CN1255669C - Scanning electronic microscope standard substance and its making method - Google Patents

Abstract

The invention relates to a standard substance used for calibrating the magnification of a scanning electron microscope and a preparation method thereof. Its substrate is coated with a measuring film, and the measuring film is coated with a conductive layer. The measuring film is an array of monodisperse polystyrene standard particles closely arranged in hexagons, and a substrate is placed on the sample holder. a. Select the aqueous solution of monodisperse polystyrene standard particles and select the substrate; b. Clean the substrate; c. Sprinkle the aqueous solution of monodisperse polystyrene standard particles on the substrate; ° put into the clean room and dry naturally; e. the substrate is embedded in the sample holder; f. the aqueous solution of monodisperse polystyrene standard particles adsorbed on the substrate and dried is coated with a conductive layer with an ion sputtering instrument, and the conductive layer is It is a gold layer, the purity of the gold layer is at least 99%, and the thickness of the gold layer is 5nm-20nm. The invention expands the calibration range of the scanning electron microscope, and can provide the traceability value within the calibration range and the uncertainty of a given confidence interval.

Description

A scanning electron microscope standard substance and its preparation method

technical field

The invention relates to the technical field of measurement and test standard value transfer, in particular to a standard substance (standard sample) for calibrating the magnification of a scanning electron microscope and a manufacturing method thereof.

Background technique

Today, as human society enters the 21st century, with the rapid development of nanotechnology worldwide, nanotechnology has been widely used in laboratory basic scientific research, data collection for product development and quality control in the production process. Now many quality assurance systems, such as the ISO9000 series, require that the data obtained should have traceability values. At the same time, the resolution of the scanning electron microscope, which is an important means of observing nanostructures, is getting higher and higher, which requires that the image data at higher and higher magnifications also have traceable values. However, the current commercially available standard material calibration range for scanning electron microscopy is limited to less than 20,000 times. For example, the certified reference material SRM484g of the National Institute of Standards and Technology (NIST) of the United States (the range of use specified in the calibration document is 1000 times to 20000 times); It is traceable and calibrated by the National Institute of Physics (NPL). For the 2160 line/mm square grating certified standard material of the British Agar Scientific Company, the calibration value of the British National Institute of Physics is that the uncertainty of every 10 grids is ±0.05 μm, that is, the spacing of the standard material is 4.6 μm The uncertainty is ±0.05μm. When the magnification exceeds 20,000 times, the final imaging pitch of 4.6 μm pitch is greater than 9 cm, which has exceeded the format (ie scanning range) of the final imaging photo of a general scanning electron microscope, and the image of this magnification cannot be calibrated, so it cannot adapt to the current Scanning electron microscopes require increasingly higher resolutions. For example, the resolution of a general field emission gun electron microscope is about 1.0-1.5nm. In order to adapt to the development of nanotechnology in the current scientific and technological field and effectively play the role of high-resolution scanning electron microscopes, it will become more and more common laboratory work to use 100,000 to 200,000 times magnification to take images and photographs. (1nm is 0.2mm on a magnified photo of 200,000 times, while the point resolution of the human eye is 0.2mm) In order to meet the needs of scanning electron microscope high magnification calibration, the present invention has developed a 1000 times to 200000 times calibration Standard substance (standard sample).

