SPM, AFM, SEM Calibration Standards

Magnification Reference Standards - SPM, AFM, SEM Calibration Standards

EMS offers a series of calibration standards with one and two dimension calibrated patterns. The standards come in two grid spacings – 300 nanometers and 700 nanometers. These standards
are created utilizing holographic interference of a particular laser frequency. They are typically accurate to <1% across the entire surface of the standard.

White area material: Tungsten.
Black area material: Tungsten, or other metal.

Materials:
The calibration specimen consists of a silicon chip with a thin (100nm) thick polymer layer containing the pattern and a thin tungsten film over-coating the entire surface. The tungsten film varies from 20nm to 60nm in thicknenss, depending on the particular model. This structure has been proven under a wide varitey of beam conditions,
from 30kV to sub 12 kV.

Dimensions:
300nm or 700nm nominal (exact dimension will be provided with sample). Measurements are made from leading edge to leading edge, etc. Width of individual bars and spaces is not calibrated.

Background

EMS MXS "CE" and "BE" series SEM magnification reference gratings and grids set new standards for sub-micron accuracy and ease-of-use. Designed to meet the requirements for a reasonable cost, accurate sub-micron reference standard, "CE" Series Reference Standards can be tailored to meet a variety of needs.

• They are ideal for student practice and instruction, testing new ideas or applications, or other uses where you need a good quality standard but do not want to put an expensive sample at risk.
• Exceptional accuracy, repeatability, and uniformity are assured since each individual standard is an original or master produced directly from a holographic interference pattern.

These reference standards are remarkably durable under typical operating conditions. The surface contamination behavior is also very good. There are no better sub-micron reference standard available in this price range.

One test site indicated that on a scale of 1 to 5 with respect to ease of use, contrast/brightnes, durability, and accuracy, "CE" series reference standards earn a 4.7 out of 5 average in comparison to other available standards. Comments from various other test sites included "very good contrast/brightness levels at all voltages used," "easy to use," and "could become my secondary standard of choice."

Application

EMS's MXS "CE" series reference standards provide a calibrated dimension of either 300 nm or 700 nm nominal length. ("BE" series available only 300 nm)

• The larger dimension provides accurate, multiple period measurement from about 5000X to over 45,000X while
• the smaller dimension is useful from about 10,000X to over 100,000X.

Throughout this magnification range, these standards provide excellent image contrast, an enormous useful calibration area, and a 3-sigma accuracy of at worst 3%, with typical values around 1%.

MXS "CE" and "BE" series reference standards are available as unmounted 3 mm x 4 mm pieces to be mounted by the microscopist, or pre-mounted for easy insertion in your SEM. Mounting one of these calibration standards is striaghtforward. The front surface of the sample and the silicon substrate are conductive. Experience indicates that there is, in general, no need to make a special effort to ground the front surface. The use of conductive silver or carbon-loaded paint, conductive epoxies, conductive tape, etc. have all been used to successfully mount "CE" Series standards.

With EMS's MXS "CE" and "BE" Series Reference Standards, you can:

• Quickly check dimensional measurements by mounting one on your specimen stage.
• Perform periodic calibration and performance checks of your microscope.
• Obtain high magnification, sub-micron-scale dimensional accuracy for the first time.
• Accurately determine dimensions from 0.3 µm to 30 µm all with one calibration artifact.
• Analyze your images for pin-cushion distortion, small-scale vibration, or small magnetic field distortions.

The accuracy of the "CE" Series Reference Standards, allows the microscopist to use them as a secondary standard. Their accuracy and uniformity make it easy to obtain and document traceability of measurements without placing an expensive, hard to obtain, difficult to use primary calibration standard at risk of contamination or damage.

Certification and Accuracy

MXS "CE" Series Reference Standards provide a calibrated dimension of either 300 nm or 700 nm nominal length. The actual dimension of the artifact as delivered will generally not be exactly these values. Both the fabrication process determines the actual dimension and by a second, independent measurement after the calibration artifact is manufactured.

The expected accuracy of the holographic technique used in the manufacturing process is ±0.1%. Unfortunately, subsequent processing steps degarde this initial accuracy, leading to the 3-sigma accuracy of 3% for the finished product. The second, independent measurement technique has an expected 3-sigma accuracy of 1% or better. Our experience is that the two measurement techniques applied to a particular artifact will agree with each other within 0.5mm.

