X-ray inspecting device, X-ray thin film inspecting method, and method for measuring rocking curve

Patent metadata

Field	Value
Publication number	US-10876978-B2
Application number	US-201716205801-A
Country	US
Kind code	B2
Filing date	Jul 12, 2017
Priority date	Jul 15, 2016
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

In an X-ray inspection device according to the present invention, an X-ray irradiation unit 40 includes a first X-ray optical element 42 for focusing characteristic X-rays in a vertical direction, and a second X-ray optical element 43 for focusing the characteristic X-rays in a horizontal direction. The first X-ray optical element 42 is constituted by a crystal material having high crystallinity. The second X-ray optical element includes a multilayer mirror.

First claim

The invention claimed is:

1. An X-ray inspecting device comprising:
a sample stage on which an inspection target sample is placed;
image observing means for observing an image of the sample placed on the sample stage;
a positioning mechanism that is controlled based on an image observation result of the sample by the image observing means to move the sample stage in two orthogonal directions on a horizontal plane, a height direction, and an in-plane rotation direction;
a goniometer including first and second rotation members that rotate independently of each other along a virtual plane perpendicular to a surface of the sample around a rotational axis contained in the same plane as the surface of the sample placed on the sample stage;
an X-ray irradiation unit that is installed in the first rotation member and focuses and irradiates characteristic X-rays to an inspection position set in the same plane as the surface of the sample placed on the sample stage;
an X-ray detector installed in the second rotation member, wherein the X-ray irradiation unit includes an X-ray tube for generating X-rays, and an X-ray optical element for receiving X-rays irradiated from the X-ray tube, extracting only characteristic X-rays of a specific wavelength and focusing the extracted characteristic X-rays on the inspection position, and the X-ray optical element includes a first X-ray optical element for focusing the characteristic X-rays so that a height of the characteristic X-rays decreases within a virtual vertical plane orthogonal to the surface of the sample and containing an optical axis, and a second X-ray optical element for focusing the characteristic X-rays so that a width of the characteristic X-rays decreases within a virtual plane orthogonal to the virtual vertical plane and containing the optical axis, and wherein the first X-ray optical element is constituted by a crystal material having high crystallinity, and the second X-ray optical element comprises a multilayer mirror; and
rocking curve measuring means for executing a method for measuring rocking curve on a sample in which a thin film crystal is epitaxially grown on a substrate crystal, wherein the rocking curve measuring means has a function of executing the following operations (I) to (VI):
(I) selecting two equivalent asymmetrical reflection crystal lattice planes for the sample;
(II) arranging the X-ray irradiation unit and the X-ray detector at angular positions for the sample surface determined based on a Bragg angle of the substrate crystal in the sample for one of the selected crystal lattice planes;
(III) irradiating the sample surface with X-rays from the X-ray irradiation unit, and detecting a reflection angle and intensity of diffracted X-rays reflected from the sample by the X-ray detector;
(V) arranging the X-ray irradiation unit and the X-ray detector at angular positions for the sample surface determined based on a Bragg angle of the substrate crystal in the sample for the other selected crystal lattice plane;
(V) irradiating the sample surface with X-rays from the X-ray irradiation unit, and detecting a reflection angle and intensity of diffracted X-rays reflected from the sample by the X-ray detector; and
(VI) obtaining a rocking curve based on the reflection angle and intensity of the diffracted X-rays detected by the X-ray detector, and analyzing data on the rocking curve,
wherein the rocking curve measuring means further has a function of executing the following operations (VI-I) to (VI-IV) in the operation (VI):
(VI-I) determining an angular difference between a diffraction peak in the substrate crystal of the sample and diffraction peaks of two equivalent asymmetric reflections in the thin film crystal of the sample;
(VI-II) calculating a lattice constant of the thin film crystal of the sample from the angular difference of the diffraction peaks determined by the operation (VI-I);
(VI-III) calculating, from a known elastic constant of the thin film crystal of the sample and the calculated lattice constant, at least one of a strain of the thin film crystal, a lattice constant under a state where a stress of the thin film crystal is released, a composition of the thin film crystal and the stress of the thin film crystal; and
(VI-IV) outputting a calculation result obtained by the operation (VI-III).

