KR20100083541A - Capacitive load cell, method for fabricating the same and method for measuring the load - Google Patents

Abstract

PURPOSE: A capacitance type load cell, a manufacturing method thereof, and a load gauging method using the same are provided to effectively shield an external stimulus by forming an upper electrode between pillars of an upper substrate. CONSTITUTION: A capacitance type load cell comprises an upper substrate(30) which includes pillars(30A) in which the shape changes according to the delivered load, a lower substrate(31) which supports the upper substrate, and a capacitor(33) which comprises the upper electrode and the lower electrode. The upper electrode is formed on the upper substrate among the adjacent pillar. The lower electrode is formed on the lower substrate while being corresponded to the upper electrode.

Description

CAPACITIVE LOAD CELL, METHOD FOR FABRICATING THE SAME AND METHOD FOR MEASURING THE LOAD}

The present invention relates to a capacitive load cell, a method for manufacturing the same, and a load measuring method using the same, and more particularly, to a capacitive load cell, a method for manufacturing the same, and a load measuring method using the same. It is about.

The present invention is derived from a study conducted as part of the National Research Laboratory project of the Ministry of Education, Science and Technology and the Seoul National University Industry-Academic Cooperation Group. [Task Management No .: R0A-2007-000-10051-0, Task name: Using MEMS and RF technology FORCE sensor development].

A load cell refers to a sensor that converts a load change into an electrical signal and outputs the load. Generally, a strain gauge type load cell that measures a load by measuring a deformation of an elastic body by a strain gage. guage load cell) is used.

Here, the load cell is divided into a pillar type, a bending type, and the like according to the deformation method of the elastic body. The pillar type is a method of measuring the compression amount of the elastic body according to the load applied from the top to the bottom, and is suitable for manufacturing a large load cell, but has a problem of low precision. Bending type (bending type) is a method of measuring the degree of bending of the elastic body, high precision, but there is a problem that it is difficult to manufacture a large capacity load cell.

The structure of the load cell according to the prior art in the paper "Quasi Monoliyhic Silicon Load Cell for Loads up to 1000kg with Insensitivity to Non-homogeneous Load Distributions" published in "MEMS'99, Orlando, Florida, Jan, 17-21,1999." And the matter related to the manufacturing method is described, with reference to this, it will be described below, the structure of the pillar-shaped load cell according to the prior art, a manufacturing method and a load measuring method using the same.

1 is a perspective view showing the structure of a pillar-shaped load cell according to the prior art.

As shown, the load cell has an upper substrate 10 to which a load is applied and a lower substrate 11 supporting the upper substrate 10, and an insulating film is formed between the upper substrate 10 and the lower substrate 11. 12) is interposed.

Here, the upper substrate 10 has a plurality of pillars (10A) formed integrally connected to the upper substrate 10, the plurality of pillars (10A) is a first direction (I-I ') and a second crossing the first direction Arranged in the direction II-II '.

In addition, a capacitor 13 is provided between the adjacent pillars 10A. In this case, the entire upper substrate 10 is used as the upper electrode of the capacitor 13, and the conductive pattern formed on the lower substrate 11 is lowered. Used as an electrode.

In addition, a pad portion 14 for measuring the capacitance of the capacitor 13 is formed around the lower substrate 11, and the upper substrate 10 has a contact hole 15 for exposing the pad portion 14. It is provided. That is, the load cell includes a first region A in which the plurality of pillars 10A and the capacitor 13 are formed, and a second region B in which the pad portion 14 is formed, and the first region A and the first region. The two regions B are connected by the connecting portion 16. Here, the connecting portion is made of a spring or the like.

Looking at the load measurement principle of the load cell having such a structure as follows. First, when a load is applied to the upper substrate 10, the pillar 10A is compressed and the height is changed accordingly, and the distance between the upper electrode and the lower electrode of the capacitor 13 varies according to the height change of the pillar 10A. The capacitance of the capacitor 13 is changed.

Here, the distance change between the upper electrode and the lower electrode according to the load may be expressed by Equation 1 below. Where Δd represents the change in distance between the upper electrode and the lower electrode, F is the load, Ap is the area of the pillar, n _p is the number of pillars, h _p is the pillar height, and E _si is the Young's modulus of silicon. Indicates.