It is important to remember that the certified dimension in an MXS "CE" and "BE" Series Reference Standard is not just at one unique position on the artifact, but is known at all locations on the standard.

Durability and Charging Effects

EMS MXS "CE" and "BE" Series Reference Standards have been tested and evaluated over a broad range of operating conditions, from those found in a tungsten filament system to the highest resolution FEG system. These standards have been found remarkably durable during use, with no beam-induced distortion in the calibrated pattern after as much as one-half hour of imaging time at 50,000X and 20 KV. Charging is minimal to non-existent, though edge-effect can be seen under some conditions. The high contrast and brightness, which can be obtained using these reference standards guarantees good contamination tolerance.

1. MXS 301CE and MXS 701CE

The calibrated dimension is the spatial period of a series of parallel ribs running across the surface of the sample. The significant height of the ribs (>100 nm) provides excellent image contrast. The top surface of the rib structures is somewhat rounded rather than completely flat. The edges of the ribs are readily discernible, with over 75% of the 3 mm by 4 mm sample area exhibiting an edge location variation, which is less.

Use and Imaging

The exceptionally clean and uniform pattern provided in an MXS 301CE or MXS 701CE standard displays few imperfections, which can be used as focusing and stigmation aids. For this reason, care in setting up the image before measurement is important. To assist in the setup process, an instruction sheet is provided with each standard. This sheet provides several example images, which can be used to determine if the image of the sample is correctly set up. Expecially with the MXS 301CE and MXS 701CE line-space pattern standards, obtaining the proper stigmation is crucial since improper stigmation is not readily apparent when imaging a pattern of straight line. Once a proper focus and sigmation are obtained, the image can be shifted to an appropriate area and the desired measurements made.

2. MXS 302CE and MXS 702CE

The calibrated dimension is the spatial period of a series of a 2-dimensional grid spread across the surface of the sample. This grid consists of a series of cylindrical posts rising from the surface of the sample. The significant height of the ribs (>100 nm) provides excellent image contrast. The top surface of these posts is somewhat rounded rather than flat and there are also slight departures from a perfect circle in the shape of some posts. Measurement techniques must be used which take these characteristics into account. The center-to-center distance of any pair is the most accurate measurements.

Use and Imaging

The exceptionally clean and uniform pattern provided in an MXS "CE" series 2-dimensional calibration standard displays few large scale imperfections which can be used as focusing and stigmation aids. For this reason, taking care in setting up the image before measurement is important. To assist in this process, an instruction sheet is provided with each standard. This sheet provides several example images which can be used to determine if the image of the sample is correctly set up.

The characteristics of the MXS 302CE and MXS 702CE standards make them easier to image than the 1-dimensional standards. The 2-dimensional grid facilitates setting the stigmation of the image properly. Once proper focus and sigmation are obtained, the image can be shifted to an appropriate area and the desired measurements made.Since the pattern covers the entire sample area, it is possible to make over 1,000,000 measurements utilizing the standard without using the same area twice.

Cleaning for the CE Series

Cleaning is possible using dry air or other clean gases, high purity distilled or deionized water, and soft brushes. Rubbing with soft tissues, or any other firm physical contact, or the use of solvents such as acetone or alcohol will damage the surface of the reference standard.

3. MXS 301BE

The calibrated dimension is the spatial period of alternating lines of Titanium and Silicon. The use of two different elements provides excellent image contrast, and the titanium layer thickness is kept to 20 nm to control edge distortion effects in the SEM image. These physical characteristics make the edges sharp and readily discernable. The calibrated pattern covers the entire sample, providing over 1,000,000 measurement sites. Because the pattern is a direct recording of a laser-generated interference pattern which has been transferred into the 20 nm thick Titanium film, these calibration samples are the most accurate available.

Imaging and Application

The exceptionally clean and uniform pattern provided in a MOXTEX MXS "BE" series calibration standard displays few imperfections which can be used as focusing and stigmation aids. For this reason, care in setting up the image before measurement is important. To assist in this process, an instruction sheet is provided with each standard. This sheet provides several example images which can be used to determine if the image of the sample is correct. Once a proper focus and stigmation are obtained, the image can be shifted to an appropriate area and the desired measurements made.

