SPM Calibration Specimens

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 (100 nm) polymer layer containing the pattern and a thin tungsten film over-coating the entire surface. The tungsten film varies from 20 nm to 60 nm in thickness, depending on the particular model. This structure has been proven under a wide variety of beam conditions, from 30kV to sub 12 kV.

Dimensions:
300 nm or 700 nm 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/brightness, 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 straightforward. 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 degrade 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 0.5 mm.

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. Especially 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 stigmation are obtained, the image can be shifted to an appropriate area and the desired measurements made.

2. 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 702CE standard 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 stigmation 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 discernible. 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 an EMS 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 an EMS 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 misadjusted 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	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	3 mm x 4 mm x 0.5 mm	3 mm x 4 mm x 0.5 mm	3 mm x 4 mm x 0.5 mm
Accuracy	± 3%	± 3%	± 1%
Nominal Dimensions	(x)	(x, y)	(x)
	300 nm for 301CE	700 nm for 702CE	300 nm for 301BE
	700 nm for 701CE
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 traceability is also available with an additional cost.

Applic.	Product	Pattern	Material	Nominal Pitch	Mounting	Cat. #	Price	Cart
SEM	701CE	Parallel Ridges	W-coated Photoresist on Si	700 nm	unmounted	80110-71	375.00	Add to Cart
					mounted	80110-71M	511.00	Add to Cart
SEM	301CE	Parallel Ridges	W-coated Photoresist on Si	300 nm	unmounted	80110-31	498.00	Add to Cart
					mounted	80110-31M	634.00	Add to Cart
SEM	702CE	Array of Posts	W-coated Photoresist on Si	700 nm	unmounted	80110-72	750.00	Add to Cart
					mounted	80110-72M	886.00	Add to Cart
AFM, SEM, TOF-SIMS, Auger, etc.	301BE	Parallel Ridges	Ti lines on silica	300 nm	unmounted	80111-31	1,364.00	Add to Cart
					mounted	80111-31M	1,500.00	Add to Cart

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

SS-301	301BE Certification	each	3,035.00	Add to Cart
SS-SEM	Mount Certified Specimen for SEM*	each	243.00	Add to Cart

* Silver epoxy is the default adhesive.

SPM Calibration Specimens

Overall Benefits:

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

Features and Benefits:

• Holographic fabrication - assures high accuracy and precision.
• Pattern height > 100 nm - 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 700 nm)
  -cylindrical posts (2-D 300 nm)
  -diamond-shaped posts (2-D 700 nm)
• Physical Size: 3 mm x 4 mm x 0.5 mm.
• 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.

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 150 nm, 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 AFM, 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.

Models 300-2D, 300-1D, 700-2D and 700-1D

All mounted on 15 mm steel disk.

Models 300-1D and 300-2D
	300-1D Parallel Ridges Pitch 288 W-coated Photoresist on Si use contact or TappingMode	300-2D Array of Posts Pitch 297 Al bumps on Si use contact or TappingMode
Models 700-1D and 700-2D
	700-1D Parallel Ridges Pitch 700 W-coated Photoresist on Si use contact or TappingMode	700-2D Array of Posts Pitch 700 W-coated Photoresist on Si use TappingMode

Model 302-EDU

Student grade calibration specimen. 2-dimensional, 297 nm nominal period. Aluminum bumps on Si.

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. Pereria, D.E.D, Chernoff, D., Claudio-da-Silva, Jr. E., & Cemuner, B.J., “The use of AFM to investigate the delignification process: Part I –AFM performance by differentiating pulping processes”, to be published.

150-1D	80125-1D	Unmounted	750.00	Add to Cart
	80125-1D-AFM	AFM	871.00	Add to Cart
	80125-1D-Pin	SEM pin	871.00	Add to Cart
	80125-1D-X	Choose mount	886.00	Add to Cart
300-1D	80123-1D	Unmounted	562.00	Add to Cart
300-1D	80123-1D-Pin	SEM pin	698.00	Add to Cart
	80123-1D-AFM	AFM	698.00	Add to Cart
	80123-1D-X	Choose the mount	698.00	Add to Cart
300-2D	80123-2D	Unmounted	960.00	Add to Cart
	80123-2D-Pin	SEM pin	1,016.00	Add to Cart
	80123-2D-AFM	AFM	1,286.00	Add to Cart
	80123-2D-X	Choose the mount	1,286.00	Add to Cart
301BE	80111-31	Unmounted	1,364.00	Add to Cart
	80111-31-Pin	SEM pin	1,473.00	Add to Cart
301CE	80110-31	Unmounted	498.00	Add to Cart
	80110-31-Pin	SEM pin	624.00	Add to Cart
302-EDU	80124-EDU	Unmounted	441.00	Add to Cart
	80124-EDU-Pin	SEM pin	567.00	Add to Cart
700-1D	80122-1D	Unmounted	439.00	Add to Cart
	80122-1D-AFM	AFM	439.00	Add to Cart
700-2D	80122-2D	Unmounted	879.00	Add to Cart
	80122-2D-AFM	AFM	879.00	Add to Cart
701CE	80110-71	Unmounted	375.00	Add to Cart
	80110-71-Pin	SEM pin	511.00	Add to Cart
702CE	80110-72	Unmounted	750.00	Add to Cart
	80110-72-Pin	SEM pin	886.00	Add to Cart
750-HD	80124-HD Unmounted	Unmounted	341.00	Add to Cart
PT	80124-PT		202.00	Add to Cart