2. The X-ray inspecting device according to claim 1 , wherein the first X-ray optical element uses a crystal material and is configured to reflect X-rays by lattice planes having an inherent rocking curve width of 0.06° or less in the crystal material.

3. The X-ray inspecting device according to claim 1 , wherein the X-ray irradiation unit includes a focusing angle control member for controlling a focusing angle of the characteristic X-rays in the virtual vertical plane orthogonal to the surface of the sample and containing the optical axis.

4. The X-ray inspecting device according to claim 3 , wherein the focusing angle control member comprises a slit member having a slit for transmitting only a part having any width of the characteristic X-rays focused by the first X-ray optical element.

5. The X-ray inspecting device according to claim 4 , wherein the X-ray irradiation unit is configured so that respective components of the X-ray tube, the X-ray optical element, and the slit member are incorporated in an unit main body that is rotatably installed in the first rotation member.

6. The X-ray inspecting device according to claim 1 , wherein the X-ray detector comprises a one-dimensional X-ray detector or a two-dimensional X-ray detector.

7. A method for measuring rocking curve that uses the X-ray inspecting device according to claim 1 to perform a rocking curve measurement on a sample in which a thin film crystal is epitaxially grown on a substrate crystal and includes the following steps A to D:
step A of selecting two equivalent asymmetric reflection crystal lattice planes for the sample;
step B of arranging the X-ray irradiation unit and the X-ray detector at angular positions for the sample surface determined based on a Bragg angle of the substrate crystal in the sample for one of the selected crystal lattice planes;
step C of irradiating the sample surface with X-rays from the X-ray irradiation unit, and detecting a reflection angle and intensity of diffracted X-rays reflected from the sample by the X-ray detector;
step D of arranging the X-ray irradiation unit and the X-ray detector at angular positions for the sample surface determined based on a Bragg angle of the substrate crystal in the sample for the other selected crystal lattice plane;
step E of irradiating the sample surface with X-rays from the X-ray irradiation unit, and detecting a reflection angle and intensity of diffracted X-rays reflected from the sample by the X-ray detector; and
step F of obtaining a rocking curve based on the reflection angle and intensity of the diffracted X-rays detected by the X-ray detector, and analyzing data on the rocking curve,
wherein the step F further includes the following steps F-1 to F-4:
step F-1 of determining an angular difference between a diffraction peak in the substrate crystal of the sample and diffraction peaks of two equivalent asymmetric reflections in the thin film crystal of the sample;
step F-2 of calculating a lattice constant of the thin film crystal of the sample from the angular difference of the diffraction peaks determined by the operation of the step F-1;
step F-3 of calculating, from a known elastic constant of the thin film crystal of the sample and the calculated lattice constant, at least one of a strain of the thin film crystal, a lattice constant under a state where a stress of the thin film crystal is released, a composition of the thin film crystal and the st

Assignees

• Rigaku Denki Co Ltd

Inventors

• Ogata Kiyoshi
• Omote Kazuhiko
• YOSHIHARA Sei
• Ito Yoshiyasu
• Motono Hiroshi
• Takahashi Hideaki
• Kinefuchi Takao
• HIGUCHI Akifusa
• Umegaki Shiro
• Asano Shigematsu
• YAMAGUCHI Ryotaro
• HORADA Katsutaka
• Kambe Makoto
• Jiang Licai
• Verman Boris

Classifications

• G21K5/02

  having no beam-forming means · CPC title

• G21K1/06

  using diffraction, refraction or reflection, e.g. monochromators (G21K1/10, G21K7/00 take precedence) · CPC title

• G01N2223/1016

  X-ray · CPC title

• G01N23/20025

  Sample holders or supports therefor · CPC title

• G01N23/207 Primary

  Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions · CPC title