams emitted from an electron emission source. A multi-type microelectron column is a wafer including a particle beam emitter having a plurality of particle beam emitter tips in one electrode layer, such as a semiconductor wafer, and an electron lens in which a lens layer having a plurality of apertures is formed in one electrode layer is stacked. A single compact electron column, a combined compact electron column and a single tiny electron column that control the particle beam beam emitted from individual particle beam emitters such as a single electron column with a single lens layer with multiple apertures It can be divided into an array (array) method used in mounting. In the case of the combination type, the particle beam emission sources are separately divided, and the lenses can be used in the same manner as the wafer type.

In the particle beam column as described above, a particle beam is generated and focused from a particle source source to scan a sample. In some cases, the particle beam column may be used by detecting ions or electrons in a sample current manner. This sample current method, in which the conductor portion is connected to the outside of the sample, and ions or electrons injected directly into the sample are directly detected, can be directly detected from the outside, is used for detecting whether or not a via hole / contact hole of a semiconductor device is abnormal Inspection, surface inspection and analysis of samples, and inspection of TFT (Thin Film Transistor) abnormality in TFT-LCD devices. However, when used as a multi-beam beam column for throughput problems such as processing speed in the case of inspection or a microscope as described above, there is a problem that control of the multi-beam column is not easy.

In order to solve the above problems, an object of the present invention is to make it easy to control the scanning by utilizing the electrode layer eccentric in the aperture of the conventional multi-particle beam column.

The present invention relates to a multi-particle beam column in which two or more particle beam columns including a particle beam emitter, a deflector, and an electron lens having two or more electrode layers are combined, wherein the multi-particle beam column is a particle beam of an individual column. And at least one electrode layer (hereinafter referred to as an eccentric electrode layer) whose aperture is eccentric from the optical axis.

In another aspect of the present invention, in the multi-particle beam column, the apertures of the eccentric electrode layer are arranged so that they do not overlap at different positions on the individual beam optical axes, and the scanning of the particle beam is controlled in the same column in each column, so that the multi-particle beam It is characterized in that the particle beams scanned in the individual columns of the column are not simultaneously scanned into the sample.

In addition, the present invention is characterized in that in the multi-particle beam column, the eccentric electrode layer is disposed below the deflector.

In addition, the present invention is characterized in that in the multi-particle beam column, the eccentric electrode layer is not included in the focus electrode and is disposed below the focus lens as a separate layer, or two or more of the eccentric electrode layers are collected to form an electron lens.

By using the particle beam multi-column having the eccentric electrode layer according to the present invention, the deflector can be easily controlled through one controller in the same way as the multi-multiplied columns such as the multi-micro electron column.

In addition, scanning the multi-particle beam by moving the sample through the stage can magnify the sample as if it were a microscope, or improve throughput during inspection.

1 is a diagram showing the structure of a microelectronic column.
2 is a cross-sectional view showing an example of the use of the eccentric electrode layer of the present invention.
3 is a plan view of an example of an eccentric electrode layer of the present invention.
4 is a plan view of another example of the eccentric electrode layer of the present invention.
5 is a plan view of another example of an eccentric electrode layer of the present invention.

In the present invention, by introducing an eccentric electrode layer in two or more multi-particle beam columns and scanning the same type of deflector in the same direction with the same voltage in the same direction, a plurality of multi-columns in a large area sample in a detection method such as a sample current method. It is to be used. In particular, in this case, the advantage of using a stage to move the multi-column and / or the sample can be further increased by further increasing the processing speed. For example, a four-pole deflector in the form of + is arranged in four electrodes in each single column with the same orientation, and the same voltage is applied to each of the deflector electrodes in the same orientation, and the particle beam is scanned, as described below. The beams scanned in the column are alternately scanned in the sample instead of being simultaneously scanned in the sample, so that beam detection can be easily performed in a sample current manner.

Hereinafter, the principle of the present invention will be described in more detail with reference to the accompanying drawings.

