JP2021071442A - Measurement method for electric resistivity of thin film formed on metal substrate, and method for manufacturing electronic component and apparatus for manufacturing electronic component using the measurement method - Google Patents

Abstract

To provide a measurement method for electric resistivity of a thin film formed on a metal substrate.SOLUTION: The method includes steps of: (I) measuring current-voltage characteristics of a laminate comprising a metal substrate and a thin film formed on the metal substrate by use of a C-AFM; and (II) measuring current-voltage characteristics of a metal substrate of the same kind as the above metal substrate by use of a C-AFM. A contact resistance Rc_TF between the cantilever of the C-AFM and the laminate is obtained by the gradient of a current-voltage curve obtained in the step (I), a contact resistance Rc_m between the cantilever of the C-AFM and the metal substrate is obtained by a current-voltage curve obtained in step (II), and the electric resistivity of the thin film is calculated by the formula of ρTH=(ρa+ρm)Rc_TF/Rc_m-ρa, where ρa represents the electric resistivity of the cantilever of the C-AFM, ρm represents the electric resistivity of the metal substrate, and ρTH represents the electric resistivity of the thin film.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for measuring the electrical resistivity of a thin film formed on a metal substrate, a method for manufacturing an electronic component using the measuring method, and an apparatus for manufacturing an electronic component.

Thin films such as metal thin films and polymer thin films are used in various electronic components. The method for measuring the electrical resistance of a thin film is specified by ASTM and JIS standards, and is usually evaluated using an ohmmeter. For example, Non-Patent Document 1 reports that the electrical resistance of a graphene oxide film having a film thickness of 300 nm formed on a Si substrate by a spin coating method was measured using an ohmmeter. A micron-order thin film can be measured by the 4-terminal method, but a thinner thin film has a problem that it cannot be evaluated due to a short circuit when the conventional 4-terminal method is used. Therefore, a method for measuring the resistance of a thin film has been proposed. For example, Non-Patent Document 2 reports resistance measurement of carbon nanotubes on _{a SiO 2 substrate using a conductive atomic force microscope.}

The graphene film is a monatomic film composed of carbon atoms, and is in the limelight as a new material with high reliability because of its excellent electrical conductivity and chemical stability. For example, in Patent Document 1, graphene is introduced into the electronic traveling layer of the FET without using a p-channel FET (field effect transistor) or an n-channel FET, and the anbipolar characteristics of the graphene material are utilized to form CMOS. It is disclosed to realize an equivalent complementary type theoretical operation. Further, Patent Document 2 describes a step of forming a catalyst metal layer having a predetermined shape having a function of promoting graphene formation on a substrate main body as a method for easily producing a graphene material having a desired shape having electrode terminals that are difficult to peel off. A step of supplying a carbon source to the surface of the catalyst metal layer to grow graphene and a step of extracting the graphene from the catalyst metal layer as a graphene material are included. Before or after taking out as a material, an electrode terminal having a structure in which a Ti layer forming a base and a protective layer containing a metal as a main component selected from the group consisting of Mo, Ni, Ta and W are laminated in this order is formed. The method is disclosed. Further, Patent Document 3 describes graphene oxide or graphene oxide laminated on an ion conductor material layer having an ion conductor capable of conducting hydrogen ions or oxygen ions, a gate electrode layer sandwiching the ion conductor material layer, and an insulator substrate. An electrically conductive element having a graphene-based material layer having graphene and a drain electrode layer and a source electrode layer provided on the surface of the graphene-based material layer, between the layers thereof, or on the insulator substrate is disclosed.

WO2010 / 01944 Japanese Unexamined Patent Publication No. 2012-144419 WO2015 / 068651

Journal of Materials Chemistry C, 2019 Issue 9, pp.2583-2588 Science, 26 Apr 1996: Vol. 272, Issue 5261, pp. 523-526

A first object of the present invention is to provide a method for measuring the electrical resistivity of a thin film formed on a metal substrate. Further, it is a further subject to provide a manufacturing method of electronic parts and a manufacturing apparatus of electronic parts using the measurement method.