In addition, the capacitance of the load cell may be expressed as Equation 2 below. Where C is the capacitance of the load cell, ε ₀ is the dielectric constant, Ae is the area of the electrode, and d is the distance between the electrodes.

Through this, it can be seen that as the load applied increases, the distance between the upper electrode and the lower electrode decreases, thereby increasing the capacitance of the load cell. Therefore, the load can be calculated by measuring the change in distance between the upper electrode and the lower electrode by measuring the capacitance of the load cell, and it can be processed as a digital signal using a conversion sensor, for example, the AD7746.

FIG. 2 is a cross-sectional view illustrating a process of manufacturing a load cell according to the prior art, and illustrates a cross-sectional view of the first direction I-I ′ of FIG. 1. In particular, (a) of FIG. 2B shows a cross-sectional view of the process, and (b) shows a plan view at the height of the dotted line (III-III ') of (a).

As shown in FIG. 2A, the upper surface U is etched to form an uneven surface so that the pillar scheduled region of the upper surface U of the upper substrate 20 protrudes. Here, the pillar scheduled region refers to a region where pillars are to be formed on the lower surface D of the upper substrate 20 by a subsequent process. As described above, by projecting the pillar scheduled region of the upper surface U of the upper substrate 20, the load applied to the upper substrate 20 may be concentrated on the pillar instead of being transferred to the capacitor.

As illustrated in FIG. 2B, a predetermined depth is etched around the pillar scheduled area of the lower surface D of the upper substrate 20. As a result, a plurality of pillars 20A arranged in the first direction I-I 'and the second direction II-II' are formed. At this time, the upper substrate region 20B between the adjacent pillars 20A is adjacent to the lower electrode formed on the lower substrate 21 by a subsequent process, thereby forming a capacitor.

In addition, a contact hole is formed around the upper substrate 20 in correspondence with the position of the pad portion to be formed on the lower substrate by a subsequent process. Here, the formation of the contact hole is performed simultaneously with the formation of the pillar 20A. The contact hole penetrates through the upper substrate 20 so that the etching depth is deep. Therefore, two DRIE processes are performed to form contact holes.

As shown in FIG. 2C, at the upper surface U of the lower substrate 21, the upper surface U is etched such that an area corresponding to the pillar 20A area of the upper substrate 20 protrudes. That is, the groove portion is formed by etching the region of the lower substrate 21 corresponding to the upper substrate region 20B between the pillars 20A of the upper substrate 20.

Subsequently, after the insulating film 22 is formed on the surface of the result through the oxidation process, the lower electrode 23 is formed in the groove portion. In this case, the pad portion 24 is formed at the edge of the lower substrate 21 instead of the lower electrode 23.

As shown in FIG. 2D, the upper substrate 20 and the lower substrate 21 are bonded to form a load cell. At this time, the pillars 20A of the upper substrate 20 and the protrusions of the lower substrate 21 come into contact with each other, and the area 20B between the pillars 20A of the upper substrate 20 and the lower electrode of the lower substrate 21 are in contact with each other. 23 is placed at the corresponding position. Of course, a dielectric film may be interposed between the lower electrode 23 and the upper electrode 20, and the capacitance of the capacitor changes according to the compression of the pillar 20A.

However, according to the prior art as described above, three problems largely occur in the structure and manufacturing process of the load cell.

First, since the entire upper substrate 10, 20 is used as the upper electrode of the capacitor 13, there is a problem that the influence by the external stimulus is large. Of course, a shielding case may be formed outside the load cell to block some external magnetic poles. However, since the entire upper substrate 10 and 20 are exposed to the upper electrode, there is a limit to effectively blocking the external magnetic poles. .

Second, although the first region A and the second region B are connected to the connecting portion 16, when a load of a predetermined size or more is applied, the connecting portion 16 moves, and thus there is a problem of structural instability. . In particular, when the connecting portion 16 is made of a spring, the spring may move or break, thereby causing an error in the measured value.

Third, the capacitive load cell has pad portions 14 and 24 for measuring the capacitance of the capacitor 13, and forms contact holes 15 and 25 to expose the pad portions 14 and 24. . However, when the contact holes 15 and 25 are formed, there is a process difficulty because the etching depth is deep.

In this regard, the prior art proposes a method of forming the contact holes 15 and 25 by etching the upper substrate 20 by a Deep Reactive Ion Etching (DRIE) process, but accordingly, the pillars 10A and 20A and Since two DRIE processes are required in the process of forming the contact holes 15 and 25, there is a problem that the manufacturing cost increases.

