JP2007328038A - Dimension calibration sample for microscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dimension calibration sample for a microscope which can be used in common to microscopes to mainly perform measurement of several μm to hundreds μm. <P>SOLUTION: The dimension calibration sample for the microscope is equipped with: a transparent substrate; a transparent or translucent first conductive film formed on the transparent substrate; and an opaque or translucent second conductive film formed on the first conductive film. A dimension calibration pattern is formed of the second conductive film, and the first conductive film is exposed at a part where the dimension calibration pattern does not exist. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a dimensional calibration sample for a microscope. The present invention particularly relates to a dimensional calibration sample for a microscope that can be shared by different types of microscopes such as a scanning electron microscope and an optical microscope.

  In the measurement area of the extremely small dimension area (1 μm or less) that is measured by the scanning electron microscope, the standard microscale (lattice pattern pitch 240 nm ± 1 nm, but the inclusion coefficient K = 2) is used as a standard sample traceable to the national standard. It is used.

  In Patent Document 1, a rectangular pattern is formed using a lithography technique, and an arbitrary plurality of pattern pitches are measured with a scanning electron microscope exclusively for length measurement calibrated using a standard microscale, and the average value is standardized. A method of creating a traceable standard sample for dimensional calibration for a measurement region of several μm to several hundred μm by providing as a value is disclosed.

JP 2003-179321 A

  The electron microscope forms an image by generating secondary electrons. A portion where an inclination or an edge is formed with respect to the flat portion of the sample appears bright due to generation of more secondary electrons. For this reason, the dimensional calibration sample of the electron microscope has a mechanism that allows measurement by recognizing the pitch of the uneven pattern formed on the single substrate of the semiconductor material.

  On the other hand, the laser microscope forms an image by the difference in the reflectance of the substrate. Therefore, it is desirable that the pattern to be a dimension calibration sample is made of materials having different reflectivities, and the concave portion is transparent.

  In addition, a transparent substrate is required for a transmission optical microscope that emits light from the lower surface.

  An existing dimensional calibration sample in a minute dimension region (several μm to several hundred μm) is based on observation with an electron microscope and is formed of a single semiconductor material. Therefore, it could not be used with a laser microscope or a transmission optical microscope.

  In laser microscopes and transmission optical microscopes, there are no existing calibrated specimens that are traceable to national standards and SI unit systems, and there is a problem that the dimensions measured with laser microscopes and transmission optical microscopes are not reliable. . Further, there is a problem that a dimensional error occurs when the same sample is measured with a plurality of different types of microscopes and consistency cannot be obtained.

  In addition, recent lasers and optical microscopes have an increasing resolution of several μm or less, which is close to that of electron microscopes. By calibrating dimensions using the same sample, It is desired to unify micro dimension measurement management in many fields.

  In view of the above, an object of the present invention is to provide a microscope dimensional calibration sample that can be shared by main microscopes that measure several μm to several 100 μm.

  A dimensional calibration sample for a microscope according to the present invention includes a transparent substrate, a transparent or translucent first conductive film formed on the transparent substrate, and an opaque or translucent film formed on the first conductive film. And a second conductive film, wherein a dimension calibration pattern is formed by the second conductive film, and the first conductive film is exposed at a portion where the dimension calibration pattern is not present.

Preferably, the light reflectance of the first conductive film is different from that of the second conductive film.
Preferably, the material of the transparent substrate is quartz, glass, or plastic, the material of the first conductive film is indium tin oxide, and the material of the second conductive film is silicon, tantalum, or titanium.

  Preferably, a code or number pattern for identifying the dimension calibration pattern is formed on the same surface on which the dimension calibration pattern is formed.

Preferably, the dimension calibration pattern is formed in two directions orthogonal to each other.
Preferably, a search guide pattern indicating the position of the dimension calibration pattern is formed on the same surface on which the dimension calibration pattern is formed.
Preferably, a plurality of the dimension calibration patterns having different dimensions are formed.

  ADVANTAGE OF THE INVENTION According to this invention, the dimension calibration sample for microscopes which can be shared by the main microscope which measures several micrometer-several hundred micrometer can be provided.

