D.I.Mendeleev Institute for Metrology

Scientific-research laboratory of Angle and Nanometrology
Scientific Center of Nanometrology

Members of group
Main directions of group`s work
Working instrument
Publications list
Calibrated measures
Postal address

Members of group:

Main directoions of group`s work:

1. Metrological maintenance of instruments of measurements - certification, calibration and certification of scanning probe microscopes, electronic microscopes and optical microscopes.

2. Manufacturing of calibrated small length measures for certification and calibration of scanning probe microscopes, electronic microscopes and optical microscopes.

Working instrument:

1. Metrological scanning probe microscope on the base of industrial SPM-SMENA-M / manufactured "NT-MDT" (Zelenograd). http://www.ntmdt.ru.

2. Laser microinterferometer for measurement and certification of measures of height of a step in a range from 7nm up to 1000nm with standard uncertainty from 0.7nm up to 2nm

3. Laser interference difractometer for measurement and certification of periodic measures in a range from 250nm up to 1000nm with standard uncertainty from 0.05nm up to 2nm

4. A digital optical microscope for measurement and certifications of measures of width of a line in a range from 1mcm up to 10mcm with standard uncertainty from 0.1mcm

Calibrated measures.

The Scientific Center of Nanometrology of VNIIM ( Russia, D.I. Institute for Metrology) developed the set of Small Length Standards:

1. Periodical Standards –1D Gratings (PS-300 – nominal 300 nm, standard uncertainty- 0.2 nm; PS-500 – nominal 500 nm, standard uncertainty – 0.3 nm; PS-700 – nominal 700 nm, standard uncertainty 0.5 nm).
2. Step Height Standards SHS-8,20,70,300,700 (nominals 8,20,70,300,700 nm; standard uncertainty 1.0,1.0,1.2,1.5,2.0 nm).
3. Line Width Standards LWS (from 1 mcm to 10 mcm with standard uncertainty 0.02-0.03 mcm). Small Length Standards provide the calibration value for measuring instruments in submicrometer- and nanometer range working in nanotechnology, microelectronics industry and science.

The Smal Length Standards satisfy to the general requirements developed for nanometrology standards developed by WGDM-7 (Working Group of Dimension Metrology, BIPM): the standards should meet requirements of different measuring methods, including optical, electron and probe microscopy. Traceability of calibration and certification are confirmed by CCL Preliminary Key Comparison (NANO-4 for PS-periodical standards, Nano-2 for SHS-step height standards).

1. Periodical standards - 1D-Gratings

General information

The periodical standards- holographic gratings provide the calibration value of the period (pitch) on the center 5x5 mm of the sample area. The accuracy (standard uncertainty) for pitch 300 nm is 0.2 nm, for pitch 500 nm – 0.3 nm, 700 nm – 0.5 nm. It is intended for XY-calibration and nonlinearity measurements for Scanning Probe Microscope (Atomic Force Microscope, Scanning Tunnel Microscope), Scanning Electron Microscope and etc. The grating PS-300 and PS-500 are VNIIM traceable. A supplementary specifications sheet detailing the exact values of the period (pitch) is attached to each samples.

1.1 Description of the standard.

The periodical standard - holographic grating with size 5 x 5 mm is placed on the quartz base with dimensions 12 x 12 x 3 mm. The coating are Aluminum or Gold. The standard has alignment scales.

1.2 Calibration and Certification of PS-gratings

Each PS-grating is individually controlled and certified. The measurements of the average pitch (spacing) were carried out by the interference diffractometry method. (see : V.I.Korotkov,S.A.Pulkin,A.L.Vitushkin,L.F.Vitushkin Appl.Optics,1996,vol.36,No 24,pp.4782-4786 ). The spacing (average pitch) ( P ) is evaluated from the ratio of the measured periods ( p0/p1 ) of the interference fringes defined by the angles between the beams diffracted from the reference grating (line scale) and from the grating to be measured. The setup – laser interference diffractometer (LID) has been used for the measurements. The optical scheme of LID is the optical scheme of the Michelson interferometer with optical system for obtaining the interference pattern on the CCD – camera . The reference line scale and investigating grating were placed to the arms of the interferometer . The alternative absolute 3-wavelength method (without reference line scale) was used too. The coincidence of the results between these two methods was some additional criterion for correctness of the measurements. Software permits to make statistical treatment of large volume of information by using spatial averaging pixels rows and by accumulating of few tens of frames. The uncertainty of measurements has been estimated according to ISO Guide to the Expression of Uncertainty in Measurement . The measurement and calibration technique is based on ISO-5436.

1.3 The quality of the standard.

The quality of the standard is individually controlled using Atomic Force Microscope. The roughness is measured and amplitude and standard uncertainty are estimated. The amplitude of roughness for typical grating is about 2 nm and standard uncertainty is about 0.7 nm.

2. Step-Height standard

General Information

The Step Height Standards provide the calibration value of the step height . The accuracy (standard uncertainty) for step height 8 nm is 1.0 nm , 20 nm is 1.0 nm, 70 nm – 1.2 nm, 300 nm – 1.5 nm, 700 nm-2.0 nm. It is intended for Z-calibration and nonlinearity measurements for Scanning Probe Microscope (Atomic Force Microscope, Scanning Tunnel Microscope), Scanning Electron Microscope and etc. The Step heights Standards PS-8, PS-20, PS-70 and PS-700 are VNIIM traceable. A supplementary specifications sheet detailing the exact values of the period (pitch) is attached to each samples.

