JP2024066035A - Sample observation stand and sample measurement device - Google Patents

Abstract

[Problem] To provide a sample observation stage capable of heating or cooling a sample while suppressing thermal expansion or thermal contraction of the sample stage in nano-measurement. [Solution] A sample observation stage 1 for nano-measurement capable of heating or cooling a sample 91 comprises a temperature adjustment element 11 for heating or cooling the sample 91, a sample stage 21 on which the sample 91 is placed, and a heat medium 31 having thermal conductivity and flexibility, sandwiched between the temperature adjustment element 11 and the sample stage 21. The heat conductivity of the heat medium 31 is higher than that of the sample stage 21. [Selected Figure] Figure 1

Description

This disclosure relates to a sample observation stage and a sample measurement device.

In a scanning probe microscope that measures the surface unevenness or surface properties of a sample, a technique has been disclosed in which the surface temperature measuring means is moved to a point where the temperature is to be measured by using a means for measuring the surface temperature of the sample and a means for moving the surface temperature measuring means (for example, Patent Document 1).

JP2003-222582A

In measuring nanometer-scale structures (hereinafter also referred to as "nano measurement"), there are cases where it is necessary to heat and cool a sample and measure its temperature dependence. In this case, the thermal expansion and contraction of the sample stage of the sample observation table becomes a problem. That is, when a sample is heated or cooled to measure the temperature dependence of the sample, the stage surface of the sample stage thermally expands or contracts. As a result, the distance between the measurement device and the sample fluctuates over time. Such fluctuations cause a decrease in measurement accuracy and reliability. In particular, if there is air or gas around the sample stage, the temperature of the heating surface is likely to fluctuate due to the flow of gas and thermal convection. This may cause the measurement surface (measurement position) to fluctuate to an extent that interferes with the measurement. Depending on the measurement environment, it may be difficult to block the flow of surrounding air and gas. Also, if gas is present, thermal convection cannot be avoided. If you try to suppress nanometer-scale fluctuations by controlling the heating and cooling elements, extremely high-precision control is required. Such precise control is actually difficult to achieve.

Furthermore, when measuring microscopic areas, uniform heating is required. However, the uniformity of heating depends on the adhesion between the sample and the sample stage. Therefore, to achieve accurate measurements, it is necessary to sufficiently increase the adhesion between the sample and the sample stage. If the sample stage thermally expands or contracts as described above, this adhesion will be impaired.

The present disclosure has been made in light of these circumstances, and its purpose is to provide a sample observation stage that can heat or cool a sample while suppressing thermal expansion or contraction of the sample stage in nano-measurement.

In order to solve the above problems, a sample observation stage according to one embodiment of the present disclosure is a sample observation stage for nano-measurement capable of heating or cooling a sample, and includes a temperature adjustment element for heating or cooling the sample, a sample stage on which the sample is placed, and a heat medium having thermal conductivity and flexibility that is sandwiched between the temperature adjustment element and the sample stage. The thermal conductivity of the heat medium is higher than that of the sample stage.

In one embodiment, the material constituting the heat transfer medium may include any of the following: liquid metal, thermally conductive grease, or thermally conductive rubber.

In some embodiments, the temperature adjustment element may include a heater or a Peltier element.

In one embodiment, the material from which the sample stage is made may include fused silica or Invar.

In one embodiment, the material that makes up the sample stage may have thermal rectification properties.

In one embodiment, movement of the sample stage due to thermal expansion or contraction may be suppressed.

In some embodiments, the temperature adjustment elements may be controlled by multiple computer programs.

Another aspect of the present disclosure is a sample measurement device. The sample measurement device includes any one of the sample observation stages described above and a nano-measurement device.

In one embodiment, the nano-metrology device may include any of an atomic force microscope, an optical microscope, a laser microscope, an electron microscope, or a nanoindenter.

In some embodiments, the nano-metrology device may analyze rheology.

In some embodiments, the nano-metrology device may analyze at least one of the elastic modulus and hardness.

In some embodiments, the nano-measurement device may include multiple nano-measurement devices.

