Dielectric constant measuring device and dielectric constant measuring method

Abstract

The present invention comprises: a probe having a probe body, a flexible portion formed at one end of the probe body and made of a flexible material, and a conductive film made of a flexible conductive material, covering a surface of the flexible portion, and electrically connected to the probe body; a probe pressing means for pressing the probe toward an object to be measured by an arbitrary pressing amount during dielectric constant measurement to deform the flexible portion and the conductive film; a capacitance measuring instrument electrically connected to the probe; and a calculation control unit for calculating a dielectric constant of the object to be measured on the basis of a capacitance value measured by the capacitance measuring instrument.

Description

Dielectric constant measuring device, dielectric constant measuring method

[0001] The present invention relates to a dielectric constant measuring device and a dielectric constant measuring method using the same. This application claims priority based on Japanese Patent Application No. 2024-180379 filed in Japan on October 15, 2024, and incorporates its content herein by reference.

[0002] Conventionally, when measuring the dielectric constant of a measurement object such as an insulating material or a semiconductor material, for example, the capacitor method of forming electrodes on one surface and the other surface of the measurement object is common. On the other hand, the probe electrode method of measuring the dielectric constant with a measuring instrument such as an LCR meter by contacting a probe without forming an electrode on one surface is known.

[0003] For example, in Patent Document 1, a probe and a ring-shaped electrode surrounding the probe are formed above a measurement object placed on a stage, and when the probe is brought into contact with the surface of the measurement object, based on the capacitance generated in a minute region of the measurement object, a dielectric constant measuring device for measuring the dielectric constant of the measurement object is disclosed.

[0004] Further, in Patent Document 2, a semiconductor wafer test system is described in which a measurement object having a dielectric layer is placed, and the capacitance in a state where a contact means having a tip of a partially spherical conductive surface is separated from the upper surface of the dielectric layer, and the capacitance when the contact means is brought close to the upper surface to deform and contact the layer of water and organic substances on the upper surface to form a contact region, and the dielectric constant of the measurement object is obtained from the capacitance when an electrical stimulus is applied in that state.

[0005] The probe electrode methods described in Patent Documents 1 and 2 have advantages other than the fact that measurement can be easily performed, such as the ability to examine the in-plane distribution of characteristics in detail, which is not available in the capacitor method. However, existing probe electrode methods are easily affected by parasitic capacitances such as stray capacitance, and it is difficult to obtain sufficient measurement accuracy.

[0006] To address the effects of stray capacitance mentioned above, for example, Patent Document 3 discloses a method for measuring capacitance while applying excitation with a predetermined amplitude in the Z direction to a probe or the object to be measured, and then calculating the differential value of capacitance (differential capacitance) in relation to the distance between the probe and the lever portion of the cantilever and the surface of each object to be measured by taking the difference of the excitation amplitude.

[0007] Japanese Patent Publication No. 2008-046090, Japanese Patent Publication No. 2005-197697, Japanese Patent Publication No. 2011-053154

[0008] However, although the method disclosed in Patent Document 3 can resolve the effect of stray capacitance, for high dielectric constant materials, the differential capacitance gradually saturates as the dielectric constant increases, resulting in a significant decrease in measurement sensitivity.

[0009] This invention was proposed in view of the above-mentioned problems, and aims to provide a dielectric constant measuring device that can accurately measure the dielectric constant of an object to be measured, even if the object has a high dielectric constant, while eliminating the influence of stray capacitance, and a dielectric constant measuring method using the same.

[0010] To solve the above problems, a dielectric constant measuring device and dielectric constant measuring method of one embodiment of the present invention propose the following means: (1) A dielectric constant measuring device of embodiment 1 of the present invention is a dielectric constant measuring device for measuring the dielectric constant of an object to be measured, comprising: a probe body; a flexible portion made of a flexible material formed at one end of the probe body; and a conductive film made of a flexible conductive material that covers the surface of the flexible portion and is electrically connected to the probe body; a probe pressing means for pressing the probe toward the object to be measured by an arbitrary amount of pressure during dielectric constant measurement to flexibly deform the flexible portion and the conductive film; a capacitance measuring instrument electrically connected to the probe; and a calculation control unit that calculates the dielectric constant of the object to be measured based on the capacitance value measured by the capacitance measuring instrument.