  FIG. 1 is a top view and a cross-sectional view showing an example of a dimensional calibration sample for a microscope according to the present invention. Three dimensional calibration patterns 2 having different sizes are formed on the substrate 1. These dimension calibration patterns are rectangular patterns, and are generally used as microscope dimension calibration patterns. Taking the upper right dimension calibration pattern as an example, a calibration mark pattern 3 and a pitch name pattern 4 are formed in the vicinity thereof. The calibration part mark pattern 3 is used for easily recognizing a calibration location in the dimension calibration pattern during dimension calibration. As a result, dimension calibration can always be performed at the same location in the dimension calibration pattern. The pitch name pattern 4 is for identifying the pitch dimension of the rectangular pattern that is a dimension calibration pattern. When the pattern pitch dimension is described in a certificate issued by the organization that calibrated the pattern pitch, the pitch name pattern 4 is used. Same name as. On the substrate 1, a sample No. for identifying the microscope dimensional calibration sample is shown. A pattern 6 is also formed. The upper left dimension calibration pattern is formed in two directions orthogonal to each other. In this way, calibration in both the vertical and horizontal directions can be performed without moving the microscope calibrating sample.

  As shown in FIG. 2, an arrow-shaped search guide pattern from multiple directions toward the dimension calibration pattern may be formed so that the dimension calibration pattern can be easily searched.

  The transparent substrate 1 has a smooth surface and transmits light, and the material is preferably, for example, quartz, glass, or plastic. A transparent or translucent first conductive film 5 is formed on the transparent substrate 1. The first conductive film 5 is formed by depositing a transparent conductive film such as ITO or by depositing an ultra-thin metal that can minimize the reflectance. On the first conductive film 5, the second conductive film 2, which is an opaque or translucent conductive metal film having a lower transmissivity and a higher reflectance than the first conductive film 5, is formed. The material of the second conductive film 2 is preferably, for example, silicon, tantalum or chromium. Thereafter, a dimensional calibration pattern 2 that is a rectangular pattern is formed using a lithography technique such as reduced projection exposure or chemical etching. The first conductive film 5 is exposed at portions other than the dimension calibration pattern 2. The calibration part mark pattern 3, the size name pattern 4 and the sample number 6 are formed by means such as lithography or laser beam processing.

  The dimensional calibration sample for a microscope manufactured in this way can be used for an electron microscope because conductivity is ensured throughout by the first conductive film and the second conductive film. When used in an electron microscope, the dimensional calibration pattern 2 is formed by the second conductive film existing as a convex portion on the first conductive film, so that more secondary electrons are formed in the portion forming the edge. It looks bright when it occurs. Therefore, the pitch of the pattern can be recognized and measurement is possible.

  When used in an optical microscope, when light is irradiated from below, a portion without the dimension calibration pattern 2 is formed of the transparent substrate 1 and the transparent or translucent first conductive film 5 and thus appears bright. Appears dark due to the presence of an opaque or translucent second conductive film. Therefore, the pitch of the pattern can be recognized and measurement can be performed.

  When used in a laser microscope, the light reflectance of the second conductive film in the portion of the dimension calibration pattern 2 is different from that of the first conductive film in the portion without the dimension calibration pattern 2. Therefore, the pitch of the pattern can be recognized and measurement can be performed.

  The pattern pitches at a plurality of arbitrary positions of the dimension calibration pattern are measured with a length-measuring scanning electron microscope calibrated using a standard microscale, and the average value is given as a standard value. In this way, traceability to national standards can be ensured.

  FIG. 3 is a flowchart for explaining the traceability system of the dimensional calibration sample for a microscope according to the present invention. The National Institute of Advanced Industrial Science and Technology has an absolute measurement device that is a national standard. The Japan Quality Assurance Organization (JQA) is an organization that performs verification / calibration of measuring instruments. JQA has an optical pitch measuring device calibrated by a minute dimension absolute measuring device. The pattern for dimensional calibration of the dimensional calibration sample for microscope according to the present invention is calibrated by using this optical pitch measuring apparatus. A calibration certificate as shown in FIG. 6 is issued to the microscope calibrated sample thus calibrated. In this way, traceability to national standards is established.

  FIG. 4 is a flowchart showing a method of calibrating a microscope using the microscope dimensional calibration sample of the present invention. An optical microscope and an electron microscope will be described as examples. The dimensional calibration pattern (fine pattern, ultrafine pattern) of the dimensional calibration sample to be used is calibrated by the same organization using the same apparatus (in the above example, the JQA optical pitch measuring device) by the same method. Shall.