The present invention has been proposed to solve the above problems, and an object of the present invention is to provide a capacitive load cell, a method for manufacturing the same, and a load measuring method using the same, which are suitable for effectively blocking external magnetic poles.

In order to achieve the above object, the present invention provides a capacitive load cell, comprising: an upper substrate including a plurality of pillars whose shape changes according to a load to be transmitted; A lower substrate supporting the upper substrate; And a capacitor including an upper electrode formed on the upper substrate between the adjacent pillars and a lower electrode formed on the lower substrate corresponding to the upper electrode position.

The present invention also provides a method of manufacturing a capacitive load cell, comprising: forming an insulating film on a first substrate; Forming an upper electrode on the insulating layer between the pillar predetermined regions; Forming a dielectric film on the entire structure of the resultant product in which the upper electrode is formed; Forming a plurality of pillars by first etching the dielectric layer, the insulating layer, and the first substrate formed around the pillar predetermined region; Forming a groove by etching a second depth of a region of the second substrate corresponding to the position of the upper electrode formed on the first substrate; Forming a lower electrode in the groove; And forming a capacitor formed between adjacent pillars by bonding the first substrate and the second substrate to each other.

In addition, the present invention is a load measuring method using a capacitive load cell, the upper substrate comprising a plurality of pillars that change in shape depending on the load transmitted, between the lower substrate for supporting the upper substrate and the pillar of the upper substrate Applying a load to the upper substrate of the load cell, the capacitor including an upper electrode formed on the upper substrate of the upper substrate and a lower electrode formed on the lower substrate corresponding to the position of the upper electrode; Changing the capacitance of the capacitor by the compression of the pillar and the bending of the upper substrate according to the load transmitted from the upper substrate; And calculating a load applied to the upper substrate by reading a change in capacitance of the capacitor.

According to the present invention, by forming an upper electrode between adjacent pillars of the upper substrate, it is possible to provide a capacitive load cell suitable for efficiently blocking external magnetic poles. In particular, by grounding the upper substrate, it is possible to minimize the error caused by the external stimulus when measuring the load.

In addition, by forming a pad part on one side of the load cell, a load cell having a stable structure can be formed. In particular, since one side of the upper substrate is cut to expose the pad part, it is not necessary to form a separate contact hole. Accordingly, the manufacturing cost of the load cell can be reduced by reducing the number of DRIE processes in the load cell.

In the following, the most preferred embodiment of the present invention is described. In the drawings, thickness and spacing may be exaggerated for convenience of description. In describing the present invention, well-known structures irrelevant to the gist of the present invention may be omitted. In adding reference numerals to the components of each drawing, it should be noted that the same components as much as possible, even if displayed on different drawings.

3 is a perspective view showing the structure of a load cell according to an embodiment of the present invention.

As shown in the drawing, the load cell includes an upper substrate 30 including a plurality of pillars 30A, the shape of which changes in accordance with a transmitted load, a lower substrate 31 supporting the upper substrate 30, and an adjacent pillar 30A. And a capacitor 33 including an upper electrode formed on the upper substrate 30 between the two substrates and a lower electrode formed on the lower substrate 31 corresponding to the upper electrode position. Here, an insulating film (not shown) may be interposed between the upper substrate 30 and the lower substrate 31.

The upper substrate 30 has a plurality of pillars 30A formed integrally connected to itself, and the pillars 30A are compressed in accordance with the load applied through the upper substrate 30 to change the height, and thus the capacitor The capacitance of 33 is changed. In this case, the plurality of pillars 30A are arranged in the first direction I-I 'and in the second direction II-II' crossing the first direction.

Here, the upper electrode formed on the upper substrate 30 between the adjacent pillars 30A is electrically separated from the upper substrate 30 by an insulating film interposed between the upper substrate 30 and the upper electrode.

At this time, the upper substrate 30 is preferably grounded, and one side of the upper substrate 30 is preferably cut to a predetermined width to expose the pad 34.

The lower substrate 31 has a groove formed by etching an area corresponding to the position of the upper electrode, and the lower electrode is provided in the groove. In addition, one side of the lower substrate 31 is provided with a pad portion 35 for measuring the capacitance of the capacitor 33.