[0011] (2) Aspect 2 of the present invention is the dielectric constant measuring device of aspect 1, wherein the calculation control unit calculates the dielectric constant based on the relationship between the capacitance value and the pressing amount.

[0012] (3) Embodiment 3 of the present invention is a dielectric constant measuring device according to Embodiment 1 or 2, wherein the probe body is a high-frequency waveguide.

[0013] (4) Embodiment 4 of the present invention further comprises a dielectric constant measuring device according to any one of embodiments 1 to 3, wherein a network analyzer connected to the probe is further included.

[0014] (5) Embodiment 5 of the present invention further comprises a dielectric constant measuring apparatus according to any one of embodiments 1 to 4, wherein the probe and the object to be measured are moved relative to each other along a direction perpendicular to the direction in which the probe is pressed.

[0015] (6) A dielectric constant measurement method according to embodiment 6 of the present invention is a dielectric constant measurement method using a dielectric constant measuring device according to any one of embodiments 1 to 5, comprising at least: a first measurement step of pressing the probe against the object to be measured with a first pressing amount using the probe pressing means to bring the conductive film and the object to be measured into contact with a first contact area and then obtaining a first capacitance value; a second measurement step of pressing the probe against the object to be measured with a second pressing amount which is an increase from the first pressing amount using the probe pressing means to bring the conductive film and the object to be measured into contact with a second contact area which is larger than the first contact area and then obtaining a second capacitance value; and a calculation step of calculating the dielectric constant of the object to be measured based on the first capacitance value, the second capacitance value, the first pressing amount, and the second pressing amount.

[0016] (7) Embodiment 7 of the present invention is a dielectric constant measurement method of Embodiment 6, further comprising a calibration step, which is a step after the calculation step, in which the dielectric constant of the object to be measured calculated based on the capacitance value obtained by measuring using a reference object whose dielectric constant is known.

[0017] (8) Embodiment 8 of the present invention is the dielectric constant measurement method of Embodiment 6 or 7, wherein the first pressing amount and the second pressing amount are changed at a predetermined period and the first measurement step and the second measurement step are repeated.

[0018] (9) Embodiment 9 of the present invention is a dielectric constant measurement method according to any one of embodiments 6 to 8, wherein in the calculation step, the dielectric constant of the object to be measured is calculated by further using the value of the thickness of the object to be measured along the direction in which the probe is pressed.

[0019] (10) Embodiment 10 of the present invention is a dielectric constant measurement method according to any one of embodiments 6 to 9, further comprising a moving step of moving the probe and the object to be measured relative to each other along a direction perpendicular to the direction in which the probe is pressed, thereby measuring the dielectric constant distribution on the surface of the object to be measured.

[0020] The present invention provides a dielectric constant measuring device that can easily and accurately measure the dielectric constant of a material without processing the material to be measured, with a simple configuration, and a dielectric constant measuring method using the same.

[0021] This is a schematic diagram showing the dielectric constant measuring device of the first embodiment of the present invention. This is a flowchart showing the dielectric constant measuring method of the first embodiment step by step. This is an explanatory diagram schematically showing the movement of the probe according to the dielectric constant measuring method. This is a graph showing the relationship between the probe pressure Z and capacitance C. This is a schematic diagram showing the dielectric constant measuring device of the second embodiment of the present invention. This is a schematic diagram showing the dielectric constant measuring device of the third embodiment of the present invention. This is a schematic diagram showing the dielectric constant measuring device of the fourth embodiment of the present invention. This is an explanatory diagram showing the calculation model used in the example. This is a graph showing the results of the example. This is a graph showing the results of the example. This is a graph showing the results of the example.

[0022] Hereinafter, with reference to the drawings, a dielectric constant measuring device according to one embodiment of the present invention and a dielectric constant measuring method using the same will be described. The embodiments shown below are described specifically to allow for a better understanding of the spirit of the invention and do not limit the present invention unless otherwise specified. Furthermore, the drawings used in the following description may be enlarged for convenience in order to make the features of the present invention easier to understand, and the dimensional ratios of each component may not be the same as in reality.