As shown in Fig. 2, electrons from the electron emission source 10 that emits an electron beam, which is a representative example of a particle beam, are indicated by arrows. The electrons are scanned at the deflector 50 across the electron lens 20 represented as one large quadrangular box, and the entire beam is not normally scanned into the sample by the eccentric electrode layer 130 eccentric to the beam optical axis below. Only a portion of the sample (s) will be scanned. The left and right two electron columns scan the electron beam on the same sample, but different eccentric electrode layers 130 are used so as not to overlap each other on the optical axis. As shown, the apertures of the eccentric electrode layers 130 on the normal optical axis are eccentric with each other in an outward direction.

Therefore, if the electron beam is deflected while being synchronized with the same detector structure in the same direction, only the deflected portion of the existing whole scan area is scanned into the sample, and the area actually scanned is reduced, but the electron beam scanned from two columns at the same time is simultaneously applied to the sample. It will not be injected. That is, in Fig. 2, the left column is scanned normally on the basis of the electron optical axis, but the right part is not scanned, and the right column is scanned normally on the right, but the left part is not scanned. Is not injected into the same sample.

3 to 5 illustrate examples of the eccentric electrode layer 130 described with reference to FIG. 2 in more detail.

3 and 4 are examples of an eccentric electrode layer 130 that can be used for two columns.

FIG. 3 is made in a circle away from the optical axis X in a direction away from each other as shown in FIG. 4 shows two apertures 132 made in a semicircle away from the optical axis in a direction away from each other as in FIG. 2, which is reduced in half so as not to be scanned simultaneously with each other in the original size. As shown in FIG. 4, if the size of the aperture 131 of the eccentric electrode layer 130 is the same as that of the original lens, all of the actual aperture sizes may not be used for scanning. In other words, as shown in FIG. 2, the entirety may not be used. That is, the size can be determined by considering the actual scan size.

FIG. 5 is arranged with respect to the optical axes X and Y so that four circles of 1/4 size each do not overlap with the eccentric electrode layer 130 usable for four columns. When four columns are used, the aperture 133 is preferably not smaller than the size of the original aperture so that the actual aperture size does not overlap. This does not mean the size of the actual circle, as described in the example of Figure 3, but rather the sum of the areas where the actual beam is scanned.

If eight columns are used, each aperture will again be smaller. As such, in the case of a multicolumn of n × m arrays, the individual apertures will be smaller.

Although each aperture is described above as a circle, various apertures such as the shape of an actual polygon may be used. In this case, as described above, the aperture may be determined based on the optical axis so that it is eccentric and does not overlap. In addition, the eccentric direction can also be determined so as not to overlap.

In addition, the above-described eccentric electrode layer 130 has been described as a single layer having a plurality of apertures. However, when a plurality of single columns are separately arranged, individual electrode layers may be individually placed in the original eccentric position in a single column. You can arrange them so that they are arranged. That is, the eccentric electrode layer 130 shown in FIGS. 3 to 5 may be divided and used for each single column. However, in the case of using individual single columns, it is difficult to mount a part of each column in a single column to fit its position rather than the eccentric electrode layer 130 which is one layer. Therefore, in order to prevent the beams scanned on the sample from overlapping, it is preferable that the effective aperture size of the entire single column is smaller than the existing aperture size.

130: eccentric electrode layer
10: electron emission source
20: electronic lens
50: deflector

Claims (5)

A multi-particle beam column comprising two or more particle beam columns coupled to a particle beam emitter, a deflector, and an electron lens having two or more electrode layers,
The multi-column has at least one electrode layer (hereinafter referred to as an eccentric electrode layer) with apertures eccentric from the beam optical axis of the individual columns,
The apertures of the eccentric electrode layers are arranged so that they do not overlap at all different positions on the optical axis of the individual beams and the scan of the beams is controlled equally in the individual columns, so that each scanned in the individual columns of the multi-electron column To prevent the particle beam from being scanned simultaneously into the sample, and
The eccentric electrode layer being disposed below the deflector,
Multi-particle beam column characterized in that. delete delete The multi-particle beam column according to claim 1, wherein two or more eccentric electrode layers gather to form an electron lens. 5. The multi-particle beam column of claim 1 or 4, wherein the eccentric electrode layer is disposed as the last electrode layer in the path of travel of the beam.

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