JPS6313234A - Measurement device for electron gun - Google Patents

Abstract

PURPOSE:To measure an off-centering and a bending amount between the electrodes of an electron gun with high precision, by reading the directional positions of X and Y when screen images of two electrodes passing through the electron beam through-apertures coincide with original point of X and Y lines, and obtaining a difference in the readings. CONSTITUTION:An electron gun 4 is vertically inserted in a socket 9 on tables 5 and 6 in X and Y directions respectively, light from a light source 2 is radiated on the electron gun through an object lens 3, and a magnified image of it is projected on a screen 1. In this case, firstly, focussing of the image is applied on an electron beam through-aperture of the first grid of the electron gun 4, and the positions of the tables 5 and 6 in the X and Y directions are read when the center of the magnified image coincides with the original point of the X and Y lines. Secondly, the focussing is applied to the electron through- aperture of a shield cup, and the same procedure as the above is carried out. Thus, an off-centering and a bending amount between the first grid and the shield cup are obtained from difference in the above two readings. Therefore, the measurement can be performed in directly and quantitatively with high precision.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is capable of measuring the eccentricity and bending amount between each electrode of an electron gun with an accuracy of 0.01 m+a without tiring the eyes of the operator. This invention relates to an electron gun measurement device.

[Conventional technology]

In order to emit a well-focused narrow electron beam from the electron gun, the centers of the electron beam passage holes of each electrode (so-called grids, shield cups, etc.) of the electron gun must all be aligned in a straight line (
It is desirable that it be located on the electron gun axis).

Conventionally, in order to measure the eccentricity and bending of each electrode that makes up the electron gun, measurements were taken using a projection microscope with the outside of the electron gun as a reference. The dimensional accuracy of the parts existing between the center and the outside of the electrode, which has traditionally been the standard, is not necessarily good, and as a result, the eccentricity of the center of the electron beam passage hole of each electrode of the electron gun,
It was not possible to measure bending with high precision.

Conventionally, alignment of electron beam passing holes of electrodes constituting an electron gun is disclosed in, for example, Japanese Patent Laid-Open No. 100331/1983.

[Problem that the invention seeks to solve]

The present invention solves the above-mentioned problems of the conventional technology and provides an apparatus that can directly measure eccentricity and bending between the centers of electron beam passing holes of each electrode constituting an electron gun with high precision. purpose.

[Means for solving problems]

In order to solve the above problems, in the present invention, the electron gun to be measured is stood upright on the X and Y table of the projection microscope, which has a scale up to 0.01 nm and can be moved minutely, and the electron gun to be measured is magnified. The image is projected onto the screen surface, and first, focus on a certain electrode, and align the center of the enlarged image of the electron beam passage hole of this electrode on the screen with the origin of the X and Y lines on the screen surface. Read the position of the table when matched, then focus on another electrode,
Read the position of the table when the center of the enlarged image of the hole of the electrode on the screen coincides with the origin of the X and Y lines on the screen surface, and determine the position of the table in the x and y directions when the two electrodes are in focus. The eccentricity and amount of bending between these two electrodes were determined from the difference in the reading values.

[Effect]

Generally, the depth of focus of a microscope is shallow, so an electrode (or shield cup) is used to measure the center of the electron beam passage hole.
At 0 magnification, it is necessary to focus separately and read the position of the table in the X and Y directions each time. Since there is no microscope, it is not possible to capture each electrode within the depth of focus at the same time, and there is no way to focus separately.In addition, the individual techniques required to fully automate this device are Although there are currently some technologies that control each operation sequentially and comprehensively, it is possible to create a device that can be mass-produced.

Between the center of the electron beam passage hole of each electrode of the electron gun and the outside of the electrode, the outer wall of the electrode is inserted and supported by an electrode support rod (made of so-called multiform glass with high insulation properties). Although care is taken to firmly support the electrode support, it is usually necessary to rely on an electron gun assembly jig to align the centers. Therefore, the tolerance of the distance between the center of the electron beam passage hole and the outside of the electrode is not very strict. In this regard, conventionally, it was inappropriate to take the outside of each electrode that constitutes the electron gun as the reference plane, and the correct approach is to use the center of the electron beam passage hole of each electrode as the measurement reference, as in the present invention. I can say it.

〔Example〕

FIG. 1 shows an embodiment of the present invention, where 1 is a screen, 2 is a screen, and 2 is a screen.
is an illumination source, 3 is an objective lens, 4 is an electron gun, 5 is an X-direction table, 6 is a Y-direction table, 7 is a shield cup, 8
is the first grid, and 9 is the socket. FIG. 2 is a schematic cross-sectional view of an example of an electron gun to be measured, and shows the polarization of the first grid 8 closest to the cathode (not shown) and the shield cup closest to the phosphor surface (not shown). Measure the core and bend.

Determine the socket position alignment in advance using a mask gauge. Insert the stem outer bin of the electron gun into the socket that serves as a reference when standing the electron gun upright on the microscope table, set the electron gun at the measurement position, and focus on the electron beam passage hole of the first grid 8. At the same time, place the hole at the 0th order to project the enlarged image on the screen.
X so that it matches the Y cursor line (if it matches both cursor lines, it will be on the intersection of the X and Y lines).

Drive the Y table. Read the drive amounts XA and YA.Furthermore, move the vertical slide drive unit to focus on the electron beam passage hole of the shield cup, and project the enlarged image on the screen, as in the case of the first grid. Then, drive the X, Y table so that the hole matches the cursor line, and read the amount of drive XB, y. The difference in image motion amount, ie, XA-XB and YA-YB, is due to the eccentricity of the electron beam passing hole in the first grid and the electron beam passing hole in the shield cup, or the bending of the electron gun axis.

〔Effect of the invention〕

As explained above, according to the present invention, the true eccentricity and bending of the electron gun itself, which actually affect the formation and focusing of the electron beam, can be quantitatively measured, and the accuracy control of the electron gun can be improved.
Useful for mass production inspection, failure analysis, etc.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of an example of an electron gun to be measured. 1-Screen, 2-Illumination source, 3-Objective lens, 4-electron gun, 5--X direction table, 6-
・Y-direction table, 7--shield cup, 8--
1st grid, 9-socket. Agent: Patent attorney Katsuma Ogawa (Figure 2, Figure 1, Figure 2)

Claims (1)

[Claims] 1. Place the electron gun to be measured upright on the X and Y tables of the projection microscope so that its magnified image is projected onto the screen. First, focus on a certain electrode, and When the center of the magnified image on the screen of the electron beam passage hole coincides with the origin of the X and Y lines on the screen surface, read the position of the table in the X and Y directions, then focus on another electrode and Read the position of the table in the X and Y directions when the center of the enlarged image of the electrode hole on the screen coincides with the origin of the X and Y lines on the screen surface, and read the table position when the two electrodes are in focus. An electron gun measuring device characterized in that the eccentricity and bending amount between these two electrodes are determined from the difference in values.