[0023] [First Embodiment] Figure 1 is a schematic diagram showing a dielectric constant measuring device according to the first embodiment of the present invention. The dielectric constant measuring device 10 of this embodiment includes a probe 11 that is brought into contact with the object to be measured M during measurement, a probe pressing means 12 that presses the probe 11 against the object to be measured M, a capacitance measuring device 13 that is electrically connected to the probe 11 and has a built-in AC voltage source that applies an AC voltage to the object to be measured M and measures the current from the object to be measured M, and a calculation control unit 14. Note that the capacitance measuring device 13 may use separate devices for the AC power supply and the function of measuring the current.

[0024] The probe 11 has, for example, a rod-shaped probe body 21 made of a conductive material. The conductive material constituting the probe body 21 may be any conductive metal, such as copper, aluminum, silver, iron, and alloys containing these. The probe body 21 may be made of a material other than a conductive material, as long as it can be electrically connected to the capacitance measuring instrument 13. Such a probe body 21 may be a rod-shaped body, for example a cylindrical rod, with a diameter that does not deform, such as bending, when the probe 11 is pressed against the object to be measured M during dielectric constant measurement.

[0025] A flexible portion 22 made of a flexible material is formed at one end of the rod-shaped probe body 21. The flexible material constituting the flexible portion 22 may be a flexible polymer material that can be deformed and restored, such as a soft resin or rubber. Alternatively, the flexible material may be filled with powder or the like. The side of the flexible portion 22 that contacts one end of the probe body 21 has a circular end face, and is formed to protrude forward from this end face in a partially spherical or hemispherical shape. The flexible portion 22 is shaped such that, after contact with the object to be measured M, the contact area increases by a certain amount with respect to the amount of pressure applied in the vertical direction, and is preferably hemispherical. The diameter of the joint portion of the flexible portion 22 with respect to the probe body 21 may be, for example, about 1 mm to 10 mm.

[0026] Furthermore, a conductive film 23 is formed on the surface of the flexible portion 22, covering the flexible portion 22. This conductive film 23 is made of a material that is flexible enough to deform together with the flexible portion 22 during measurement, and also has conductivity. The constituent material of the conductive film 23 may be, for example, a thin metal film such as gold, copper, aluminum, or silver.

[0027] These conductive films 23 are in contact with the conductive probe body 21 at one end of the probe body 21, so as to be electrically connected to the probe body 21. The conductive films 23 can be formed, for example, by vapor deposition of a metal material so as to cover the surface of the flexible portion 22, which is made of a soft resin or rubber. In the following description, the flexible portion 22 and the conductive film 23 covering it may be referred to as the flexible measuring portion 25.

[0028] The probe pressing means 12 is composed of one or more actuators, including, for example, a general actuator such as an electromagnetic motor or a piezoelectric actuator that expands and contracts in response to voltage application. In such a probe pressing means 12, the pressing amount, which is the length to which the probe 11 is lowered toward the object M to be measured, is set according to a control signal that drives the electromagnetic motor or an applied voltage that expands and contracts the piezoelectric actuator.

[0029] The calculation control unit 14 may consist of, for example, a personal computer equipped with a CPU and memory, and an interface that controls the probe pressing means 12 and receives measurement signals from the capacitance meter 13. In the dielectric constant measurement method described later, this calculation control unit 14 controls the extension length of the probe pressing means 12 according to the amount of pressure applied to the probe 11 during measurement. Based on the measurement signal (capacitance value signal) received from the capacitance meter 13, it calculates at least the dielectric constant of the object M to be measured, and further calculates the dielectric loss, and outputs the value of the dielectric constant.

[0030] Next, the dielectric constant measurement method of this embodiment will be described using the dielectric constant measuring device 10 configured as in the embodiment described above. Figure 2 is a flowchart showing the dielectric constant measurement method of this embodiment step by step. Figure 3 is an explanatory diagram schematically showing the movement of the probe in the dielectric constant measurement method of this embodiment.

[0031] When calculating the dielectric constant and dielectric loss of an object to be measured using the dielectric constant measuring device 10, first, the object to be measured M is placed on the stage (not shown) of the dielectric constant measuring device 10 (Figure 3(a): Placement step S1). The object to be measured M can be measured in its current state, and there is no need for pre-processing such as attaching electrodes. The thickness of the object to be measured M should be measured in advance when measuring the dielectric constant.