In addition, any combination of the above components, and conversions of the expressions of this disclosure between methods, devices, systems, recording media, computer programs, etc., are also valid aspects of this disclosure.

According to the present disclosure, it is possible to provide a sample observation stage that can heat or cool a sample while suppressing thermal expansion or contraction of the sample stage in nano-measurement.

FIG. 2 is a side view illustrating the sample observation stage according to the first embodiment. FIG. 1 is a side view showing a schematic diagram of a conventional sample observation stage. FIG. 11 is a side view illustrating a sample measurement device according to a second embodiment. FIG. 1 is a side view showing a schematic diagram of a conventional sample observation stage used in a verification experiment. FIG. 2 is a side view showing a schematic diagram of a sample observation stage of Example 1 used in a verification experiment. FIG. 13 is a side view showing a schematic diagram of a sample observation stage of Example 2 used in a verification experiment. 13 is a graph showing an experimental result when a conventional sample observation stage is used. 13 is a graph showing experimental results when the sample observation stage of Preparation Example 1 is used. 13 is a graph showing experimental results when the sample observation stage of Example 2 was used. 1 is a graph showing the change in nano-gaps over time from 10,000 seconds to 10,100 seconds after heating for Preparation Example 1 and Preparation Example 2.

The present disclosure will be described below with reference to the drawings based on preferred embodiments. In the embodiments and modified examples, identical or equivalent components and parts are given the same reference numerals, and duplicated explanations will be omitted as appropriate. The dimensions of the parts in each drawing are enlarged or reduced as appropriate for ease of understanding. Some parts that are not important for explaining the embodiments are omitted in each drawing. Terms including ordinal numbers such as first and second are used to describe various components, but these terms are used only for the purpose of distinguishing one component from other components, and the components are not limited by these terms.

[First embodiment]
1 is a side view showing a schematic diagram of a sample observation stage 1 according to a first embodiment of the present disclosure. The sample observation stage 1 includes a temperature adjustment element 11, a sample stage 21, a heat medium 31, a base 41, a fixing jig 51, and a heat insulating material 61. A sample 91 is placed on the sample stage 21.

The temperature adjustment element 11 is an element for heating or cooling the sample 91 to enable measurement of the temperature dependence of the sample 91, etc.

As an example, the temperature adjustment element 11 may include a heater for heating the sample, or a Peltier element for heating or cooling the sample.

The temperature adjustment element 11 may be controlled by multiple computer programs.

The sample stage 21 is a stage on which the sample 91 is placed and observed, and is made of a thin material with a low thermal expansion coefficient (i.e., hard). The sample stage 21 is made of a material with a certain thermal conductivity so that heat can be transferred between the temperature adjustment element 11 and the sample 91.

As an example, the material constituting the sample stage 21 may include quartz glass or Invar.

Alternatively, the material constituting the sample stage 21 may have thermal rectification properties.

The heat medium 31 is placed between the temperature adjustment element 11 and the sample stage 21. The heat medium 31 is made of a thermally conductive material so that heat is efficiently transferred between the temperature adjustment element 11 and the sample 91. Furthermore, the heat medium 31 is made of a flexible material so that it can deform when heated or cooled by the temperature adjustment element 11.

The sample stage 21 has a low thermal expansion coefficient and when heated or cooled by the temperature control element 11, it deforms very little compared to the heat medium 31, or does not deform at all.

As described above, heat is transferred between the temperature adjustment element 11 and the sample 91 via the sample stage 21 and the heat medium 31.

As an example, the heat medium 31 may be made of a material such as liquid metal, thermally conductive grease, or thermally conductive rubber.

The base 41 supports the temperature adjustment element 11 from below.

The fixing jig 51 supports the sample stage 21 from below.

The insulating material 61 is disposed between the base 41 and the fixture 51 to prevent heat from being transferred from the base 41 to the fixture 51 (and therefore from the base 41 to the sample stage 21).

In the sample observation stage 1, fluctuations in the sample stage 21 due to thermal expansion or thermal contraction may be suppressed.

Below, the operation of the sample observation stage 1 will be explained using the example of heating the sample 91 using the temperature adjustment element 11.