  When calibrating an optical microscope, for example, a fine pattern with a pitch of several hundreds of μm is used. FIG. 5 a is a diagram for explaining the principle of calibration of an optical microscope. The light emitted from the light source 7 is converted into parallel light by the condenser lens 8 and passes through the dimension calibration pattern of the microscope dimension calibration sample 9. The light that has passed through the dimensional calibration pattern is focused by the objective lens 10 and the projection lens 11 and forms an image on the screen 12. Since the part other than the dimension calibration pattern of the dimension configuration sample 9 for the microscope is made of the transparent or semi-transparent first conductive film, a lot of light is transmitted, and the part of the dimension calibration pattern is the opaque or semi-transparent second conductive film. Therefore, it does not transmit much light. Accordingly, the image 13 of the dimension calibration pattern is formed on the screen 12. The dimension calibration pattern image 13 is measured by an automatic calibration application of an optical microscope. The configuration value of the dimensional calibration sample for the microscope is input to the specified location, and the calibration of the optical microscope is completed.

  When configuring an electron microscope, for example, a very fine pattern with a pitch of several μm is used. FIG. 5b is a diagram for explaining the principle of the configuration of the electron microscope. The electron beam emitted from the electron source 14 is focused by the electron lens 15 and scanned on the dimension calibration pattern of the microscope dimension calibration sample 9 by the polarizing coil 16. Secondary electrons generated from the dimension calibration pattern of the microscope dimension calibration sample 9 are detected by the secondary electron detector 18, converted into an electrical signal, and displayed on the CRT screen 19 as an image of the dimension calibration pattern. . Since the dimensional calibration pattern portion is constituted by the convex portion, the portion forming the edge looks bright due to generation of more secondary electrons. The image of the pattern for dimensional calibration is repeatedly measured, and the average value is input to the calibration application prescribed part of the electron microscope. The configuration value of the dimensional calibration sample for the microscope is input to the specified location, and the calibration of the electron microscope is completed.

  The present invention can be used for a dimensional calibration sample for a microscope.

It is the top view and sectional drawing which show an example of the dimension calibration sample for microscopes by this invention. It is a top view which shows the guide pattern for search. It is a flowchart explaining the traceability system of the dimension calibration sample for microscopes. It is a flowchart which shows the method of calibrating an apparatus using the dimension calibration sample for microscopes. It is a figure explaining the principle of the apparatus which uses the dimension calibration sample for microscopes. It is a figure which shows an example of the calibration certificate of the dimension calibration sample for microscopes.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Size calibration pattern 3 Calibration part mark pattern 4 Size name pattern 5 Transparent conductive film 6 Sample number 7 Lamp (light source)
8 Condenser lens 9 Sample 10 Objective lens 11 Projection lens 12 Screen 13 Calibration pattern 14 Electron source 15 Electron lens (condenser)
16 Polarizing coil 17 Sample 18 Secondary electron detector 19 CRT screen 20 CRT

Claims (9)

A transparent substrate;
A transparent or translucent first conductive film formed on the transparent substrate;
An opaque or translucent second conductive film formed on the first conductive film,
A dimension calibration sample for a microscope, wherein a dimension calibration pattern is formed by the second conductor film, and the first conductive film is exposed in a portion where the dimension calibration pattern is not present.   The dimensional calibration sample for a microscope according to claim 1, wherein the light reflectance of the first conductive film is different from that of the second conductive film.   2. The dimensional calibration sample for a microscope according to claim 1, wherein the material of the transparent substrate is quartz, glass or plastic.   The dimensional calibration sample for a microscope according to claim 1, wherein the material of the first conductive film is indium tin oxide.   The dimensional calibration sample for a microscope according to claim 1, wherein the material of the second conductive film is silicon, tantalum or titanium.   2. The dimensional calibration sample for a microscope according to claim 1, wherein a code or number pattern for identifying the dimensional calibration pattern is formed on the same surface on which the dimensional calibration pattern is formed.   The dimensional calibration sample for a microscope according to claim 1, wherein the dimensional calibration pattern is formed in two directions orthogonal to each other.   2. The microscope dimension calibration sample according to claim 1, wherein a search guide pattern indicating a position of the dimension calibration pattern is formed on the same surface on which the dimension calibration pattern is formed.   2. The dimension calibration sample for a microscope according to claim 1, wherein a plurality of the dimension calibration patterns having different dimensions are formed.

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