[0032] Examples of the object to be measured M include semiconductor wafers and dielectric materials such as ceramics. Furthermore, it is preferable that the object to be measured M has sufficient rigidity to prevent it from denting when the flexible measuring portion 25 of the probe 11 is pressed against it during the first and second measurement steps described later. It is also preferable that the surface of the object to be measured M be flat for accurate measurement.

[0033] Next, the calculation control unit 14 of the dielectric constant measuring device 10 is operated to set the first and second pressing amounts. The pressing amount here can be, for example, the length of descent from the state in which the most protruding point of the hemispherical flexible measuring section 25 is in contact with the object to be measured M (the lowest position in which the flexible measuring section 25 does not deform).

[0034] The calculation control unit 14 first operates the probe pressing means 12 based on the set value of the first pressing amount Z1, and extends it downward by Z1 by applying a voltage, so that the probe 11 fixed to the probe pressing means 12 descends downward by the length of Z1.

[0035] Thus, when the probe 11 descends downward by a length Z1 from a state where the tip of the flexible measuring portion 25 of the probe 11 is in contact with the object to be measured M, the conductive film 23 constituting the flexible measuring portion 25 bends (concave) due to the deformation of the flexible portion 22, which has flexibility, so that the shape of the contact portion with the object to be measured M becomes circular. As a result, the conductive film 23 comes into contact with the object to be measured M with a first contact area.

[0036] Then, once the probe 11 has finished descending, the capacitance measuring instrument (e.g., LCR meter) 13 measures the capacitance C1 via the probe 11 (Figure 3(b): First measurement step S2). The calculation control unit 14 stores the obtained capacitance C1 in memory. The capacitance measuring instrument 13 may be configured as an impedance analyzer or a capacitance sensor using an LC resonant circuit.

[0037] Next, the calculation control unit 14 operates the probe pressing means 12 based on the set value of the second pressing amount Z2, and extends it further downward from Z1 to Z2 by applying voltage, so that the probe 11 fixed to the probe pressing means 12 descends by a length of Z2.

[0038] Thus, as the probe body 21 of the probe 11 is lowered from the first pressing amount Z1 to the second pressing amount Z2, the conductive film 23 constituting the flexible measuring portion 25 bends (concave) due to further deformation of the flexible portion 22, causing the shape of the contact portion with the object to be measured to form an even larger circle than at the first pressing amount Z1. In other words, the contact area of ​​the conductive film 23 with the object to be measured M increases (second contact area).

[0039] Then, once the probe 11 has finished descending, the capacitance measuring instrument 13 measures the capacitance C2 at the second pressing amount Z2 via the probe 11 (Figure 3(c): Second measurement step S3). The calculation control unit 14 stores the obtained capacitance C2 in memory.

[0040] The calculation control unit 14 creates a straight line showing the relationship between the probe 11's pressing amount ΔZ (= Z2 - Z1) and the capacitance change ΔC (= C2 - C1) based on the capacitance C1 at the first pressing amount Z1 and the capacitance C2 at the second pressing amount Z2 obtained in this way, and calculates the dielectric constant of the object to be measured M from the slope of the straight line (ΔC / ΔZ) (calculation step S4).

[0041] For example, as shown in Figure 4, the straight line showing the relationship between the probe pressure ΔZ and the capacitance change ΔC has a gentler slope (low dielectric constant) for objects with a low dielectric constant, and a steeper slope for objects with a higher dielectric constant.

[0042] From the change rates of the capacitance C1 at the first pressing amount Z1 and the capacitance C2 at the second pressing amount Z2, the value of the dielectric constant of the object M to be measured can be obtained according to the thickness of the object M to be measured.

[0043] Thus, in this embodiment, since the dielectric constant is calculated from the change amount (change rate) rather than the absolute value of the capacitance, the parasitic capacitance component is canceled out, and it is possible to determine the dielectric constant with high precision without being affected by the parasitic capacitance. In addition, since the measurement is performed with the probe 11 always in contact with the object M to be measured, it is possible to accurately measure the dielectric constant of the object M to be measured even if it is an object with a high dielectric constant.