Contents of the invention

The technical problem to be solved by the present invention is to provide a calibration magnification of 1000 times to 200000 times, and can give the traceability value within the range of calibration magnification, and attach the uncertainty of a given confidence interval, so that The calibrated high-magnification image data has a scanning electron microscope standard substance (standard sample) with traceable value and its preparation method. The technical scheme adopted by the present invention to solve the technical problem is: a scanning electron microscope standard substance, its substrate is coated with a measuring film, the measuring film is coated with a conductive layer, and the measuring film is monodisperse polystyrene with hexagonal closely arranged A standard particle array, the standard particle array is formed by a dried monodisperse polystyrene standard particle aqueous solution, and a substrate is placed on the sample holder. A method for making a scanning electron microscope standard substance, comprising the following steps: a. selecting an aqueous solution of monodisperse-phase polystyrene standard particles, and selecting a substrate; b. cleaning the substrate; c. dropping the aqueous solution of monodisperse-phase polystyrene standard particles Sprinkle on the substrate; d. Put the substrate and the horizontal plane at 0°～5° into a clean room to dry naturally; e. Embed the substrate in the sample holder; f. Use an ion sputtering device to absorb and dry the monodisperse phase The polystyrene standard particle aqueous solution is plated with a conductive layer, the conductive layer is a gold layer, the purity of the gold layer is at least 99%, and the thickness of the gold layer is 5nm-20nm. . The aqueous solution of monodisperse polystyrene standard particles is selected from the products of Duke Science Company of the United States. The task proposed by the present invention can be further realized through the following technical solutions: a substrate is placed on the sample holder; the substrate is a glass plate with a surface roughness less than 20nm, a thickness of 1mm-1.5mm, and a diameter of 5mm-10mm; The physical and chemical parameters of the monodisperse phase polystyrene standard particle aqueous solution are solid content (content of polystyrene standard particle in aqueous solution) 0.2% to 2%, density 1.05g/cm ³ , refractive index 1.59@589nm/23 ℃, the diameter of the monodisperse polystyrene standard particle is 0.2 μm to 10 μm, the relative standard deviation of the monodisperse polystyrene standard particle diameter is 0.5% to 2%, and the usage amount V of the monodisperse polystyrene standard particle aqueous solution is given by Determined by the following formula: V=CSd/p, where C is 0.3 to 1.0, S is the surface area of the substrate, d is the diameter of the standard particle in the aqueous solution of monodisperse polystyrene standard particles, and p is the monodisperse polystyrene standard The solid content of the particle aqueous solution; the cleaning is to immerse the substrate in 100% ethanol and clean it with an ultrasonic cleaner for 5 to 15 minutes; the room temperature of the clean room is 18°C to 22°C; the humidity is 60% ±5%; the substrate is embedded in the sample holder; a conductive layer is plated on the aqueous solution of monodisperse polystyrene standard particles adsorbed on the substrate and dried; the conductive layer is a gold layer, and the purity of the gold layer is at least 99%. The thickness of the layer is 5nm-20nm, and the dried monodisperse polystyrene standard particle aqueous solution is plated with gold by using an ion sputtering device. Due to the adoption of the above technical scheme, the present invention expands the calibration range of the scanning electron microscope (1000 times to 200000 times), and can provide traceability values within the calibration range, and attach the uncertainty of a given confidence interval, so that scanning Electron microscopes meet the requirements of the ISO9000 quality assurance system when used within the calibrated range.

Description of drawings

The present invention will be described in further detail below in conjunction with accompanying drawing and specific embodiment of the present invention:

Fig. 1 is a schematic diagram of the structure of the present invention.

Fig. 2 is an enlarged view of part A of Fig. 1 (an array view of monodisperse polystyrene standard particles after drying).

Figure 3 is a 200,000-fold magnified view of a 0.3 μm standard particle.

FIG. 4 is a 2,000-fold magnified view of a 1.0 μm standard particle.

Refer to Figure 1 and Figure 2. The invention comprises a substrate 2, a measuring film 4, a conductive layer 1 is plated on the measuring film 4, and a substrate 2 is placed on a sample holder 3.

Detailed ways

Embodiment 1: With reference to Fig. 1, Fig. 2. The measurement film (dried monodisperse polystyrene standard particle aqueous solution) is coated on the substrate of the present invention, and then gold is plated on the measurement film to perform magnification calibration.

Embodiment 2: With reference to Fig. 1, Fig. 2. For the convenience of calibration, the same technical effect as in Example 1 can also be achieved by placing the plated measurement film and the gold-plated substrate on the sample holder.