When the temperature adjustment element 11 operates, heat from the temperature adjustment element 11 is transferred to the heat medium 31. Because the heat medium 31 is made of a thermally conductive material, heat from the temperature adjustment element 11 is transferred to the sample stage 21. Furthermore, because the heat medium 31 is made of a flexible material, it deforms when heated. Therefore, the heat medium 31 exerts almost no force on the sample stage 21.

The sample stage 21 is made of a thin material with a certain degree of thermal conductivity, so the heat from the heat medium 31 is transferred to the sample 91. As a result, the sample 91 is subjected to physical or chemical effects due to the heat. Therefore, the temperature dependence of the sample 91 can be measured using an externally installed nano-measuring device or the like.

On the other hand, the sample stage 21 is made of a hard, thin material with a low thermal expansion coefficient. Because of this and the fact that the sample stage 21 does not receive any force from the heat medium 31 due to its flexibility, the sample stage 21 is only slightly or not at all deformed by heat.

Therefore, even if the sample 91 is heated by the temperature adjustment element 11, thermal expansion or contraction of the stage surface of the sample stage 21 is suppressed, and temporal fluctuations in the distance between the nano-measurement device and the sample 91 are suppressed. Furthermore, adhesion between the sample 91 and the sample stage 21 is maintained. As a result, the accuracy and reliability of the measurement are improved.

The above explanation was for the case where the temperature adjustment element 11 is used to heat the sample 91, but the same applies when the temperature adjustment element 11 is used to cool the sample 91.

As described above, according to this embodiment, in nano-measurement, the sample can be heated or cooled while suppressing the thermal expansion or contraction of the sample stage.

[Comparison with conventional technology]
2 is a side view showing a sample observation stage 2 according to the prior art. The sample observation stage 2 includes a temperature adjustment element 12, a sample stage 22, a base 42, and a fixing jig 52. A sample 92 is placed on the sample stage 22. That is, the sample observation stage 2 differs from the sample observation stage 1 in FIG. 1 in that it does not include a heat medium 31.

In this case, when the temperature adjustment element 12 operates, the heat of the temperature adjustment element 12 is directly transferred to the sample stage 22. As a result, the temperature adjustment element 12 and the sample stage 22 thermally expand or contract, displacing the stage surface of the sample stage 22. As a result, the distance between the external nano-measurement device 82 and the sample 92 fluctuates over time. As a result, the measurement accuracy and reliability decrease.

[Second embodiment]
Fig. 3 is a side view showing a schematic diagram of a sample measurement device 3 according to a second embodiment of the present disclosure. The sample measurement device 3 is a sample measurement device including the sample observation stage 1 of Fig. 1 and a nano measurement device 83. That is, the sample measurement device 3 includes a temperature adjustment element 13 that heats or cools the sample 93, a sample stage 23 on which the sample 93 is placed, a thermally conductive heat medium 33 sandwiched between the temperature adjustment element 13 and the sample stage 23, a base 43, a fixing jig 53, a heat insulating material 63, and the nano measurement device 83. The sample 93 is placed on the sample stage 23.

According to this embodiment, it is possible to heat or cool the sample while suppressing the thermal expansion or contraction of the sample stage, and perform nano-measurements of the sample.

The nano-measurement device 83 may include any of an atomic force microscope, an optical microscope, a laser microscope, an electron microscope or a nanoindenter.

The sample measuring device 3 may be used to analyze rheology.

The sample measuring device 3 may be used to analyze at least one of the elastic modulus or hardness of the sample 93.

The nano-measuring device 83 may be configured to include multiple nano-measuring devices.

[Verification experiment]
In order to verify the effects achieved by the present disclosure, the inventors created two types of sample observation stages (Example 1 and Example 2) according to the embodiments and conducted an experiment to measure the temperature dependence of the sample.

Lubricating oil for automobile engines was used as the sample to be measured. If the temporal fluctuation of the distance between the nano-measurement device and the sample can be suppressed, it will be possible to accurately measure, for example, the temperature dependence of the shear viscoelasticity of the lubricating oil in a nano-gap. When an optical fiber probe is used as the nano-measurement device, a gap resolution of about 0.1 nm is thought to be necessary to detect a shear force with a force sensitivity of 0.1 nN.