The full screen image provided by a MOXTEX calibration sample provides a unique advantage. Most calibration standards really verify accuracy of one portion of the image, while the entire screen is part of the measurement tool. With an image that fills the screen, you can quickly diagnose all types of image distortions, including problems due to vibrations, external fields, etc. A common problem is distortion caused by missadjusted CRT's or scanners in which the magnification in one part of the image is different from another part of the image. Such problems are easily found and corrected using these calibration samples.

Cleaning for the BE Series

Titanium on Silicon produces a very durable calibration pattern. The calibration standard can be cleaned using common solvents such as acetone or alcohol, detergents, deionized water, etc. Gentle physical rubbing with soft tissues, brushes, etc., should not damage the sample. In extreme cases, cleaning by oxygen plasma may be possible.

Product Data

	301CE & 701CE	302CE & 702CE	301BE**
Substrate	Silicon Wafer	Silicon Wafer	Silicon Wafer
Top Surface	60 nm Tungsten film	60 nm Tungsten film	Ti pattern on Si
Physical Size	3mm x 4mm x 0.5mm	3mm x 4mm x 0.5mm	3mm x 4mm x 0.5mm
Accuracy	± 3%	± 3%	± 1%
Nominal Dimensions	(x)	(x, y)	(x)
	300 nm for 301CE	300 nm for 302CE	300 nm for 301BE
	700 nm for 701CE	700 nm for 702CE
Availability	mounted or unmounted*	mounted or unmounted*	mounted or unmounted*

*The cost for mounted samples using standard aluminum pin type stubs (EMS #75200). Please call us for additional expense.

**MXS-301BE Calibration sheet provided with standard contains actual dimensions to 3 significant figures. NPL tracability is also available with an additional cost.

Appli-cation	Product	Pattern	Material	Nominal Pitch	Mounting	Product No.	Price	Cart
SEM	701CE	Parallel Ridges	W-coated Photoresist on Si	700 nm	unmounted	80110-71	318.00
					mounted	80110-71M	418.00
SEM	301CE	Parallel Ridges	W-coated Photoresist on Si	300 nm	unmounted	80110-31	424.00
					mounted	80110-31M	524.00
SEM	702CE	Array of Posts	W-coated Photoresist on Si	700 nm	unmounted	80110-72	636.00
					mounted	80110-72M	736.00
SEM	302CE	Array of Posts	W-coated Photoresist on Si	300 nm	unmounted	80110-32	848.00
					mounted	80110-32M	948.00
AFM, SEM, TOF-SIMS, Auger, etc.	301BE	Parallel Ridges	Ti lines on silica	300 nm	unmounted	80111-31	1,060.00
					mounted	80111-31M	1,160.00

Special Services (Needs to be added to the standard price)

SS-301	301BE Certification		2,650.00
SS-SEM	Mount Certified Specimen for SEM		212.00

SPM CALIBRATOR

Improve the accuracy of your SPM measurements using SPM Calibrator, the new standard for image accuracy.

The Problem:

Effective process controls depends on accurate dimensional measurements. Quality assurance requires fast, thorough calibration checks.

The Solution:

SPM Calibrator is a new system for calibrating scanning probe microscopes. It can help you improve the accuracy of critical dimension measurements and makes QC testing of your SPM easier.

Ordinary SPM scans may be accurate only to 5%. This can make it hard to judge whether device dimensions actually meet specifications.

SPM Calibrator consists of a reference standard and data analysis software. The output shows you how accurate your SPM is. Every SPM user benefits from the convenience of well documented calibration checks. You can improve the accuracy of your existing SPM, guided by the results from SPM Calibrator.

WHY SETTLE FOR 5% ACCURACY WHEN YOU CAN HAVE 0.5%?

Product Description

Overall Benefits:

• Easier testing of your SPM.
• Improved accuracy of critical dimension measurements.
• Accuracy: 0.5% (1 std. dev.).

Features and Benifits:

• Holographic fabrication - assures high accuracy and precision.
• Pattern height > 100nm - provide excellent image contrast.
• Uniform coverage of entire chip - save time (can image anywhere).