[0044] In such a measurement method, by using an object M to be measured with a known dielectric constant and measuring in advance the change rates of the capacitance C1 at the first pressing amount Z1 and the capacitance C2 at the second pressing amount Z2, the relationship between ΔC / ΔZ and the dielectric constant can be calibrated. Such a method is particularly effective when the flexible part is not an ideal hemispherical shape or when it is difficult to accurately determine the radius of curvature of the flexible part.

[0045] Further, in this embodiment, at least the first measurement step S2 and the second measurement step S3 are performed when measuring the dielectric constant. In addition to this, the pressing amount ΔZ of the probe can be increased to measure the capacitance change ΔC, etc., and the pressing amount of the probe can be made three or more steps, and the capacitance can be measured respectively. Thereby, the measurement accuracy of the dielectric constant of the object M to be measured can be further improved.

[0046] [Second Embodiment] FIG. 5 is a schematic configuration diagram showing a dielectric constant measuring device according to the second embodiment of the present invention. The same components as those in the first embodiment are given the same numbers, and redundant explanations are omitted. The dielectric constant measuring device 30 of this embodiment uses a coaxial probe (high-frequency waveguide) as the probe body 41 of the probe 31. For this probe 31, a high-frequency incident wave in the GHz band, for example, is input from the network analyzer 33, and a reflected wave corresponding to the capacitance C1 or C2 is received.

[0047] In the dielectric constant measuring device 30 of the second embodiment having such a configuration, a high-frequency incident wave (for example, microwave or millimeter wave) is input to the coaxial probe 31, and the reflected wave corresponding to the capacitances C1 and C2 is received by the network analyzer 33, so that the dielectric constant and dielectric loss of the object under measurement M in the high-frequency band can be measured with high accuracy and simply.

[0048] [Third Embodiment] FIG. 6 is a schematic configuration diagram showing a dielectric constant measuring device of the third embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals, and redundant descriptions are omitted. The dielectric constant measuring device 50 of the present embodiment includes a stage 51 on which the object under measurement M is placed and which is moved along a direction F perpendicular to the pressing direction of the probe 11.

[0049] In the dielectric constant measuring method using such a dielectric constant measuring device 50, at the time of measurement, the first measurement step S2, the second measurement step S3, and a moving step in the first embodiment are performed. That is, the first measurement step S2 and the second measurement step S3 are performed at an arbitrary measurement point of the object under measurement M, and based on the obtained capacitance, the dielectric constant of the object under measurement M at this measurement point is calculated and the result is stored.

[0050] Then, the stage 51 is moved by an arbitrary width in the moving step, and then the capacitance is measured again at the measurement point after this movement by the first measurement step S2 and the second measurement step S3, and the dielectric constant of the object under measurement M is calculated and the result is stored.

[0051] Thus, by repeating the measurement of the dielectric constant - the movement of the object under measurement M - the measurement of the dielectric constant, the distribution of the dielectric constant in an arbitrary direction along the surface of the object under measurement M can be measured. And the smaller the movement width of the object under measurement M in the moving step is set, the higher the measurement density of the capacitance becomes, and more detailed dielectric constant distribution data can be obtained.

[0052] The tip radius of curvature of the flexible measuring section 25 of the probe 11 can be, for example, 0.5 mm to 5 mm. On the other hand, if the measurement sensitivity of the capacitance measuring instrument 15 is sufficiently high, the tip radius of curvature can be set to 0.5 mm or less. The smaller the tip radius of curvature, the higher the spatial resolution with which measurements can be performed. For example, if the tip radius of curvature is set to about 20 nm, the in-plane distribution of dielectric constant in the micrometer to nanoscale region can be measured. One way to realize such measurements using a sharp probe is to use a probe microscope device such as an atomic force microscope.

[0053] In this embodiment, a stage 51 is provided for moving the object to be measured M relative to the probe 11. However, the object to be measured M and the probe 11 only need to be configured to move relative to each other. Alternatively, a probe moving means is provided to move the probe 11 along a direction perpendicular to the pressing direction, thereby moving the probe 11 relative to the object to be measured M, or both the object to be measured M and the probe 11 can be configured to be movable.