The capacitance of the capacitor 33 is changed according to the compression of the pillar 30A and the degree of warpage of the upper substrate 30 when the load is transferred. The capacitance of the capacitor 33 is changed using the pad part 34. The load can be calculated by measuring.

Here, the capacitor 33 is preferably formed in a region where the deformation of the pillar according to the load applied to the upper substrate 30 is large, and particularly preferably in the center of the capacitive load cell.

Thus, by forming the upper electrode electrically separated from the upper substrate 30, it is possible to block the external magnetic poles more efficiently than in the prior art, it is not necessary to manufacture a separate shielding case. In particular, by grounding the upper substrate 30, it is possible to block the external magnetic pole more efficiently.

In addition, since the upper surface of the upper substrate 30 is formed flat without unevenness, according to the load applied, the upper substrate 30 is compressed and bent. That is, when a load is applied, the pillar 30A is compressed and the upper substrate 30 is bent, so that the total capacitance of the capacitor 33 reflecting both the degree of compression and bending can be measured. Thus, by considering both the degree of compression and the deflection, the load can be measured more precisely than in the conventional load cell.

In addition, a pad portion 34 for measuring the capacitance of the capacitor 33 is formed at one side of the lower substrate 31, and one side 35 of the upper substrate 30 is cut to expose the pad portion 34. Let's do it. In this way, by cutting the one side 35 of the upper substrate 30 to expose the pad 34, there is no need to perform a separate contact hole process, unlike the prior art, it does not include a connection portion load cell of a stable structure Can be formed.

4A to 4F are cross-sectional views illustrating a process of manufacturing a load cell according to an exemplary embodiment of the present invention, and show cross-sectional views in a first direction II-II ′ of FIG. 3. Here, the first substrate 40 corresponds to the upper substrate 30 described above with reference to FIG. 3, and the second substrate 44 corresponds to the lower substrate 31.

As shown in FIG. 4A, an insulating film 41 is formed on the surface of the first substrate 40 through an oxidation process. Here, the insulating film 41 is for electrically separating the upper electrode and the first substrate 40 formed by a subsequent process, preferably made of an oxide film or a nitride film, and has a thickness of 500 to 1500 kPa by a wet oxidation process. It is preferable to be formed. In addition, the first substrate 40 is preferably made of silicon.

Subsequently, after the conductive film is formed on the insulating film 41, the formed conductive film is patterned to form the upper electrode 42 on the insulating film 41 between the pillar regions P.

Here, the conductive film is preferably made of chromium (Cr) or gold (Au), but in the case of chromium (Cr), it is preferably formed to a thickness of 50 to 100 kPa, and in the case of gold (Au), the thickness of 500 to 1500 kPa It is preferable to form.

In addition, the conductive film forming process is preferably performed using an E-gun evaporator.

Subsequently, a capacitor dielectric film 43 is formed on the entire structure of the resultant product in which the upper electrode 42 is formed. Here, the capacitor dielectric film 43 is preferably formed of an oxide film, and the dielectric film 43 forming process is preferably performed by a plasma enhanced chemical vapor deposition (PECVD) process.

As shown in FIG. 4B, after the first mask pattern (not shown) covering the upper electrode 42 is formed on the capacitor dielectric layer 43, the dielectric layer 43 for the capacitor is used as an etch barrier. ) And the insulating layer 41 are etched to expose the pillar scheduled region P of the first substrate 40.

As shown in FIG. 4C, a plurality of arrayed portions in the first direction I-I 'and the second direction II-II' are etched by etching the first depth d1 around the pillar scheduled region P. Referring to FIG. The pillar 40A is formed. Here, the first depth d1 is preferably 100 to 400 μm, and the etching process is preferably performed by a deep reactive ion etching (DRIE) process.

In this case, after forming a second mask pattern (not shown) covering the upper electrode 42 and the pillar region P, the first substrate 40 is formed as an etch barrier using the second mask pattern as a first depth d1. By etching with), a plurality of pillars 30A can be formed. In particular, when the peripheral area of the pillar scheduled area P is etched, the boundary of the pad part scheduled area PAD of the second substrate 44 may be etched together.

As shown in FIG. 4D, a groove is formed by etching the region of the second substrate 44 corresponding to the position of the upper electrode 42 formed on the first substrate 40 to the second depth d2. Here, the second substrate 44 is preferably made of silicon or glass. For example, when the first substrate 40 is made of silicon and the second substrate 44 is made of silicon, the first substrate is made of silicon. More preferably, an insulating film is interposed between the 40 and the second substrate 44.

