X-ray surface analysis and measurement apparatus

Patent metadata

Field	Value
Publication number	US-2016178540-A1
Application number	US-201615060477-A
Country	US
Kind code	A1
Filing date	Mar 3, 2016
Priority date	Feb 28, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

This disclosure presents systems for x-ray diffraction/scattering measurements that have x-ray flux and x-ray flux density several orders of magnitude greater than existing x-ray technologies. These may therefore be useful for applications such as structural analysis and crystallography.
The higher brightness is achieved in part by using designs for x-ray targets that comprise a number of microstructures of one or more selected x-ray generating materials fabricated in close thermal contact with a substrate having high thermal conductivity. This allows for bombardment of the targets with higher electron density or higher energy electrons, which leads to greater x-ray brightness and therefore greater x-ray flux.
The high brightness/high flux source may then be coupled to an x-ray reflecting optical system, which can focus the high flux x-rays to a spots that can be as small as one micron, leading to high flux density.

First claim

We claim:

1 . An x-ray system for analyzing a specimen, comprising:
at least one x-ray source comprising: a plurality of x-ray generating sub-sources, in which
each of the x-ray generating sub-sources
has a source size less than 20 micrometers in at least one direction,

and is aligned along a predetermined axis
so that x-rays generated from
at least two of the plurality of x-ray generating sub-sources accumulate within a predetermined divergence angle relative to the predetermined axis; and

additionally comprising:
an x-ray optical system
having an optical axis aligned relative to the predetermined axis,

said optical system positioned to collect diverging x-rays accumulated from said at least two of the plurality of the of x-ray generating sub-sources in the x-ray source
and to condition and create an x-ray beam with predetermined properties;
said optical system additionally comprising a central beam stop positioned to block x-rays propagating parallel to the optical axis;
a means to direct the x-ray beam to be incident
with a grazing angle of less than 5 degrees
onto an area of a surface of a specimen;

at least one detector
which detects the intensity of the x-rays emerging from the specimen and generates electrical signals; and
a signal processor to analyze the electrical signals
to obtain information about at least one of:
composition, concentration, quantity, and film thickness.

2 . The x-ray system of claim 1 ,
in which said at least one detector is positioned
to detect x-rays that are diffracted by the specimen;
and additionally comprising: at least one additional detector to detect x-rays reflected
from the surface of the specimen.

3 . The x-ray system of claim 1 , in which
said predetermined axis and said optical axis are coincident.

4 . The x-ray system of claim 1 , in which
said optical system comprises a total external reflection based x-ray optic, and said predetermined divergence angle is determined in part
based on the critical angle of said x-ray optic.

5 . The x-ray system of claim 1 , in which
said predetermined divergence angle is determined in part
based on the total length along the optical axis of the x-ray generating region.

6 . The x-ray system of claim 1 , in which
said x-ray beam with predetermined properties has the property of being focused to a single spot with a spot size smaller than 300 microns; and in which the focused x-ray spot corresponds to a predetermined position on the surface of the specimen.

7 . An x-ray measurement system, comprising:
an x-ray source, comprising: one electron beam emitter; and one anode target comprising:
a substrate comprising a first selected material,
in which said substrate has at least one planar surface; and

a plurality of discrete structures aligned along a predetermined axis comprising a second material selected for its x-ray generation properties;
in which each of the plurality of discrete structures
is in thermal contact with the substrate; and

in which at least two of the discrete structures
have at least one dimension parallel to said planar surface
of less than 20 microns; and additionally comprising:

an electron beam control system to direct electrons from the electron beam emitter onto the plurality of discrete structures; an optical train having an optical axis to collect diverging x-rays generated
by said at least two of the plurality of discrete structures in the anode target, and that produces an x-ray beam with predetermined beam properties;
said optical train additionally comprising a central beam stop
positioned to block x-rays propagating parallel to said optical axis;
a mount to hold an object to be investigated,
positioned such that the x-ray beam will be incident on the object
at a grazing angle of less than 5 degrees; and

a detector to measure x-rays emerging from the object
when x-rays are incident on the object.

8 . The system of claim 7 , in which
said detector is positioned
to detect x-rays that are diffracted by the specimen;
and additionally comprising: an additional detector to measure the intensity
of the x-rays reflected from the object.

9 . The system of claim 7 , in which
each dimension parallel to said at least one planar surface
of said at least two of the discrete structures
is less than 50 microns.

10 . The system of claim 7 , in which
the plurality of discrete structures are arranged in a linear array along said predetermined axis; and the optical axis of the optical train is also aligned along said predetermined axis.

11 . The system of claim 7 , in which
the first selected material is selected from the group consisting of: beryllium, diamond, graphite, silicon, boron nitride, silicon carbide, sapphire and diamond-like carbon.

12 . The system of claim 7 , in which
the second material is selected from the group consisting of: aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, gallium, zinc, yttrium, zirconium, molybdenum, niobium, ruthenium, rhodium, palladium, silver, tin, iridium, tantalum, tungsten, indium, cesium, barium, gold, platinum, lead and combinations and alloys thereof.

13 . The system of claim 7 , additionally comprising:
an additional plurality of discrete structures aligned along said predetermined axis comprising a third material selected for its x-ray generation properties, in which each of the additional plurality of discrete structures
is in thermal contact with the substrate, and
in which at least two of the additional discrete structures
have at least one dimension parallel to said planar surface
of less than 20 microns.

14 . The system of claim 13 , in which
the third material is selected from the group consisting of: aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, gallium, zinc, yttrium, zirconium, molybdenum, niobium, ruthenium, rhodium, palladium, silver, tin, iridium, tantalum, tungsten, indium, cesium, barium, gold, platinum, lead and combinations and alloys thereof.

15 . The system of claim 7 , in which
the plurality of discrete structures are arranged such that x-rays generated by a predetermined number of the plurality of discrete structures when exposed to an electron beam from the electron beam emitter are transmitted through a predetermined one of the discrete structure
selected from the plurality of discrete structures.

16 . The system of claim 7 , in which
the anode target is mounted such that the anode target may rotate about an axis.

17 . The system of claim 16 , in which
the electron beam control system that direct electrons from the electron beam emitter onto the plurality of discrete structures is adjusted to direct electrons only onto a region of the anode target comprising a portion of the plurality of x-ray generating structures that is aligned with the optical train.

18 . The system of claim 7 , comprising
an additional number of electron emitters and, an additional number of anode targets, with each anode target corresponding to a single electron emitter, such that each electron emitter is aligned to provide an electron beam to bombard the corresponding anode target to generate x-rays; and the additional number of anode targets are aligned
with each other and with said one anode target, such that
the positions at which x-rays are generated
in said one anode target and said additional number of anode targets are al

Assignees

• Sigray Inc

Inventors

• Yun Wenbing
• Lewis Sylvia Jia Yun
• Kirz Janos

Classifications

• G01N23/201

  by measuring small-angle scattering · CPC title

• G01N23/205 Primary

  using diffraction cameras · CPC title

• G01B15/02

  for measuring thickness · CPC title

• G01N23/2076

  for spectrometry, i.e. using an analysing crystal, e.g. for measuring X-ray fluorescence spectrum of a sample with wavelength-dispersion, i.e. WDXFS · CPC title

• G21K1/062

  Devices having a multilayer structure · CPC title