[Conventional Example]
4 is a side view showing a schematic diagram of a sample observation stage 4 according to the prior art used in the control experiment. The sample observation stage 4 includes a temperature adjustment element 14, a sample stage 24, a base 44, and a fixing jig 54. In this example, the temperature adjustment element 14 is a heater. A sample 94 (automotive lubricant) is placed directly on the sample stage 24. The sample 94 is measured using a nano-measurement device 84. In this example, the nano-measurement device 84 is an optical fiber probe.

When the temperature adjustment element 14 is heated, the temperature adjustment element 14 and the sample stage 24 deform due to thermal expansion, and the nano-gap between the nano-measurement device 84 and the sample 94 fluctuates over time. For example, it is known that in order to suppress the fluctuation of the nano-gap to 1 nm or less, it is necessary to keep the temperature fluctuation to approximately 0.01°C or less. However, in practice, such precise temperature control is difficult. Therefore, with conventional technology, a gap of several tens of nm occurs.

[Preparation Example 1]
5 is a side view showing a sample observation stage 5 according to Preparation Example 1. The sample observation stage 5 includes a temperature adjustment element 15, a sample stage 25, a heat medium 35, a base 45, and a fixing jig 55. In this example, the temperature adjustment element 15 is a heater. A sample 95 (lubricating oil for automobile engines) is placed directly on the sample stage 25. The sample 95 is measured using a nano-measurement device 85. In this example, the nano-measurement device 85 is an optical fiber probe.

The heat medium 35 is made of thermally conductive rubber and has a hollow cylindrical shape. The thermal conductivity of this thermally conductive rubber is 6.0 W/m·K.

When the temperature adjustment element 15 is heated, the heat medium 35 expands and deforms, collapsing in the radial direction of the cylinder. This reduces the force applied to the sample stage 25. As a result, the nano-gap fluctuations caused by the thermal expansion of the temperature adjustment element 15 are absorbed by the deformation of the heat medium 35.

[Preparation Example 2]
6 is a side view showing a sample observation stage 6 according to Example 2. The sample observation stage 6 includes a temperature adjustment element 16, a sample stage 26, a heat medium 36, a base 46, and a fixing jig 56. In this example, the temperature adjustment element 16 is a heater. A sample 96 (lubricating oil for automobile engines) is placed directly on the sample stage 26. The sample 96 is measured using a nano-measurement device 86. In this example, the nano-measurement device 86 is an optical fiber probe.

The heat medium 36 is gallium, a liquid metal. The heat medium 36 is filled at a predetermined volumetric rate (less than 100%) in a housing placed between the temperature adjustment element 16 and the sample stage 26. The thermal conductivity of gallium is 40.8 W/m·K. This is 6.8 times the thermal conductivity of the thermally conductive rubber used in Example 1.

When the temperature adjustment element 16 is heated, the heat medium 36 expands and fills the space inside the housing. The top surface of the heat medium 36 comes into contact with the sample stage 26. This transfers the heat of the temperature adjustment element 16 to the sample stage 26. On the other hand, since the heat medium 36 is gallium, a liquid metal, it is extremely flexible and exerts only a small force on the sample stage 25. As a result, the nano-gap fluctuations caused by the thermal expansion of the temperature adjustment element 16 are absorbed by the expansion of the heat medium 36.

Figure 7 shows the variation in nano-gap when using the conventional sample observation stage 4. The horizontal axis is time (unit: seconds), and the vertical axis is the vertical size of the nano-gap.

Figure 7 shows the results when the heating temperature was set to 40°C. It can be seen that the size of the nano-gap fluctuates between approximately 40 nm and approximately 200 nm in a cycle of approximately 30 seconds after heating. Such fluctuations can cause a decrease in the accuracy and reliability of the measurement.

Figure 8 shows the variation in nanogap when using the sample observation stage 5 according to the first example. The horizontal axis is time (unit: seconds), and the vertical axis is the vertical size of the nanogap.