Description:

• Nominal calibrated dimensions: 300 or 700 nm.
• Calibration certificate: supplied with each sample, stating the dimension to the nearest 1 nm.
• Pattern types: 1- or 2—Dimensional. The calibrated dimension is the same for both axes for the 2-D standard.
• Feature geometry:
  -parallel ridges (1-D, 300 or 700nm)
  -cylindrical posts (2-D 300nm)
  -diamond-shaped posts (2-D 700nm)
• Physical Size: 3 mm x 4 mm x 0.5mm.
• Substrate: Silicon wafer.
• Top surface: Tungsten film.

The 1-D standards can be scanned using any AFM mode, including contact mode. The 2-D standards can be scanned using modes such as Tapping Mode™, intermittent contact, and non-contact.

Recent Additions:
Model 150-1D

Accurate measurements of sub 0.5 micron features are increasingly important as nanotechnology develops and as conventional microfabricated structures (semiconductors, magnetic data storage devices, optical data discs) shrinking. The model 150-1D with a nominal period (pitch) of 150nm, one dimensional, fabricated on a transparent substrate (Aluminum lines on glass) is the new tool to support this work.

Model 750-HD

High Durability Calibration Reference Specimen for AFM and STM

Each specimen is supplied with a calibration certificate.Can be used for ATM, STM and SEM. Has been used successfully in a hot water AFM.

Nominal pattern dimensions:	Pitch 750 nm
	Height 100 nm
Nominal specimen dimensions:	6.35 mm diameter, 0.3 mm thick
Composition:	Solid Nickel

Model PT

Phase Imaging Test Specimen (verify TappingMode™ phase contrast and resolution).

Phase Imaging is a sharp probe, which is brought into proximity with the specimen surface. The probe is oscillated vertically near its mechanical resonance frequency. As the probe lightly taps the surface the amplitude of oscillation is reduced and the AFM uses this change in amplitude in order to track the surface topography. In addition to its amplitude, the probe motion can be characterized by its phase relative to a driving oscillator. The phase signal changes when the probe encounters regions of different composition. Phase shifts are registered as bright and dark regions in phase images, comparable to the way height changes are indicated in height images.

Phase images often show extraordinary contrast for many composite surfaces of technological and scientific interest. These include contamination deposits, discontinuous (i.e. defective) thin films devices built of composite materials (e.g. magnetic recording heads), and cross-sectional specimens of composite materials. Both inorganic and organic materials can be examined. We have found that phase imaging is more convenient and gentler than other methods, which are based on contact mode operation. It routinely achieves lateral resolution of 10 nm.

References

1.Pereira, D.E.D. & Claudio-da-Silva, Jr., E. "Improvement of AFM as an analytical Instrument for Residual Lignin Characterization" in: Proceedings International Symposium on Wood and Pulping Chemistry, Helsinki, Finland, June 1995.

2.Pereira, D.E.D., Chernoff. D., & Claudio-da-Silva, Jr.,E., & Cemuner, B.J„ "The use of AFM to investigate the delignificalion process: Part 1-AFM performance by differentiating pulping processes", to be published.

Ordering for Calibrator only

Product No.	Appli-cation	Product	Pattern	Material	Nominal Pitch	Mounting	Price	Cart
80122-1D	AFM	700-1D	Parallel ridges	W-coated Photoresist on Si	700 nm	15mm steel disk	371.00
80123-1D	AFM	300-1D	Parallel ridges	W-coated Photoresist on Si	300 nm	15mm steel disk	477.00
80122-2D	AFM	700-2D	Array of posts	W-coated Photoresist on Si	700 nm	15mm steel disk	742.00
80123-2D	AFM	300-2D	Array of posts	W-coated Photoresist on Si	300 nm	15mm steel disk	954.00
80124-HD	AFM, SEM	750-HD	Array of Flat Bumps	Ni	750(X), Z(100)	un-mounted	265.00
80124-EDU	AFM, SEM	302-EDU	Array of Posts	W-coated Photoresist on Si	300 nm	un-mounted	371.00
80124-PT	AFM Phase Imaging	PT	Random hard & soft domain as small as 10nm	Polymer	None	15 mm steel Disk	159.00
80125-1D	AFM, SEM, TOF-SIMS, Auger, etc.	150-1D	Parallel ridge	A1 Lines on Glass	150	un-mounted	583.00

 

Model 150-2D — Very High Reference and Traceable Standard for Resolution Calibration AFM, SEM, Auger, and FIB

General Purpose – High Precision

A precision, holographic pattern provides accurate calibration in the horizontal plane for very high resolution, nanometer-scale measurements.

