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US 9,177,760 B2Granted
TEM sample preparation
AssigneeFEI Company
InventorsJeffrey Blackwood, Matthew Bray, Corey Senowitz, Cliff Bugge
Life of this patent
Estimating the term…
Abstract
An improved method of preparing ultra-thin TEM samples that combines backside thinning with an additional cleaning step to remove surface defects on the FIB-facing substrate surface. This additional step results in the creation of a cleaned, uniform “hardmask” that controls the ultimate results of the sample thinning, and allows for reliable and robust preparation of samples having thicknesses down to the 10 nm range.
Claims13
A method of preparing a sample for TEM analysis, the method comprising:
- loading a substrate into an ion beam system;
- separating a sample from the substrate by ion beam milling;
- extracting the sample from the substrate, said sample having a vertical axis, a top side, and a bottom side;
- attaching the sample to a sample holder;
- positioning the sample holder before thinning the sample, so that the ion beam is transverse to the vertical axis of the sample;
- positioning the sample holder so that the bottom side of the sample is oriented toward the ion beam source and so that the ion beam is parallel to the vertical axis of the sample;
- milling the bottom side of the sample to remove at least of portion of the bottom surface of the sample to produce a uniformly flat surface;
- and
- thinning the sample by directing the ion beam in a milling pattern that thins at least a portion of the sample to electron transparency.
6 more elements
A method of preparing an ultra thin TEM sample for TEM analysis, the method comprising:
- loading a substrate into an ion beam system including an ion beam source and optics for focusing an ion beam along an axis and onto the substrate;
- freeing a sample from the substrate by ion beam milling, said sample having a vertical axis, a top side closest to the ion beam source, and a bottom side opposite the ion beam source;
- attaching a microprobe to the freed sample;
- extracting the sample from the substrate using the attached microprobe;
- inverting the sample by rotating the microprobe so that the orientation of the top and bottom sides is reversed;
- attaching the inverted sample to a sample holder and separating the microprobe from the attached sample;
- positioning the sample holder so that the ion beam axis is at an angle of 30 to 90 degrees relative to the vertical axis of the sample;
- removing at least 25 nm from the bottom of the sample to produce a planar surface parallel to the ion beam axis;
- positioning the sample holder so that the top side of the sample is oriented opposite the ion beam source and so that the ion beam axis is parallel to the vertical axis of the sample;
- thinning the sample by directing the ion beam in a milling pattern that thins at least a portion of the sample to electron transparency.
7 more elements
An apparatus for preparing ultra-thin TEM sample comprising:
- an ion beam system including an ion beam source, optics for focusing an ion beam along an axis and onto a substrate, and a micromanipulator for manipulating a sample;
- and
- a computer-readable memory storing computer instructions, the instructions including a program for controlling the apparatus and causing the apparatus to carry out the steps of:
- locating a desired sample site on the substrate;
- separating a sample from the substrate by ion beam milling;
- extracting the sample from the substrate, said sample having a vertical axis, a top side, and a bottom side;
- attaching the sample to a sample holder;
- positioning the sample holder so that the ion beam is transverse to the vertical axis of the sample;
- milling the bottom side of the sample to remove at least of portion of the bottom surface of the sample to produce a uniformly flat surface;
- positioning the sample so that the bottom side of the sample is oriented toward the ion beam source and so that the ion beam is parallel to the vertical axis of the sample;
- and
- thinning the sample by directing the ion beam in a milling pattern that thins at least a portion of the sample to electron transparency.
9 more elements
Dependencies are inferred from the claim text.