Figure 8 shows the results when the heating temperatures were set to 40°C, 60°C, and 80°C. The size of the nanogaps peaks 550 seconds after heating, then gradually decreases and becomes almost stable between 12,000 and 16,000 seconds. In this respect, it differs greatly from the case of Figure 7. In other words, the stability of the nanogaps is greatly improved compared to the conventional example. However, even after reaching a stable state, there is still room for improvement in that temporal fluctuations remain, especially at high temperatures.

Figure 9 shows the variation in nano-gap when using the sample observation stage 6 according to the second example. The meaning and units of the horizontal and vertical axes are the same as those in Figure 8.

As with Figure 8, Figure 9 shows the results when the heating temperature was set to 40°C, 60°C, and 80°C. After heating, the size of the nanogap continues to increase, and then becomes almost stable between 5,000 and 8,000 seconds. Compared to Figure 8, Figure 9 shows that the temporal fluctuations after reaching a stable state are much smaller.

Figure 10 shows the change in nanogap over time from 10,000 seconds to 10,100 seconds after heating for Preparation Example 1 and Preparation Example 2 (heating temperature: 80°C). As shown in the figure, in Preparation Example 1, the nanogap gradually increases while fluctuating by a few nm. On the other hand, in Preparation Example 2, the nanogap maintains a constant size with fluctuations kept to less than 1 nm. In other words, Preparation Example 2 meets the condition of nanogap fluctuations of less than 1 nm, which is the target of nano measurement.

As mentioned above, the difference in the variation of the nano-gaps between Example 1 and Example 2 is thought to be mainly due to the difference in the thermal conductivity of the heat transfer medium.

[Each aspect of the present disclosure]
The following summarizes each aspect of the present disclosure: A sample observation stage according to one aspect of the present disclosure is a sample observation stage for nano-measurement capable of heating or cooling a sample, and includes a temperature adjustment element for heating or cooling the sample, a sample stage on which the sample is placed, and a heat medium having thermal conductivity and flexibility that is sandwiched between the temperature adjustment element and the sample stage.

According to this aspect, it is possible to provide a sample observation stage that can heat or cool a sample while suppressing thermal expansion or contraction of the sample stage in nano-measurement.

In one embodiment, the material constituting the heat transfer medium includes either liquid metal, thermally conductive grease, or thermally conductive rubber.

According to this aspect, it is possible to identify suitable materials and create a heat transfer medium.

In one embodiment, the temperature adjustment element includes a heater or a Peltier element.

According to this aspect, it is possible to identify suitable materials and create a temperature adjustment element.

In one embodiment, the material that makes up the sample stage includes quartz glass or Invar.

According to this aspect, it is possible to identify a suitable material and create a sample stage.

In one embodiment, the material that makes up the sample stage has thermal rectification properties.

This aspect allows the sample stage to have thermal rectification properties, expanding the range of applications.

In one embodiment, movement of the sample stage due to thermal expansion or contraction is suppressed.

This aspect improves the measurement accuracy and reliability of the temperature dependence of the sample in nano-measurement.

In one embodiment, the temperature adjustment element is controlled by multiple computer programs.

This aspect allows the temperature of the temperature control element to be controlled with high precision.

A sample measurement device according to one embodiment of the present disclosure includes a sample observation stage according to any of the above embodiments and a nano-measurement device.

According to this aspect, it is possible to heat or cool the sample while suppressing the thermal expansion or contraction of the sample stage, and perform nano-measurement of the sample.

In one embodiment, the nano-measurement device includes any of an atomic force microscope, an optical microscope, a laser microscope, an electron microscope, or a nanoindenter.

According to this aspect, it is possible to identify a suitable nano-measurement device and manufacture a sample measurement device.

In one embodiment, the sample measurement device is used to analyze rheology.

According to this aspect, highly accurate rheological analysis can be achieved through nano-measurement.

In one embodiment, the sample measurement device is used to analyze the elastic modulus or hardness of a sample.