Embodiment 3: with reference to Fig. 1, Fig. 2. Firstly, the physical and chemical parameters provided by Duke Scientific Corporation of the United States are 1%, the density is 1.05g/cm ³ , and the particle size is 0.3μm monodisperse polystyrene standard particle aqueous solution (monodisperse phase) with a refractive index of 1.59@589nm/23℃. The relative standard deviation of the polystyrene standard particle diameter is 1.4%), the surface roughness (Ra) is less than 20nm, the thickness is 1mm, and the glass plate that the diameter is 10mm is used as the substrate; then the substrate is immersed in 100% ethanol, and the The washing machine cleans the substrate for 8 minutes; then the monodisperse polystyrene standard particle aqueous solution is dripped on the substrate (the usage amount V of the monodisperse polystyrene standard particle aqueous solution should satisfy the following formula: V=0.6Sd/p ), so that it forms a spherical array of standard particles in a single layer and hexagonal close arrangement. The arrangement principle of the standard particle spherical array is: with the volatilization of water, when the water becomes less and less, the gradually increasing capillary force makes the particles of the monodisperse polystyrene standard particle aqueous solution gather together. Sheets of monolayer particles finally form a densely packed array. A very small amount of large particles are extruded into the array, so that the statistical standard deviation of the arrayed particles will be better than the original solution. Then put the substrate and the horizontal at 0°~5° into a clean room with a room temperature of 18°C~22°C and a humidity of 60%±5% to dry naturally, and after drying, insert the substrate into the sample holder At this time, the thin film formed by the monodisperse phase polystyrene standard particles can be observed with the naked eye under sunlight, and the spectral effect similar to that of a diffraction grating can be observed.) Finally, ion sputtering is used on the dried monodisperse phase polystyrene standard particles. A gold-plated layer, the thickness of the gold layer is 8nm.

The present invention adopts the certified standard spherical particles provided by Duke Science Corporation of the United States to develop standard materials including 0.2 μm; 0.3 μm; 0.5 μm; 1 μm arranged spherical particles, which are used to calibrate the magnification of the scanning electron microscope at 1000 times to 200000 times. The monodisperse polystyrene standard particle aqueous solution is an aqueous suspension whose average particle size is traceable to the length measurement standard of the American Institute of Standards and Technology. Its density is 1.05g/cm ³ , and its refractive index is 1.59@589nm (23°C). Its other technical parameters are shown in Table 1 (attached).

In the present invention, the above four kinds of standard particles are made into large-area single-layer hexagonal closely arranged standard substances. Since the boundary of dispersed particles has a certain gray level, it cannot be well determined, which will bring a large error to the measurement. In addition, if the dispersed particles are wrapped by the gold-plated layer, their real boundaries are more difficult to determine. Therefore, the present invention adopts the method of closely arranging the standard particles instead of dispersing the standard particles uniformly. Photo 1 and Photo 2 are 200,000 times magnified diagrams of 300nm standard particles and 2,000 times magnified diagrams of 1.0 μm standard particles made by the present invention. From Photo 1, the present invention can see that when the magnification of the scanning electron microscope reaches 200,000 times, the 0.3 μm standard particle is 6 cm, and the magnification can still be effectively calibrated. For the calibration of different magnifications, the present invention suggests using standard particles of different particle sizes: 0.2 μm (20,000 times to 300,000 times); 0.3 μm (10,000 times to 200,000 times); 0.5 μm (5,000 times to 50,000 times); 1.0 μm (1,000 times to 10,000 times).

The present invention needs to calibrate the present invention before the measurement standard value transmission, and the calibration method example of the present invention is as follows: The present invention adopts the XL/ESEM30 scanning electron microscope of Netherlands Philips company to the certified standard substance of 2160 line/mm of British Agar scientific company (The calibration value of the British National Institute of Physics is 4.6 μm ± 0.05 μm/10 divisions) and the standard material of the tight arrangement particles of the present invention are compared with other conditions. The working conditions of the scanning electron microscope selected in the present invention are: 15kV/accelerating voltage; 2.4/beam spot size; 20,000 times/magnification; secondary electrons/detector; 10.0/working distance. Under this working condition, photographs were taken at 5 different parts of the British Agar standard sample, and each photograph was measured up, middle and down three times in the horizontal direction. The data read are shown in Table 2 (attached). Photographs were taken of the closely arranged particle samples of the present invention under certain conditions, 9 different samples were selected, and 6 arrangement blocks were selected for each sample, and each arrangement was measured 3 times with 10 particles in a row. The read data is shown in Table 3 (Attached).

