US4962306A — Magnetically filtered low loss scanning electron …

Claim 1

Independent Claim 68 words

An electron apparatus including, in combination: means for producing an electron beam, means for directing said beam to a sample to be examined, means for producing a magnetic field in which said sample is immersed, and a detector for detecting electrons scattered from said sample, said detector being located in said magnetic field at a location such that only low-loss electrons scattered from said sample reach said detector.

Claim 2

Dependent Claim 68 words

An electron apparatus including, in combination: means for producing an electron beam, means for directing said beam to a sample to be examined, means for producing a magnetic field in which said sample is immersed, and a detector for detecting electrons scattered from said sample, said detector being located in said magnetic field at a location such that only low-loss electrons scattered from said sample reach said detector.

Claim 3

Dependent Claim 22 words

The apparatus of claim 1, where said low-loss electrons have an energy within 5% of the energy of electrons in said beam.

Claim 4

Dependent Claim 13 words

The apparatus of claim 2, where said microscope is a scanning electron microscope.

Claim 5

Dependent Claim 17 words

The apparatus of claim 1, where said means for producing a magnetic field is a condenser-objective lens.

Claim 6

Dependent Claim 18 words

The apparatus of claim 1, where said sample is located in a high-field region of said magnetic lens.

Claim 7

Dependent Claim 18 words

The apparatus of claim 5, where said detector is located in a high-field region of said magnetic lens.

Claim 8

Dependent Claim 17 words

The apparatus of claim 1, further including scanning means for scanning said electron beam across said sample.

Claim 9

Dependent Claim 29 words

The apparatus of claim 1, where said detector has a curved electron collecting surface substantially matching the envelope of the trajectories of said low-loss electrons in said magnetic field.

Claim 10

Dependent Claim 28 words

The apparatus of claim 1, including a plurality of detectors arranged in position substantially along the envelope of the trajectories of said low-loss electrons in said magnetic field.

Claim 11

Dependent Claim 17 words

The apparatus of claim 1, where said sample and said detector are attached to a single holder.

Claim 12

Dependent Claim 16 words

The apparatus of claim 10, further including means for moving said detector relative to said holder.

Claim 13

Dependent Claim 33 words

The apparatus of claim 1, including a plurality of detectors having curved surfaces, the curved surfaces being substantially in a shape determined by the envelope of the trajectories of the scattered low-loss electrons.

Claim 14

Dependent Claim 26 words

The apparatus of claim 1, where said low-loss electrons scattered from said sample have energies within about 1% of the energies of electrons in said beam.

Claim 15

Dependent Claim 59 words

In an electron microscope having a sample to be examined located within a focussing magnetic field and means for scanning an electron beam across said sample, the improvement comprising a detector for collecting low-loss electrons scattered from said sample, said detector being located at a position in said magnetic field intercepted only by the trajectories of scattered low-loss electrons.

Claim 16

Dependent Claim 59 words

In an electron microscope having a sample to be examined located within a focussing magnetic field and means for scanning an electron beam across said sample, the improvement comprising a detector for collecting low-loss electrons scattered from said sample, said detector being located at a position in said magnetic field intercepted only by the trajectories of scattered low-loss electrons.

Claim 17

Independent Claim 95 words

An apparatus, including: means for producing a beam of charged particles, means for directing said beam of charged particles to a sample to be examined, means for producing a focussing electromagnetic field in which said sample is immersed, and a detector for detecting charged particles scattered from said sample, said detector being located in a position in said electromagnetic field such that the envelope of the trajectories of charged particles, scattered from said sample with essentially the same energy as the charged particles incident upon said sample are tangent to a surface of said detector.

Claim 18

Independent Claim 95 words

An apparatus, including: means for producing a beam of charged particles, means for directing said beam of charged particles to a sample to be examined, means for producing a focussing electromagnetic field in which said sample is immersed, and a detector for detecting charged particles scattered from said sample, said detector being located in a position in said electromagnetic field such that the envelope of the trajectories of charged particles, scattered from said sample with essentially the same energy as the charged particles incident upon said sample are tangent to a surface of said detector.