When the present inventors tried to measure the resistance of a thin film on a metal substrate such as a copper substrate by the four-terminal method, electricity flowed through the copper substrate and the measurement accuracy was poor. Therefore, the present inventors used a conductive interatomic force microscope. By measuring the current-voltage characteristics of a metal substrate and a laminate containing a thin film formed on the metal substrate and the current-voltage characteristics of a metal substrate of the same type as the metal substrate, and using a specific formula, the metal The present invention was completed with the idea of measuring the electrical resistance of a thin film formed on a substrate.

The present invention provides the following specific aspects and the like.
<1> A method for measuring the electrical resistivity of a thin film formed on a metal substrate.
(I) Using a conductive atomic force microscope to measure the current-voltage characteristics of the metal substrate and the laminate containing the thin film formed on the metal substrate, and (II) Using a conductive atomic force microscope. Including the step of measuring the current-voltage characteristics of a metal substrate of the same type as the metal substrate.
The contact resistance between the cantilever of the conductive atomic force microscope and the laminate containing the metal substrate and the thin film formed on the metal substrate, which is obtained from the slope of the current-voltage curve obtained in the step (I). Let R _{c_TF}
The contact resistance between the cantilever of the conductive atomic force microscope and the metal substrate obtained from the slope of the current-voltage curve obtained in the step (II) is R _{c_m} .
A method for measuring the electrical resistivity of a thin film formed on a metal substrate, which calculates the electrical resistivity of the thin film from the following formula (1).
ρ _TH = (ρ _a + ρ _m ) R _{c_TF} / R _{c_m −ρ a} equation (1)
(In the formula (1), ρ _a represents the electrical resistivity of the cantilever of the conductive atomic force microscope, ρ _m represents the electrical resistivity of the metal substrate, and ρ _TH represents the electrical resistivity of the thin film.)
<2> The method for measuring the electrical resistivity of a thin film formed on a metal substrate according to <1>, wherein the thickness of the thin film is 1 nm or more and 100 nm or less.
<3> The method for measuring the electrical resistivity of a thin film formed on a metal substrate according to <1> or <2>, wherein the thin film is made of graphene or graphene oxide.
<4> The electrical resistivity of the thin film formed on the metal substrate according to any one of <1> to <3>, wherein the metal substrate is selected from the group consisting of copper, iron, aluminum and alloys thereof. Measurement method.
<5> A method for manufacturing an electronic component including a metal substrate and a thin film formed on the metal substrate.
A step of preparing a metal substrate and a laminate containing a thin film formed on the metal substrate,
A step of preparing a metal substrate and a laminate containing a thin film formed on the metal substrate,
A step of measuring the electrical resistivity of the thin film formed on the metal substrate by the method for measuring the electrical resistivity of the thin film formed on the metal substrate according to any one of <1> to <4>, and the above-mentioned step. Judgment step of determining whether or not the electrical resistivity of the thin film measured by
Manufacturing methods for electronic components, including.
<6> The method for manufacturing an electronic component according to <5>, wherein the electronic component is a connector.
<7> A thin film forming section for forming a thin film on a metal substrate and a conductivity evaluation section for evaluating the conductivity of the thin film formed on the metal substrate are provided.
An apparatus for manufacturing electronic components, wherein the conductivity evaluation unit includes the following (A) to (C).
(A) An interatomic force microscope that measures the current-voltage characteristics of the metal substrate and the laminate containing the thin film formed on the metal substrate and the current-voltage characteristics of the same type of metal substrate as the metal substrate (B). Electrical resistivity calculation unit for calculating the electrical resistivity of the thin film from the following equation (1) ρ _TH = (ρ _a + ρ _m ) R _{c_TF} / R _{c_m −ρ a} equation (1)
In the formula (1), R _{c_TF} is obtained from the slope of the current-voltage curve of the current-voltage characteristic measurement result of the metal substrate and the laminate containing the thin film formed on the metal substrate by the atomic force microscope. , Contact resistance between the cantilever of the conductive atomic force microscope and the metal substrate and the laminate containing the thin film formed on the metal substrate; R _{c_m} is the same type of metal substrate as the metal substrate by the atomic force microscope. current - - the current measurement results voltage characteristics obtained from the slope of the voltage curve, the contact resistance between the Conductive AFM cantilever and the metal substrate; is [rho _a electrical cantilever of the Conductive AFM Resistance; ρ _m is the electrical resistance of the metal substrate; ρ _TH is the electrical resistance of the thin film.)
(C) Judgment unit <8> for determining whether or not the electrical resistivity of the thin film calculated by the electrical resistivity calculation unit (B) satisfies a predetermined reference value <8> The electronic component is a connector, <7 > The electronic component manufacturing apparatus described in.