[0054] [Fourth Embodiment] Figure 7 is a schematic diagram showing a dielectric constant measuring device according to the fourth embodiment of the present invention. Components similar to those in the second embodiment are given the same numbers, and redundant explanations are omitted. In the dielectric constant measuring device 60 of this embodiment, a lock-in amplifier 65 is further connected to the capacitance measuring instrument 13 of the first embodiment. Furthermore, in this embodiment, the probe pressing means 32 is composed of a coarse-motion electromagnetic actuator 32a and a fine-motion piezoelectric actuator 32b. By applying an AC voltage from the AC power supply 34 to the fine-motion piezoelectric actuator 32b, the fine-motion piezoelectric actuator 32b is extended sinusoidally or periodically, causing the probe 31 to move (vibrate) within a predetermined range of pressure.

[0055] The lock-in amplifier 65 uses the voltage signal of the AC power supply 34, which generates a control signal to extend the micro-movement piezoelectric actuator 32b, as a reference signal, and detects only the measurement signals synchronized with the reference signal from among the signals measured by the capacitance meter 13.

[0056] With this configuration, by detecting only the measurement signal synchronized with the reference signal using the lock-in amplifier 65, the detection accuracy of the change in capacitance based on the measurement signal due to the extension of the micro-movement piezoelectric actuator 32b can be improved, and the dielectric constant of the object M to be measured can be measured more accurately.

[0057] The embodiments 1-4 described above can be combined in any way. For example, a dielectric constant measuring device can be realized by arbitrarily combining a network analyzer (for dielectric constant measurement and dielectric loss measurement in the high frequency band), a lock-in amplifier (for synchronous detection measurement), and a stage for moving the object to be measured (for dielectric constant distribution measurement). In addition, a configuration may be further provided that includes at least a probe with a flexible part, a probe pressing means for pressing the probe against the object to be measured, a capacitance measuring instrument, and a calculation control unit for calculating the dielectric constant of the object to be measured, and that these components are moved more precisely while detecting the measurement signal with higher accuracy.

[0058] Although one embodiment of the present invention has been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be carried out in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

[0059] We conducted a verification of the dielectric constant measurement using the dielectric constant measuring device of the present invention. A simulation was performed using the calculation model shown in Figure 8. In this calculation model, when the flexible measuring part 25 is pressed against the object to be measured M, the deformation caused by the lateral displacement of the pressed portion is considered to be small and is ignored. The amount of indentation D is defined as the distance traveled when the probe 11 is moved downward from the reference position, with the tip of the flexible measuring part 25 beginning to contact the surface of the object to be measured M as the reference point.

[0060] First, Figure 9 shows the relationship between the indentation rate (%) of the probe 11 and the capacitance (pF) when the radius of curvature r of the flexible measuring section 25 is 2 mm and the thickness of the dielectric material M to be measured is 100 mm. Note that the indentation rate (%) referred to here is the value calculated as "(indentation amount D / radius of curvature r) × 100".

[0061] As shown in Figure 9, when the relative permittivity of the dielectric material is changed to 4, 8, 12, 16, and 20, the slope of the relationship between the probe 11 indentation rate (%) and capacitance (pF) becomes steeper as the relative permittivity increases. This demonstrates that by changing the indentation rate of the probe 11 and measuring the capacitance, the permittivity can be calculated from the degree of slope shown in Figure 9.

[0062] Next, under the conditions described above, we investigated the relationship between capacitance change (ΔC) and dielectric constant when the indentation rate (%) was changed from 1% to 2% and from 10% to 11%. The results are shown in Figure 10.

[0063] As shown in Figure 10, when the indentation rate (%) of the probe 11 is changed from 1% to 2% and when it is changed from 10% to 11%, the change in capacitance (ΔC) increases monotonically with respect to the change in dielectric constant. This shows that it is possible to convert the change in capacitance (ΔC) to the dielectric constant. However, when the indentation rate (%) of the probe 11 is changed from 1% to 2% and from 10% to 11%, ΔZ is the same at 1%, but ΔC is different, which indicates that ΔC / ΔZ depends on the first indentation amount Z1. Therefore, when calculating the dielectric constant from ΔC / ΔZ, it is necessary to take into account the value of the first indentation amount Z1.