Claim 19

Dependent Claim 54 words

The apparatus of claim 15, where said detector has a curved surface for collecting said scattered charged particles, said curved surface having a shape corresponding to the envelope of the trajectories of charged particles scattered from said sample with essentially the same energies as the energies of the charged particles incident upon said sample.

Claim 20

Dependent Claim 28 words

The apparatus of claim 15, including a plurality of detectors being located so that the charged particle collecting surfaces of said detectors are substantially tangential to said trajectories.

Claim 21

Dependent Claim 34 words

The apparatus of claim 15, where said detector is comprised of a scintillator material, said scintillator material being adjacent to a light guide for conducting light produced by charged particles striking said scintillator material.

Claim 22

Dependent Claim 12 words

The apparatus of claim 15, where said detector is a semiconductor detector.

Claim 23

Dependent Claim 30 words

The apparatus of claim 15, including a plurality of detectors for collecting said charged particles scattered from said sample, said detectors being comprised of scintillator detectors connected to light pipes.

Claim 24

Dependent Claim 19 words

The apparatus of claim 15, where said detector is comprised of a scintillator material coated on an optical fiber.

Claim 25

Dependent Claim 34 words

The apparatus of claim 21, where the center of said optical fiber protrudes beyond a surface determined by said envelope of trajectories, the edges of said optical fiber being outside said envelope of trajectories.

Claim 26

Independent Claim 113 words

A method for analyzing a sample with a beam of charged particles, including the following steps: immersing a sample in an electromagnetic field, producing a beam of charged particles, directing said beam to said sample, collecting charged particles having a first energy range or scattering angle which are scattered from said sample to a detector located at a first position in said electromagnetic field, the trajectories of said scattered charged particles being determined by their energies after striking said sample and by said electromagnetic field, and moving said detector to a second location in said electromagnetic field to collect charged particles scattered from said sample at a second energy range or scattering angle.

Claim 27

Independent Claim 113 words

A method for analyzing a sample with a beam of charged particles, including the following steps: immersing a sample in an electromagnetic field, producing a beam of charged particles, directing said beam to said sample, collecting charged particles having a first energy range or scattering angle which are scattered from said sample to a detector located at a first position in said electromagnetic field, the trajectories of said scattered charged particles being determined by their energies after striking said sample and by said electromagnetic field, and moving said detector to a second location in said electromagnetic field to collect charged particles scattered from said sample at a second energy range or scattering angle.

Claim 28

Dependent Claim 19 words

The method of claim 23, where said charged particles are electrons and said electromagnetic field is a magnetic field.

Claim 29

Dependent Claim 18 words

The method of claim 24, where said sample is located in a high-field region of said magnetic field.

Claim 30

Dependent Claim 32 words

The method of claim 23, where said detector is moved in said electromagnetic field, the positions of said detector being determined by the scattering angles of charged particles scattered from said sample.

Claim 31

Independent Claim 98 words

An apparatus for examining a sample, including: means for producing a beam of charged particles, means for directing said beam to a sample, field means for producing a field for focussing said beam of charged particles, the trajectories in said field of charged particles scattered from said sample being determined by the energies of said scattered charged particles and by said field, and detector means located in said field at a position where the charged particles striking said detector after scattering from said sample are those which have essentially the same energy as charged particles in said beam.

Claim 32

Independent Claim 98 words

An apparatus for examining a sample, including: means for producing a beam of charged particles, means for directing said beam to a sample, field means for producing a field for focussing said beam of charged particles, the trajectories in said field of charged particles scattered from said sample being determined by the energies of said scattered charged particles and by said field, and detector means located in said field at a position where the charged particles striking said detector after scattering from said sample are those which have essentially the same energy as charged particles in said beam.

Claim 33

Dependent Claim 36 words

The apparatus of claim 27, where said detector has a flat conducting surface placed tangentially to the envelope of the trajectories of said scattered charged particles, said conducting surface being connected to a current measuring device.

Claim 34

Dependent Claim 29 words

The apparatus of claim 27, where said detector has a conducting surface curved substantially in a shape determined by the envelope of the trajectories of said scattered charged particles.