According to the present invention, there is provided a method for measuring the electrical resistivity of a thin film formed on a metal substrate. Further, a method for manufacturing an electronic component and an apparatus for manufacturing an electronic component using the measurement method are provided.

FIG. 1 is a schematic diagram of contact current evaluation by a connected AFM. FIG. 2 is a diagram showing a measurement site of the Conducive AFM of Example 1. FIG. 3 is a diagram showing an IV curve of the copper substrate portion of Example 1. FIG. 4 is a diagram showing an IV curve of the graphene oxide film (thin film portion) of Example 1.

Hereinafter, an example of a preferred embodiment of the present invention will be described. However, the following embodiments are merely examples. The present invention is not limited to the following embodiments.

1. 1. Method for Measuring Electrical Resistance of a Thin Film Formed on a Metal Substrate In one embodiment of the present invention, (I) a laminate containing the metal substrate and a thin film formed on the metal substrate using a conductive interatomic force microscope. The step (I) includes the step of measuring the current-voltage characteristic of the body and (II) the step of measuring the current-voltage characteristic of the same type of metal substrate as the metal substrate using a conductive interatomic force microscope. The contact resistance between the cantilever of the conductive interatomic force microscope and the laminate containing the metal substrate and the thin film formed on the metal substrate, which is obtained from the slope of the current-voltage curve obtained in the above, is _{defined as R c_TF.} The contact resistance between the cantilever of the conductive interatomic force microscope and the metal substrate obtained from the slope of the current-voltage curve obtained in step (II) is R _{c_m,} and the electrical resistance of the thin film is calculated from the following equation (1). It is characterized by calculating the rate.
ρ _TH = (ρ _a + ρ _m ) R _{c_TF} / R _{c_m −ρ a} equation (1)
(In the formula (1), ρ _a represents the electrical resistivity of the cantilever of the conductive atomic force microscope, ρ _m represents the electrical resistivity of the metal substrate, and ρ _TH represents the electrical resistivity of the thin film.)

R c_m and R _{c_TH} are represented by the following equations (2) and (3), respectively, according to the Holm equation for _{obtaining the contact resistance.} In the formula, ρ _a is the electrical resistivity of the cantilever of the _{conductive atomic force microscope used for the measurement, ρ m} is the electrical resistivity of the metal substrate, and ρ _TH is the electrical resistivity of the thin film. a corresponds to the contact area projected circle radius.
R _{c_m} = (ρ _a + ρ _m ) / 4a ₁ equation (2)
R _{c_TH} = (ρ _a + ρ _TH ) / 4a ₂ equation (3)
Since the tip radius of the cantilever probe of the conductive atomic force microscope is as sharp as 100 to 200 nm, the portion where the tip of the probe contacts the measurement sample is the true contact area. When the thickness of the thin film 100nm thinner than the case of applying the same load at the same cantilever, a ₁ and a ₂ in formula (3) in the formula (2) can be assumed to be approximately the same. Therefore, the electrical resistivity of the thin film on the metal substrate can be calculated from the equations (2) and (3) by the following equation (1).
ρ _TH = (ρ _a + ρ _m ) R _{c_TF} / R _{c_m −ρ a} equation (1)