Data processing and uncertainty evaluation of the present invention:

a) The certified reference material (SRM) that the present invention is used for relative calibration is the standard material of 2160 lines/mm of Agar scientific company, and it is calibrated by the British National Institute of Physics with a scanning electron microscope plus a laser interferometer, and its calibration value is : 4.6μm±0.05μm/10 divisions. Its relative uncertainty Da=0.05/4.6=1.1%.

b) Due to the different working distances of scanning electron microscopes, the nominal value and actual value of the same magnification will have slight changes. The adjustment accuracy of the working distance of Philips XL/ESEM30 scanning electron microscope is 0.1mm, and it is 9.950～10.049 at 10mm. The data of the magnification change with the working distance is shown in Table 4 (attached).

Set the working distance as X, the average value measured by the same interval length of the certified reference material with the same magnification as Y, and use the data in Table 4 to fit the linear regression curve with the least squares method.

                                                  

Where: m=0.0136; b=4.596

Formula 1 becomes: Y=0.0136X+4.596

  ΔY＝0.0136ΔX

The 0.1 generation ΔX gets ΔY=0.00136

    ΔY/Y＝0.00136/4.737≈0.0003＝0.03%

Among them, Y=4.737 is the measured average value when the working distance is 10mm.

Therefore, when the maximum working distance is 10mm, the uncertainty Db of the magnification caused by the uncertainty of 0.1mm is about 0.03%.

c) If the measurement line is not completely horizontal, there will be uncertainty due to the fact that the horizontal magnification of the scanning electron microscope is not completely consistent with the vertical magnification. The method of measuring the error between the horizontal magnification and vertical magnification of the XL/ESEM30 scanning electron microscope for calibration at 20,000 times magnification is as follows: First, in the same field of view where the Agar standard material is magnified 20,000 times, take The average of the three measurements was taken and the ratio was calculated. Here the ratio P of the vertical magnification to the horizontal magnification is calculated by formula 2.

P＝(3.81+3.82+3.82)/(3.81+3.79+3.80)＝1.004 Formula 2

In order to be consistent with the measurement state of comparing certified standard substances, the present invention adopts the rotation of the sample stage to keep the standard particle measurement level. However, judging from the measurement photos, the measurement lines are not completely horizontal, and the maximum deviation of their angles is less than 2°, so the uncertainty of the horizontal inclination of the image is 2°. The uncertainty Dc caused by the incomplete level of the image measurement line is expressed by Equation 3.

Dc＝1-[P ² ×sin ² α+cos ² α] ^1/2 Formula 3

Among them: P is the ratio of vertical magnification to horizontal magnification.

α is the maximum angle between the measurement line and the horizontal line of the image.

Substitute P=1.004, α=2° into Equation 3

Dc＝|1-[1.004 ² ×sin ² (2°)+cos ² (2°)] ^1/2 |≈0.000014＝0.0014％

Therefore, because the horizontal magnification of the scanning electron microscope is not completely consistent with the vertical magnification, the uncertainty caused by the incomplete horizontal measurement line can be ignored compared with the uncertainty caused by other reasons.

d) The uncertainty of the measured value of XL/ESEM30 scanning electron microscope computer image software for calibration is 0.01 μm at 20,000 times, so for the measurement of a group of 10, the uncertainty of each standard particle is Dd = 1nm ( 0.33%).

The final calibration values are:

Average value of standard particles: Mp=0.3015μm (see Table 3)

Type A uncertainty: ΔA = (10) ^1/2 × S (total standard deviation) = (10) ^1/2 ×

0.0016 = 0.0051 μm (1.68%)

Among them: S＝[∑(u _i -ū) ² /(n-1)] ^1/2 (u _i : every measured value/10; n＝161)

Type B uncertainty: ΔB=(Da ² +Db ² +Dd ² ) ^1/2 ≈1.14% (3.4nm)

Among them: Da, Db, Dd are linearly independent. The standard deviation S _sample =0.9nm of the average value of each sample measured value (seeing table 3)