Claim 35

Dependent Claim 12 words

The apparatus of claim 27, where said detector is a semiconductor detector.

Claim 36

Dependent Claim 30 words

The apparatus of claim 30, where the surface of said semiconductor detector is curved substantially in a shape determined by the envelope of the trajectories of said scattered charged particles.

Claim 37

Dependent Claim 44 words

The apparatus of claim 27, where said detector is comprised of a scintillator material, the surface of said scintillator material being substantially tangent to the envelope of the trajectories of said scattered charged particles, said scintillator surface being connected to a light measuring device.

Claim 38

Dependent Claim 23 words

The apparatus of claim 32, where said scintillator is connected to a light pipe which conducts light from the scintillator to a photodetector.

Claim 39

Dependent Claim 35 words

The apparatus of claim 27, where said detector is a scintillator detector having a curved surface, said surface being curved to a shape determined by the envelope of the trajectories of said scattered charged particles.

Claim 40

Dependent Claim 43 words

The apparatus of claim 27, where said detector is located at a position such that its collecting surface is substantially tangent to the trajectories of charged particles scattered from said sample with essentially the same energy as the charged particles in said beam.

Claim 41

Dependent Claim 43 words

The apparatus of claim 27, where said detector is a scintillator located over the center of an optical fiber, the end of said optical fiber being positioned substantially on a surface determined by the envelope of the trajectories of said scattered charge particles.

Claim 42

Dependent Claim 22 words

The apparatus of claim 27, including a plurality of detectors formed by a scintillator material coated on an array of optical fibers.

Claim 43

Dependent Claim 37 words

The apparatus of claim 37, where said fibers have a central portion which protrudes beyond a surface determined by the envelope of the trajectories of said scattered charged particles, said trajectories being substantially tangent to said surface.

Claim 44

Dependent Claim 24 words

The apparatus of claim 27, where said detector has a conducting surface placed at an angle to the trajectories of said scattered charged particles.

Claim 45

Dependent Claim 43 words

The apparatus of claim 39, where said conducting surface has an edge curved substantially in a shape matching the envelope of the trajectories of said scattered charged particles, the envelope of said trajectories being substantially tangent to the curved edge of said detector.

Claim 46

Dependent Claim 16 words

The apparatus of claim 27, where said beam of charged particles is a beam of electrons.

Claim 47

Dependent Claim 20 words

The apparatus of claim 40, where the means for producing a beam of charged particles is a scanning electron microscope.

Claim 48

Dependent Claim 22 words

The apparatus of claim 40, where said means for producing a beam of charged particles is a scanning transmission electron microscope (STEM).

Claim 49

Dependent Claim 21 words

The apparatus of claim 40, where said means for producing a beam of charged particles is a transmission electron microscope (TEM).

Claim 50

Dependent Claim 21 words

The apparatus of claim 40, where said means for producing a beam of charged particles is a scanning tunneling microscope (STM).

Claim 51

Dependent Claim 21 words

The apparatus of claim 39, where said means for producing a beam of charged particles is an atomic force microscope (AFM).

Claim 52

Dependent Claim 25 words

The apparatus of claim 1, where said low-loss electrons have minimum energies at least about 50% of the energy of the electrons in said beam.

Claim 53

Dependent Claim 31 words

The apparatus of claim 14, where said scattered low-loss electons have energies greater than about 50% of the energies of electrons in said electron beam that is scanned across said sample.

Claim 54

Dependent Claim 31 words

The apparatus of claim 15, where the minimum energy of charged particles scattered from said sample is about 50% of the energy of charged particles in said beam of charged particles.

Claim 55

Dependent Claim 31 words

The apparatus of claim 27, where the minimum energy of charged particles scattered from said sample is about 50% of the energy of charged particles in said beam of charged particles.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-10-08	1994-04-09	1994-10-09	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-10-08	1998-04-09	1998-10-09	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-10-08	2002-04-09	2002-10-09	$7700.00	Window Closed / Lapsed

Magnetically filtered low loss scanning electron microscopy

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