(I) Step of measuring the current-voltage characteristics of the metal substrate and the laminate containing the thin film formed on the metal substrate using a conductive atomic force microscope Fig. 1 shows a schematic diagram of contact current evaluation by Conducive AFM. Shown. In addition, FIG. 2 shows the measurement site of the Conducive AFM of Example 1 described later. As shown in FIGS. 1 and 2, a conductive atomic force microscope is used to measure the current-voltage characteristics of the metal substrate and the laminate including the thin film formed on the metal substrate. In FIG. 1, 101 represents a measurement sample in which a thin film is formed on a metal substrate, 102 represents a cantilever of a conductive atomic force microscope, and 103 represents a sample table of a conductive atomic force microscope. In FIG. 2, 201a represents a graphene oxide film (thin film), 201b represents a copper substrate (metal substrate), and 202 represents a cantilever of a conductive atomic force microscope. Commercially available products can be used as the conductive atomic force microscope, and examples thereof include Park NX10 manufactured by Park Systems Co., Ltd. and AFM5500M manufactured by Hitachi High-Technologies Corporation. Commercially available cantilever can be used, and examples thereof include those made of Pt, Rh, Au or conductive diamond-coated Si. From the inclination of the current-voltage curve of the metal substrate and the laminate containing the thin film formed on the metal substrate, which was measured using a conductive atomic force microscope, the cantilever of the conductive atomic force microscope, the metal substrate, and the metal substrate. Contact resistance with a laminate containing a thin film formed on a metal substrate can be obtained. In the present specification, the cantilever of the conductive atomic force microscope obtained from the slope of the current-voltage curve obtained in step (I), the metal substrate, and the laminate containing the thin film formed on the metal substrate. _{Let R c_TF be} the contact resistance of.

(II) Step of measuring the current-voltage characteristics of the same type of metal substrate as the metal substrate using a conductive atomic force microscope As shown in Fig. 2, the same type as the metal substrate using a conductive atomic force microscope. Measure the current-voltage characteristics of the metal substrate of. In this step, it is sufficient if the current-voltage characteristics of the metal substrate on which the thin film is formed can be measured, and the "metal substrate of the same type as the metal substrate" is another metal substrate of the same type as the metal substrate on which the thin film is formed. It may be a metal substrate itself on which a thin film is formed. A commercially available product can be used as the atomic force microscope, and "(I) a conductive interatomic force microscope is used to measure the current-voltage characteristics of the metal substrate and the laminate including the thin film formed on the metal substrate. The same as those exemplified in the section "Steps to be performed" is preferably used. From the viewpoint of cost, it is preferable to use the same atomic force microscope as the atomic force microscope used in the step (I) as the atomic force microscope used in the step (II). The contact resistance between the cantilever of the conductive atomic force microscope and the metal substrate can be obtained from the inclination of the current-voltage curve of the same type of metal substrate as the metal substrate measured using the conductive atomic force microscope. In the present specification, the contact resistance between the cantilever of the conductive atomic force microscope and the metal substrate obtained from the slope of the current-voltage curve obtained in step (II) is _defined as R c_m.