From the results of data processing and uncertainty evaluation of standard particle samples, the average value of standard particles is 1.5nm (0.5%) larger than the original data given by Duke Science. This is mainly due to the fact that there are imperceptible gaps between each particle during the arrangement of the particles (after the gold (Au) layer is sputtered, it will be even more imperceptible.) and the impurity left over from the particle aggregation process. matter of existence. The main source of type B uncertainty exists in the traceability uncertainty brought by the certified reference material of Agar Science Company used for calibration, the image resolution of Philips XL/ESEM30 used for calibration, the computer software and display used for measurement The screen resolution is not high enough. The Type A uncertainty is also slightly larger than the standard deviation derived by Duke Scientific using TEM. The present invention thinks that the main reason is that the error of the measured value is large, and the arrangement of particles has the function of removing particularly large and particularly small particles, because these particles are not suitable for arrangement, and the result will be better than the monodispersity of the original particles . The results would be more satisfactory if calibrated using a field emission gun scanning electron microscope with a higher image resolution and computer software with a higher screen resolution. From the uniformity data of the samples (the standard deviation S sample of the mean value of the measured values of each sample), the present invention thinks that the data between the samples are quite consistent. Furthermore, when using this sample to calibrate the scanning electron microscope, the present invention proposes to choose as much as possible the aligned particles in bulk for measurement, so as not to introduce additional uncertainties. The above-mentioned calibration procedure is only an example of obtaining the traceability value in the present invention, if a laser interferometer plus a scanning electron microscope is used for calibration, better results will be obtained.

The comparison of the present invention with the technical parameters of the certified reference material SRM484g of the scanning electron microscope of the National Institute of Standards and Technology (NIST) is shown in Table 5 (attached). The certified standard material is a standard material made of a thin gold (Au) layer embedded in a 0.5μm, 1μm, 3μm, 5μm metal nickel (Ni) layer after section polishing. From the data in Table 2, when it uses "3→4" and "4→5", its uncertainty is 1% to 1.5%. When magnified 20,000 times, its calibration uncertainty will quickly become larger (7.8% ~ 3.8%) when using "0→1", "1→2", "2→3", so it is in the calibration file The specified range of use is 1,000 times - 20,000 times. It is calibrated using laser interferometry plus scanning electron microscopy, which is an absolute measurement method. In addition, the certified reference material of British Agar Scientific Company is the traditional 2,160 line/mm grid reference material. It was calibrated by the British National Physical Laboratory (NPL) using laser interferometry plus scanning electron microscopy. Its uncertainty is 4.6μm+0.05μm/10 divisions (1.1%). When it uses less than 10 divisions to calibrate the scanning electron microscope, there will be no traceable value, so it will also limit its use at high magnification.

The monodisperse phase polystyrene standard particle aqueous solution stock solution in the present invention comes from the certified reference material of Duke Science Company. Combining its own fixed value uncertainty, its composite total uncertainty is relatively large. For 3μm particles, it is about 3.4nm (1.14%), and the standard deviation is 5.1nm (1.68%). When measuring, the standard deviation can be reduced to ΔA/(n) by measuring the average value of multiple particles (n) ^1/2 ). The advantage of the present invention is that it can calibrate a large magnification (20,000 times to 200,000 times) under the condition of traceable value without making the calibration uncertainty change greatly, and from the surface of the standard substance, the particle The height difference between the apex and the junction is 1/2 of the particle diameter, (a particle with a diameter of 0.3 μm is 0.15 μm.) It is larger than other commercial scanning electron microscope standard substances, which gives users better viewing experience when using a scanning electron microscope. image contrast, which brings great convenience. sample number particle size Calibration average particle size Standard Deviation and Relative Standard Deviation solid content 3200A 200nm 199nm±6nm 3.4nm (1.7%) 1% 3300A 300nm 300nm±5nm 4.3nm (1.4%) 1% 3500A 500nm 499nm±5nm 6.5nm (1.3%) 1% 4009A 1000nm 993nm±21nm 10nm (1.0%) 1%

Table 1 Agar scientific company certified reference material measurement data (2160 lines/mm square grating) Acc.: 15.0; Spot: 2.4; Magn: 20000x; Det: SE; WD: 10.0 measurement 1 measurement 2 Measurement 3 average value photo 1 4.74 4.74 4.74 4.740 photo 2 4.74 4.74 4.74 4.740 photo 3 4.74 4.74 4.74 4.740 photo 4 4.74 4.74 4.74 4.740 photo 5 4.74 4.74 4.74 4.740 photo 6 4.74 4.75 4.74 4.743 total measurement average 4.741 Magnification factor: total measurement average / 4.6 = 1.031