2.1 Description of the standards

The standards consist of a 5 mm x 5 mm x 0.5 mm silicon chip. The measure is made in two variants of execution: variant 1-the measure(standard) represents the silicon chip in the sizes 5 х 5 х 0.5 mm. variant 2-the measure is made on a quartz substrate 12х 12х 4mm. (the sizes of a substrate can be changed). The surface of these standards is made conductive and opaque by a Chromium layer approximately 80 nm in thickness. There are three lines on the standards. The widths are 5 mcm, 30 mcm and 50 mcm. For the use of scanning probe microscopes, microinterferometer and heterodine interferometer we used the right line with a width of 30 mcm.

2.2 Description of the measurement methods and instruments

The height of the step height standards was determined by the laser Michelson microinterferometer, which was illuminated by the plane waves of light of the Ar or He-Ne lasers. The sample (standard) was placed in the first arm of the interferometer and was oriented perpendicular to the laser beam. The mirror was placed in the second arm. All measurements were carried out with the mirror tilted slightly with respect to the optical axis, thus were produced several (15-20 fringes) interference fringes in field of view(on 100 mcm). The tilt direction was such that the fringes crossed of the rectangular step. The interference pattern was passed by two objectives at the microscope focal plane. The spatial filtration in focal plane of the first objective allowed to make a selection of pair of the beams. After the microscope the phase interference image of the step was recorded by a 736x572 pixel CCD camera. The computer analysed the phase of the light for each pixel and calculated the average step height and type A standard uncertainty. On each standard measurement cycles more suitable from the five different wavelengths were performed. The laser vacuum wavelengths and the wavelength uncertainties given in “Handbook of lasers with selected date on optical technology”(Edited by R.J.Pressiey. Chemical Rubber Co, Cleveland, 1971). The software permits to statistical treatment of large volume of information by averaging on many rows of pixel and by accumulating of few tens of frames. The most important type B standard uncertainty sources is incident angle uncertainty. The set of measurements for each sample were made for elimination of defocusing and diffraction effects uncertainties. Set uncertainty was included to standard uncertainty as uncertainty of Type B. The measurements were made on the reference temperature of 20 with standard uncertainty u(t)=0.5

2.3. Quality of Step height standards

Step edge quality

The Quality of step edge there was explored on atomic -force microscope (AFM) SFOM. The quality of the edge was estimated on maximum deflections from line ?b1 and ?b2. The estimation is produced in workspace of measure (under greatly possible area of scan –101mcm). The results of estimations on all standards are included in the table 2.1.

Table 2.1

1	SHS-8	db1=0.2mcm	db2=0.6mcm
2	SHS-20	db1=0.2mcm	db2<0.1mcm
3	SHS-80	db1=0.6mcm	db2<0.1mcm
4	SHS-300	db1=0.6mcm	db2=0.8mcm
5	SHS-700	db1=0.6mcm	db2=0.6mcm

2.4. Roughness of SHS

The estimation of surface roughness was conducted in workspace of standards inwardly and outside of the steps. The results of roughness estimations on all standards are shown in the Table 2.2.

Table 2.2

nominal value	8нм (SHS-8)	20нм (SHS-20)	80нм (SHS-80)	300нм (SHS-300)	700нм (SHS-700)
in the step	1,99nm	2,16nm	1,56nm	1,91nm	1,75nm
out of step	2,83nm	2,45nm	1,17nm	1,65nm	1,79nm

3. Line width Standards (LWS)

General Information

The Step Height Standards provide the calibration value of the step height . The accuracy (standard uncertainty) for line width 1.0 mcm is 1mcm, for 2 mcm and above-0.03 mcm. It is intended for width-calibration Optical Microscope,for Scanning Probe Microscope (Atomic Force Microscope, Scanning Tunnel Microscope), Scanning Electron Microscope and etc. A supplementary specifications sheet detailing the exact values of the line width is attached to each samples. Line width standards provide the calibration value of the line width.

3.1. Description of the standard.

The Line Width Standard is made from chromium photoplate by conventional photolithographic technique.

3.2 Calibration and Certification of Line Width Standards

Each sample of LWS is individually controlled and certified. The line width is measured using Optical Digital Microscope and Calibrated Atomic Force microscope.

3.3 Quality of the Line Width Standards

The quality of edge and surfaces are determined using Atomic Force Microscope. The standard uncertainty for edge is about 1 mcm and roughness is about 1-2nm (standard uncertainty).


The Scientific Center of Nanometrology of VNIIM D.I.Mendeleeva offers:

1. Services in metrological maintenance, certification, calibration and certification Scanning probe microscopes, Electronic microscopes and optical microscopes.
2. The complete set of the certificated measures of small length for calibration of Scanning probe microscopes, Electronic microscopes and optical microscopes

Contact person:

Korolev Alexander Nikolaevich, chief of laboratory

Postal address:

D.I.Mendeleev institute for metrology

19, Moscovskii pr. , Saint- Petersburg, Russia, 198005

Tel.: ++7 (812) 251-86-38

E-mail: a.n.korolev@vniim.ru