In this case, the second depth d2 preferably has a value smaller than the first depth d1. For example, when the first depth d1 is 100 μm to 400 μm, the second depth d2 is 1 μm. It is more preferable that it is 3 micrometers.

Subsequently, a lower electrode 45 is formed in the groove, and after forming a conductive film on the entire structure of the resultant groove formed thereon, patterning the formed conductive film corresponds to the upper electrode 42 formed on the first substrate 40. The lower electrode 45 is formed at the position. At this time, one side of the second substrate 44 is formed with a pad portion 46 for measuring the capacitance of the capacitor.

Here, the conductive film is preferably made of chromium (Cr) or gold (Au), but in the case of chromium (Cr), it is preferably formed to a thickness of 50 to 100 kPa, and in the case of gold (Au), the thickness of 500 to 1500 kPa It is preferable to form.

In addition, the conductive film forming process is preferably performed using an E-gun evaporator.

As shown in FIG. 4E, the first substrate 40 and the second substrate 44 are bonded to form a capacitor 47 between adjacent pillars 40A. For example, when the first substrate 40 is made of silicon and the second substrate 44 is made of glass, the first substrate 40 and the second substrate 44 are formed by anodic bonding. In addition, since the bonding process of bonding the first substrate 40 and the second substrate 44 is well known to those skilled in the art, a detailed description thereof will be omitted.

As shown in FIG. 4F, the boundary region of the pad portion 46 is cut to expose the pad portion 46 of the second substrate 44. In this case, since the boundary region is etched to the first depth d1 when the pillar 40A is formed, the boundary region may be easily cut by the blade process. Therefore, there is no need to perform a separate DRIE process.

Next, although not shown in the drawing, it is preferable to ground the first substrate 40. Through this, when measuring the load, it is possible to minimize the error caused by the external stimulus.

5 is a flowchart illustrating a procedure of a load measuring method using a capacitive load cell according to an embodiment of the present invention. Here, specific details of the structure and manufacturing method of the capacitive load cell are the same as described above with reference to FIGS. 3 to 4E.

First, as described above, the upper substrates 30 and 40 including a plurality of pillars whose shape changes according to the transmitted load, the lower substrates 31 and 44 supporting the upper substrates 30 and 40, and the upper substrate ( Lower electrodes 45 formed on the lower substrate 44 corresponding to positions of the upper electrodes 42 and the upper electrodes 42 formed on the upper substrates 30 and 40 between the pillars 30A and 40A of the 30 and 40. A load cell including the capacitors 33 and 47 including a) is prepared, and a load is applied on the upper substrates 30 and 40 of the load cell (S510).

Subsequently, the upper substrates 30 and 40 are deformed according to the applied load (S520). That is, the compression between the pillars 30A and 40A and the bending of the upper substrates 30 and 40 according to the load transmitted from the upper substrates 30 and 40 between the upper electrode 42 and the lower electrode 45 of the capacitor. The distance is reduced.

Subsequently, the capacitances of the capacitors 33 and 47 change as the distance between the upper electrode 42 and the lower electrode 45 changes (S530).

Next, the capacitance changes of the capacitors 33 and 47 are measured through the pads 34 and 46 (S540), and the load applied to the load cell is calculated (S550).

At this time, the capacitance changes of the capacitors 33 and 47 reflecting both the compression of the pillars 30A and 40A and the bending of the upper substrates 30 and 40 are measured. Therefore, when the same load is applied, the capacitance change of the capacitors 33 and 47 becomes larger than that of the conventional load cell. In other words, when the same load is applied, since the height change of the pillars 30A and 40A is larger than that of the conventional load cell, the load can be calculated in more precise units than in the prior art.

Although the technical spirit of the present invention has been specifically recorded in accordance with the above-described preferred embodiments, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

1 is a perspective view showing the structure of a load cell according to the prior art.

2A to 2D are cross-sectional views illustrating a manufacturing process of a load cell according to the prior art.

Figure 3 is a perspective view showing the structure of a load cell according to an embodiment of the present invention.

4A to 4F are cross-sectional views illustrating a manufacturing process of a load cell according to an embodiment of the present invention.

5 is a flowchart illustrating a procedure of a load measuring method using a capacitive load cell according to an embodiment of the present invention.