Table 2 Closely arranged standard particles standard substance measurement data ACC.: 15.0kV; Spot: 2.4; Magn: 20000x; Det: SE; WD: 10.0 sample number photo number serial number measurement 1 measurement 2 Measurement 3 Measure mean particle size Sample mean 1 1 1 3.11 3.10 3.08 3.097 0.3097 1 1 2 3.10 3.11 3.10 3.103 0.3103 1 2 3 3.10 3.11 3.10 3.103 0.3103 1 3 4 3.11 3.13 3.10 3.113 0.3113 1 4 5 3.12 3.13 3.11 3.120 0.3120 1 4 6 3.09 3.10 3.11 3.100 0.3100 0.3106 2 5 7 3.11 3.12 3.10 3.110 0.3110 2 5 8 3.11 3.12 3.13 3.120 0.3120 2 6 9 3.11 3.10 3.11 3.107 0.3107 2 7 10 3.10 3.11 3.12 3.110 0.3110 2 7 11 3.08 3.08 3.07 3.077 0.3077 2 8 12 3.12 3.11 3.09 3.107 0.3107 0.3105 3 10 13 3.13 3.12 3.12 3.123 0.3123 3 10 14 3.12 3.12 3.13 3.123 0.3123 3 11 15 3.13 3.11 3.11 3.117 0.3117 3 11 16 3.11 3.08 3.12 3.103 0.3103 3 12 17 3.12 3.13 3.12 3.123 0.3123 3 12 18 3.11 3.13 3.13 3.123 0.3123 0.3119 4 14 19 3.13 3.13 3.09 3.117 0.3117 4 14 20 3.11 3.12 3.10 3.110 0.3110 4 15 twenty one 3.13 3.14 3.13 3.133 0.3133 4 15 twenty two 3.13 3.11 3.09 3.110 0.3110 4 16 twenty three 3.13 3.12 3.13 3.127 0.3127 4 16 twenty four 3.10 3.12 3.13 3.117 0.3117 0.3119 5 17 25 3.08 3.08 3.08 3.080 0.3080 5 17 26 3.08 3.11 3.09 3.093 0.3093 5 18 27 3.10 3.11 3.10 3.103 0.3103 5 19 28 3.11 3.07 3.08 3.087 0.3087 5 19 29 3.12 3.10 3.13 3.117 0.3117 5 20 30 3.07 3.06 3.06 3.063 0.3063 0.3091 6 twenty one 31 3.08 3.09 3.10 3.090 0.3090

Continued

take over 6 twenty one 32 3.09 3.09 3.090 0.3090 6 twenty two 33 3.13 3.11 3.10 3.113 0.3113 6 twenty two 34 3.11 3.11 3.11 3.110 0.3110 6 twenty three 35 3.13 3.10 3.10 3.110 0.3110 6 twenty three 36 3.10 3.09 3.09 3.093 0.3093 0.3101 7 twenty four 37 3.11 3.11 3.10 3.107 0.3107 7 twenty four 38 3.10 3.09 3.10 3.097 0.3097 7 25 39 3.12 3.11 3.12 3.117 0.3117 7 25 40 3.11 3.11 3.13 3.117 0.3117 7 26 41 3.11 3.10 3.11 3.107 0.3107 7 26 42 3.08 3.10 3.10 3.093 0.3093 0.3106 8 27 43 3.11 3.11 3.11 3.110 0.3110 8 27 44 3.12 3.11 3.13 3.120 0.3120 8 28 45 3.11 3.13 3.13 3.123 0.3123 8 28 46 3.12 3.11 3.09 3.107 0.3107 8 29 47 3.12 3.10 3.12 3.113 0.3113 8 29 48 3.09 3.09 3.10 3.093 0.3093 0.3111 9 30 49 3.10 3.11 3.12 3.110 0.3110 9 30 50 3.09 3.09 3.11 3.097 0.3097 9 31 51 3.10 3.09 3.09 3.093 0.3093 9 31 52 3.11 3.12 3.10 3.110 0.3110 9 32 53 3.12 3.13 3.12 3.123 0.3123 9 32 54 3.13 3.13 3.12 3.127 0.3127 0.3110 average value 3.11 3.11 3.11 0.3108 0.3108 standard deviation 0.0157 0.0168 0.0172 0.0014 0.0009 Overall mean M _p = 0.3108 Total standard deviation S = 0.0016 The standard deviation S _sample of the mean value of each sample measured value= 0.0009 Calibration value: particle size value/magnification factor=0.3108/1.031= 0.3015 ^* Particle size value=Measurement average value/particle number of each measurement particle.