According to this aspect, the elastic modulus or hardness of a sample can be analyzed with high accuracy by nano-measurement.

In one embodiment, the nano-measurement device includes multiple nano-measurement devices.

According to this aspect, it is possible to achieve highly accurate nano-measurement using multiple nano-measurement devices.

The above describes several embodiments of the present disclosure. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications and changes are possible within the scope of the claims of the present disclosure, and that such modifications and changes are also within the scope of the claims of the present disclosure. Therefore, the descriptions and drawings in this specification should be treated as illustrative rather than restrictive.

Any combination of the above-described embodiments and modifications is also useful as an embodiment of the present disclosure. A new embodiment resulting from the combination has the combined effects of each of the combined embodiments and modifications.

When understanding the technical ideas that abstract the embodiments and variations, the technical ideas should not be interpreted as being limited to the contents of the embodiments and variations. The embodiments and variations described above are merely illustrative examples, and many design changes are possible, such as changing, adding, or deleting components. In the embodiments, the contents in which such design changes are possible are emphasized by adding the notation "embodiment". However, it goes without saying that design changes are also permitted even in contents that are not so notated.

The sample observation stage and sample measurement device disclosed herein can be used in nano-measurements to heat or cool a sample and measure its temperature dependence, etc.

1. Sample observation stand,
2. Sample observation table,
3. Sample measuring device,
4. Sample observation stand,
5. Sample observation stand,
6. Sample observation stand,
11...Temperature adjustment element,
12...Temperature adjustment element,
13...Temperature adjustment element,
14. Temperature adjustment element,
15...Temperature adjustment element,
16...Temperature adjustment element,
21: Sample stage
22: Sample stage,
23: Sample stage,
24: Sample stage,
25: Sample stage,
26: Sample stage,
31. Heat transfer medium,
33. Heat transfer medium,
35. Heat transfer medium,
36... Heat transfer medium,
41: Base,
42: Base,
43... base,
44: Base,
45... base,
46: Base,
51: Fixing jig,
52: Fixing jig,
53: Fixing jig,
54: Fixing jig,
55: Fixing jig,
56: Fixing jig,
61. Thermal insulation material,
63. Thermal insulation material,
82: Nano measurement device,
83. Nano measurement device,
84. Nano measurement device,
85. Nano measurement device,
86: Nano measurement device,
91... Sample,
92. Sample,
93. Sample,
94. Sample,
95. Sample,
96...Sample.

Claims (12)

A sample observation stage for nano-measurement capable of heating or cooling a sample,
A temperature control element for heating or cooling the sample;
A sample stage on which the sample is placed;
a heat medium having thermal conductivity and flexibility, which is disposed between the temperature control element and the sample stage;
Equipped with
A sample observation stage, characterized in that the thermal conductivity of the heat medium is higher than the thermal conductivity of the sample stage. The sample observation stage according to claim 1, characterized in that the material constituting the heat medium includes any one of liquid metal, thermally conductive grease, and thermally conductive rubber. The sample observation stage according to claim 1 or 2, characterized in that the temperature adjustment element includes a heater or a Peltier element. The sample observation stage according to claim 1 or 2, characterized in that the material constituting the sample stage includes quartz glass or invar. The sample observation stage according to claim 1 or 2, characterized in that the material constituting the sample stage has thermal rectification properties. The sample observation stage according to claim 1 or 2, characterized in that the movement of the sample stage due to thermal expansion or thermal contraction is suppressed. The sample observation stage according to claim 1 or 2, characterized in that the temperature adjustment element is controlled by a plurality of computer programs. A sample observation stage according to claim 1 or 2;
A nano-measuring device;
A sample measuring device comprising: The sample measurement device according to claim 8, characterized in that the nano-measurement device includes any one of an atomic force microscope, an optical microscope, a laser microscope, an electron microscope, and a nanoindenter. The sample measurement device according to claim 8, characterized in that it analyzes rheology. The sample measurement device according to claim 8, characterized in that at least one of the elastic modulus and hardness is analyzed. The sample measurement device according to claim 8, characterized in that the nano-measurement device includes a plurality of nano-measurement devices.

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