[Description of Symbols for Main Parts of Drawing]

30: upper substrate 30A: pillar

31: lower substrate 33: capacitor

34: Pad part

40: first substrate 40A: pillar

41: insulating film 42: upper electrode

43: dielectric film for capacitor 44: second substrate

45: lower electrode 46: pad portion

47: Capacitor

Claims (21)

An upper substrate including a plurality of pillars whose shape changes in accordance with the transmitted load; A lower substrate supporting the upper substrate; And A capacitor comprising an upper electrode formed on the upper substrate between the adjacent pillars and a lower electrode formed on the lower substrate corresponding to the position of the upper electrode. Capacitive load cell comprising a. The method of claim 1, The upper electrode, Electrically separated from the upper substrate by an insulating layer interposed between the upper substrate and the upper electrode. Capacitive load cell. The method of claim 1, The upper substrate is Grounded Capacitive load cell. The method of claim 1, The upper substrate is Under load through a flat top surface Capacitive load cell. The method of claim 4, wherein The capacitor, During load transfer, the capacitance changes according to the compression of the pillar and the degree of bending of the upper substrate. Capacitive load cell. The method of claim 1, The upper substrate is One side is cut a predetermined width to expose the pad portion of the lower substrate Capacitive load cell. The method of claim 1, A pad unit for measuring the capacitance of the capacitor formed on one side of the lower substrate Capacitive load cell further comprising. The method of claim 1, The pillar, Formed by etching a predetermined depth around the pillar predetermined area of the upper substrate Capacitive load cell. The method of claim 1, The lower substrate, And a groove formed by etching an area corresponding to the position of the upper electrode formed on the upper substrate, wherein the lower electrode is formed in the groove. Capacitive load cell. The method of claim 1, The capacitor, Deformation of the pillar according to the load applied to the upper substrate is formed in a large region Capacitive load cell. The method of claim 10, The capacitor, Is formed in the center of the capacitive load cell Capacitive load cell. The method of claim 1, The upper substrate is Made of silicone, The lower substrate, Made of silicone or glass Capacitive load cell. Forming an insulating film on the first substrate; Forming an upper electrode on the insulating layer between the pillar predetermined regions; Forming a dielectric film for a capacitor on the entire structure of the resultant product in which the upper electrode is formed; Forming a plurality of pillars by first etching the capacitor dielectric layer, the insulating layer, and the first substrate formed around the pillar predetermined region; Forming a groove by etching a second depth of a region of the second substrate corresponding to the position of the upper electrode formed on the first substrate; Forming a lower electrode in the groove; And Bonding the first substrate and the second substrate to form a capacitor between adjacent pillars; Capacitive load cell manufacturing method comprising a. The method of claim 13, Grounding the upper substrate Capacitive load cell manufacturing method further comprising. The method of claim 13, The capacitor, During load transfer, the capacitance changes according to the compression of the pillar and the degree of warpage of the first substrate. Method of manufacturing a capacitive load cell. The method of claim 13, The pillar forming step, When etching around the pillar predetermined area, the boundary area of the pad part is etched together, After the capacitor forming step, Cutting the etched boundary region to expose the pad portion of the second substrate; Capacitive load cell manufacturing method further comprising. The method of claim 13, The second depth has a value smaller than the first depth Method of manufacturing a capacitive load cell. The method of claim 17, The first depth is, 100 to 400 μm, The second depth, 1 to 3 μm Method of manufacturing a capacitive load cell. An upper substrate including a plurality of pillars whose shape changes in accordance with a transmitted load, a lower substrate supporting the upper substrate, and an upper electrode formed on the upper substrate between the pillars of the upper substrate and the upper electrode positions Applying a load to the upper substrate of the load cell including a capacitor including a lower electrode formed on the lower substrate; Changing the capacitance of the capacitor according to the compression of the pillar and the degree of bending of the upper substrate according to the load transmitted to the upper substrate; And Calculating a load applied to the upper substrate by reading a change in capacitance of the capacitor; Load measurement method using a capacitive load cell comprising a. The method of claim 19, The load cell, The upper substrate and the upper electrode are electrically separated by an insulating layer interposed between the upper substrate and the upper electrode. Load measurement method using a capacitive load cell. The method of claim 20, The load cell, The upper substrate is grounded Load measurement method using a capacitive load cell.

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