Period: 144 nm pitch, two-dimensional array. Accurate to ± 1 nm. Refer to calibration certificate for actual pitch.

Surface: Aluminum bumps on Silicon, 4x3 mm die. Bump height (about 90 nm) and width (about 75 nm) are not calibrated.

For AFM, use in contact, intermittent contact (TappingMode™) and other modes with image sizes from 250 nm to 10 mm. Available un-mounted or mounted on 12 mm steel disks.

For SEM, an independent analytical lab has tested this specimen in a FE-SEM (field emission scanning electron microscope). They found that the pattern was very uniform and the specimen was easy to image. No significant charging was observed in the voltage range 1- 20 kV.

Usability: the calibrated pattern covers the entire chip. There is sufficient usable area to make tens of thousands of measurements without reusing any areas altered or contaminated by previous scans.

MODEL 150-2D:

This Calibration Reference specimen comes with a nontraceable, manufacturer’s certificate. These states the average period, based on batch measurements.

MODEL 150-2DUTC:

This traceable, Certified Standard is a select grade. Each standard is individually measured in comparison with a similar specimen calibrated at PTB. (PTB, Physikalisch- Technischen Bundesanstald, is the German counterpart of NIST). The uncertainty of single pitch value is typically
±1,4 nm (95% confidence interval). Multi-pitch measurements provide the usual square-root of N improvement in precision.

Easy to use

We recommended Model 150-2D because of its unique characteristics which make it especially easy to use. The specimen is durable and it allows you can scan in contact mode, offering you faster calibration and measurements. This is the only high resolution 2D calibration specimen we have seen that offers the following characteristics:

• 2-dimensional array for simultaneous calibration of X and Y axes.
• Pitch <500 nm.
• Array of pumps mean the image contrast is high even when the probe tip is slightly dull.
• High contrast in contact mode scans.
• The pattern covers the entire die so that you don’t have to hunt for the scan area.

Ordering:

Model 150-2D is available either mounted on a steel disc or unmounted for AFM or Mounted or Unmounted for SEM.

80125-2D-UM	High Resolution Calibration Specimen, Model 150-2D, Unmounted for AFM	1077.00
80125-2D-M *	High Resolution Calibration Specimen, Model 150-2D, Mounted for AFM	1077.00
80125-2D-MS *	High Resolution Calibration Specimen, Model 150-2D, Mounted for SEM	1077.00
80126-2D-UM	High Resolution Calibration Specimen, Model 150-2DUTC, Unmounted for AFM	5777.00
80126-2D-M *	High Resolution Calibration Specimen, Model 150-2DUTC, Mounted for AFM	5777.00
80126-2D-MS *	High Resolution Calibration Specimen, Model 150-2DUTC, Mounted for SEM*	5777.00

X-Checker™

The X-Checker was the first and remains the only complete calibration aid for SEM/EDS Systems. When time is short but you want to know how well your system is performing you need the X-Checker. Each X-Checker comes with the following:

• Manganese to measure full width at half max detector resolution
• Aluminum and copper to perform spectral calibration.
• Carbon to monitor calibration at the low end of the spectra for thin window detectors.

You also get two grid sizes for checking the accuracy of your image analysis software and an easy test for monitoring the amount of vacuum pump oil contamination on your detector window.

• The X-Checker™ BN comes with boron nitride for those who need a more sensitive monitor of low end performance on thin window and windowless detectors.

• The X-Checker™ Extra is the ultimate performance monitor for the latest state of the art X-ray detectors. In addition to the standard features and boron nitride, there is a fluorine source to test resolution at the fluorine K-alpha peak (industry standard for measuring low end resolution). As well it comes with a beryllium grid for the ultimate test of detector performance.

80058-ST	X-Checker™, Standard	each	300.00
80058-BN	X-Checker™, With Boron	each	400.00
80058-EX	X-Checker™, Extra	each	400.00