 

Model 150-2D

Very High Resolution Reference and Traceable Standards for Magnification Calibration of 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, 4 x 3 mm die. Bump height (about 90 nm) and width (about 75 nm) are not calibrated.

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 non-traceable, 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 for Calibrator only:

Available in the following ways: unmounted, 15 mm steel disk(for AFM), SEM pin stub, or any other type of SEM stub.

Ordering for Calibrator only

150-2D	80125-2D	Unmounted	1,295.00	Add to Cart
	80125-2D-Pin	SEM Pin	1,406.00	Add to Cart
	80125-2D-AFM	AFM	1,295.00	Add to Cart
	80125-2D-X	Choose mount	1,355.00	Add to Cart
150-2DUTC	80126-2D	Unmounted	7,432.00	Add to Cart
	80126-2D-Pin	SEM Pin	7,167.00	Add to Cart
	80126-2D-AFM	AFM	7,432.00	Add to Cart
	80126-2D-X	Choose mount	7,167.00	Add to Cart

Very High Resolution Calibration Reference and Traceable Standard for AFM, SEM, Auger, and FIB

For General Purpose and Metrology Microscopes

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

Period: 70 nm pitch, one-dimensional array. Accurate to +/- 0.25 nm.  Refer to calibration certificate for actual pitch.

Surface: Silicon Oxide ridges on Silicon, 4 x 3 mm die.  Ridge height (about 35 nm) and width (about 35 nm) are not calibrated.

For AFM, use in contact, intermittent contact (TappingMode™) and other modes with image sizes from 100 to 3000 nm. Available unmounted or mounted on steel disks.

For SEM, this specimen works well at a wide range of accelerating voltages (1 kV to 20 kV have been tested) and calibrates images from 25 kX to 1000 kX. Normally supplied unmounted. Can be mounted on a stub of your choice.

Usability: The calibrated pattern covers a 1.2 x 0.5 mm area. There is sufficient usable area to make thousands of measurements without reusing any areas altered or contaminated by previous scans.

Model 70-1D

This Calibration Reference specimen comes with a non-traceable, manufacturer’s certificate. This states the average period, based on batch measurements. This specimen is available only mounted on steel disk.

Model 70-1DUTC

This Traceable, Certified Standard is measured in comparison with a standard calibrated at PTB. (PTB, Physikalisch-Technischen Bundesanstalt, is the German counterpart of NIST. The standard is “NIST-Traceable” by virtue of the mutual recognition agreement between NIST and PTB.) The uncertainty of single pitch values is typically +/- 0.5 nm (95% confidence interval). Multi-pitch measurements provide the usual square-root of N improvement in precision.

AFM Tapping Mode scan

The ridge height is about 35 nm. This specimen is not recommended as a height reference because the standard AFM probes may not always reach the substrate level between the ridges. Nevertheless, the image contrast is high, even when the probe tip is slightly dull. You can scan in contact mode, which means you can calibrate and measure faster.

Easy to find Patterned area

The patterned area is easy to find. The three rectangles shown in the sketch below are visible in reflected light, with either the unaided eye or an optical microscope. In a low magnification SEM image, the contrast is reversed. The central rectangle, which is the grating pattern, is relatively bright. The grating lines are parallel to the long side of the rectangle, as suggested by the high magnification SEM image.

Die and location of pattern within die:	Low magnification SEM image:

SEM High Magnification Image
Magnification= 200 kX
Voltage= 5 kV.

Ordering for the Very High Calibration and Traceable Standard:

Available in the following ways: unmounted, 15 mm steel disk(for AFM), SEM pin stub, or any other type of SEM stub.

80127-1DC	Calibration Standard Model 70-1D with Cert Unmounted	each	4,883.00	Add to Cart
80127-1DC-PIN	Calibration Standard Model 70-1D with Cert Mounted on Pin Stub	each	4,281.00	Add to Cart
80127-1D-AFM	Calibration Standard Model 70-1D with Cert Mounted on 15 mm Steel Disk for AFM	each	1,661.00	Add to Cart
80127-1DC-AFM	Calibration Standard Model 70-1D with Cert Mounted on Steel Disk for AFM	each	4,281.00	Add to Cart
80127-1DC-X	Calibration Standard Model 70-1D with Cert – Choose Mount	each	4,981.00	Add to Cart