[0064] As shown in Figure 10, in both cases where the indentation rate (%) of the probe 11 was changed from 1% to 2% and from 10% to 11%, the capacitance change (ΔC) continued to increase almost linearly with respect to the dielectric constant, even in the high dielectric constant region where the dielectric constant exceeds 100. From this, it has been demonstrated that the measurement sensitivity does not decrease even in the high dielectric constant region, and that the dielectric constant can be calculated with almost the same accuracy as in the low dielectric constant region (dielectric constant of 100 or less).

[0065] Next, under the conditions described above, simulations using both a probe model and a parallel plate model were performed for cases where the dielectric thickness was 20 μm, 200 μm, and 500 μm, and the indentation rate (%) was changed from 1% to 2% and from 10% to 11%. The results were then compared. The results are shown in Figure 11.

[0066] As shown in Figure 11, when the dielectric thickness is sufficiently thin, the simulation results in the probe model closely match those of the parallel plate model. However, when the dielectric thickness is thick, the two do not match. This indicates that while the parallel plate model can be used to calculate the dielectric constant when the dielectric thickness is sufficiently thin, it cannot be used when the dielectric thickness is thick, and numerical simulation considering the probe shape is necessary in the dielectric constant calculation process.

[0067] The dielectric constant measuring apparatus and dielectric constant measuring method using the present invention make it possible to accurately measure the dielectric constant and dielectric loss of semiconductor wafers and insulating materials, for example, with a simple configuration. Therefore, it has industrial applicability.

[0068] 10... Dielectric constant measuring device 11... Probe 12... Probe pressing means 13... Capacitance measuring instrument 14... Calculation control unit 21... Probe body 22... Flexible part 23... Conductive film 25... Flexible measuring part M... Object to be measured

Claims

1. A dielectric constant measuring device for measuring the dielectric constant of an object to be measured, comprising: a probe having a probe body; a flexible portion made of a flexible material formed at one end of the probe body; and a conductive film made of a flexible conductive material that covers the surface of the flexible portion and is electrically connected to the probe body; a probe pressing means for pressing the probe toward the object to be measured by an arbitrary amount of pressure during dielectric constant measurement to flexibly deform the flexible portion and the conductive film; a capacitance measuring instrument electrically connected to the probe; and a calculation control unit for calculating the dielectric constant of the object to be measured based on the capacitance value measured by the capacitance measuring instrument.

2. The dielectric constant measuring device according to claim 1, wherein the calculation control unit calculates the dielectric constant based on the relationship between the capacitance value and the amount of pressure.

3. The dielectric constant measuring apparatus according to claim 1 or 2, wherein the probe body is a high-frequency waveguide.

4. The dielectric constant measuring apparatus according to claim 3, further comprising a network analyzer connected to the probe.

5. The dielectric constant measuring apparatus according to claim 1 or 2, further comprising a moving means for moving the probe and the object to be measured relative to each other along a direction perpendicular to the direction in which the probe is pressed.

6. A dielectric constant measurement method using the dielectric constant measuring apparatus according to claim 1 or 2, comprising at least: a first measurement step of pressing the probe against the object to be measured with a first pressing amount using the probe pressing means to bring the conductive film and the object to be measured into contact with a first contact area and then obtaining a first capacitance value; a second measurement step of pressing the probe against the object to be measured with a second pressing amount, which is an increase from the first pressing amount, to bring the conductive film and the object to be measured into contact with a second contact area larger than the first contact area and then obtaining a second capacitance value; and a calculation step of calculating the dielectric constant of the object to be measured based on the first capacitance value, the second capacitance value, the first pressing amount, and the second pressing amount.

7. The dielectric constant measurement method according to claim 6, further comprising a calibration step, which is a post-calculation step, in which the dielectric constant of the object to be measured calculated based on the capacitance value obtained by measuring with a reference object whose dielectric constant is known.

8. The dielectric constant measurement method according to claim 6, wherein the first pressing amount and the second pressing amount are changed at a predetermined period, and the first measurement step and the second measurement step are repeated.

9. The dielectric constant measurement method according to claim 6, wherein the calculation step further uses the value of the thickness of the object to be measured along the direction in which the probe is pressed to calculate the dielectric constant of the object to be measured.

10. The dielectric constant measurement method according to claim 6, further comprising a moving step of moving the probe and the object to be measured relative to each other along a direction perpendicular to the direction in which the probe is pressed, thereby measuring the dielectric constant distribution on the surface of the object to be measured.

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