table 3 The magnification varies with the working distance experimental data Acc.: 15.0kV; Spot: 2.4; Magn: 20000x; Det: SE Working distance(mm) measurement 1 measurement 2 Measurement 3 average value 6.0mm 4.67 4.67 4.68 4.673 7.0mm 4.69 4.69 4.68 4.687 8.0mm 4.71 4.70 4.72 4.710 9.0mm 4.72 4.74 4.72 4.727 10.0mm 4.73 4.74 4.74 4.737 11.0mm 4.74 4.74 4.75 4.743 12.0mm 4.76 4.77 4.75 4.760 13.0mm 4.77 4.75 4.75 4.757 14.0mm 4.78 4.79 4.79 4.787 15.0mm 4.81 4.80 4.81 4.807

Table 4 line pair Spacing value (μm) Calibration spacing value (μm) Uncertainty (μm) 0→1 0.5 ±0.034 1→2 0.5 ±0.039 2→3 1 ±0.038 3→4 3 ±0.044 4→5 5 ±0.051 0→5 (10) (±0.059)

table 5

Claims (6)

1. scanning electron microscope standard substance is characterized in that: be coated with the measurement film on its substrate, measure on the film and be coated with conductive layer, measuring film is the compact arranged single disperse phase polystyrene standard PArray of hexagonal, is equipped with substrate on the specimen holder.

2. the method for making of a scanning electron microscope standard substance is characterized in that: it comprises the steps,

A. choose single disperse phase polystyrene standard particle aqueous solution, choose substrate;

B. cleaning base plate;

C. the water-soluble drop of single disperse phase polystyrene standard particle is sprinkled upon on the substrate;

D. substrate is put into decontamination chamber's air dry horizontal by 0 °～5 °;

E. substrate embeds specimen holder;

F. dried single disperse phase polystyrene standard particle aqueous solution plates conductive layer on the substrate to being adsorbed on ion sputtering instrument, and described conductive layer is the gold layer, and the purity of gold layer is at least 99%, and the thickness of gold layer is 5nm～20nm.

3. the method for making of a kind of scanning electron microscope standard substance according to claim 2 is characterized in that: it is that 1mm～1.5mm, diameter are the glass plate of 5mm～10mm less than 20nm, thickness that described substrate is selected surfaceness for use.

4. the method for making of a kind of scanning electron microscope standard substance according to claim 2 is characterized in that: the physical and chemical parameter of described single disperse phase polystyrene standard particle aqueous solution is solids content 0.2%～2%, density 1.05g/cm ³, refractive index 1.59@589nm/23 ℃, single disperse phase polystyrene standard particle diameter is the relative standard deviation 0.5%～2% of 0.2 μ m～10 μ m, single disperse phase polystyrene standard particle diameter, the use amount V of single disperse phase polystyrene standard particle aqueous solution is determined by following formula: V=CSd/p, surface area, the d that C is 0.3～1.0 in the formula, S is substrate are that diameter, the p of standard particle in single disperse phase polystyrene standard particle aqueous solution is the solids content of single disperse phase polystyrene standard particle aqueous solution.

5. the method for making of a kind of scanning electron microscope standard substance according to claim 2 is characterized in that: described cleaning is that substrate is immersed in 100% the ethanol, and cleans 5～15 fens kinds with supersonic wave cleaning machine.

6. the method for making of a kind of scanning electron microscope standard substance according to claim 2 is characterized in that: the room temperature of described decontamination chamber is 18 ℃～22 ℃; Humidity is 60% ± 5%.

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