(Thin film)
The material and thickness constituting the thin film can be appropriately selected according to the purpose.
In one embodiment of the present invention, the thickness of the thin film is preferably 1 nm or more and 100 nm or less, and more preferably 1 nm or more and 30 nm or less. The electrical resistivity of a thin film having a thickness in this range can be suitably measured by using the measuring method of the present invention.
Further, in one embodiment of the present invention, the thin film is preferably composed of graphene, graphene oxide (GO), Au or Ag, and more preferably graphene or graphene oxide from the viewpoint of conductivity. Electrical connection members such as connectors are required to have high contact reliability with the mating terminal and high wear resistance at the connecting portion with the mating terminal. Therefore, the contact portion of the connector is generally plated with a precious metal made of a precious metal such as gold, silver or tin. However, if expensive precious metal plating is used, the production cost of the connector tends to be high. By using a thin film made of graphene or graphene oxide for the electrical connection member, the cost can be suppressed as compared with the use of a precious metal. Since the silicon substrate is insulating, graphene oxide cannot be formed on the silicon substrate by the electrophoretic deposition method (EPD). With such a thin film that cannot be formed on a silicon substrate, the electrical resistivity cannot be measured on the silicon substrate as in the method of Non-Patent Document 1. Further, even if an attempt is made to measure the electrical resistivity of a nanometer-order thin film of a material that cannot be formed on a silicon substrate on a metal substrate, the current flows preferentially through the metal substrate, so that the measurement cannot be performed accurately. .. According to the measuring method of the present embodiment, it is possible to measure the electrical resistivity of a thin film of a material that cannot be measured on a metal substrate by the conventional method and cannot be formed on a silicon substrate.

(Metal substrate)
The type and size of the metal substrate can be appropriately selected according to the purpose.
In one embodiment of the present invention, the metal substrate is preferably selected from the group consisting of copper, iron, aluminum and alloys thereof from the viewpoint of cost. Copper is preferably used when it is used as a terminal base material for a connector, and aluminum and an aluminum alloy are preferably used when it is used as an electrode.

2. Method for Manufacturing Electronic Components The measuring method of the present invention is for measuring the electric resistance of a metal substrate and a thin film of a laminate including a thin film formed on the metal substrate without separating the thin film and the metal substrate. Based on the measurement results, the laminated body can be processed as it is. Therefore, by setting the method for measuring the electrical resistivity of the thin film formed on the metal substrate as one step of manufacturing electronic components, it is possible to efficiently manufacture electronic components. That is, a method for manufacturing an electronic component including a metal substrate and a thin film formed on the metal substrate, wherein a laminate containing the metal substrate and the thin film formed on the metal substrate is prepared. The step of measuring the electric resistance of the thin film formed on the metal substrate by the measuring method described in "Method of measuring the electric resistance of the thin film formed on the metal substrate", and the electricity of the thin film measured by the step. An aspect of the present invention is also a method for manufacturing an electronic component including a metal substrate and a thin film formed on the metal substrate, which includes a determination step of determining whether or not the resistance rate satisfies a predetermined reference value.

(Step of preparing a metal substrate and a laminate containing a thin film formed on the metal substrate)
The metal substrate and the laminate containing the thin film formed on the metal substrate may be a commercially available product, or may be produced by carrying out a step of forming a thin film on the metal substrate by a known method. .. As for the "metal substrate" and the "thin film", the description in the section "1. Method for measuring the electrical resistivity of the thin film formed on the metal substrate" is applied.
The method for forming the thin film on the metal substrate is not particularly limited, and may be appropriately selected depending on the type and thickness of the thin film. For example, known thin film forming means such as electrophoretic deposition (EPD), sol-gel method, spin coating, dip coating, knife coating, vapor deposition, sputtering, reactive sputtering, ion beam sputtering, and CVD can be used. Above all, when the thin film is made of graphene or graphene oxide, the EPD method is preferable from the viewpoint of cost. Graphene oxide, which is obtained by oxidizing graphene, is synthesized by chemically oxidizing graphite, which is inexpensive and available in large quantities. Since graphene oxide has a polar group such as a carboxyl group or a hydroxyl group, it exhibits dispersibility in a polar solvent such as water and is charged in the polar solvent. Therefore, when a metal substrate is charged into the polar solvent and a voltage is applied to the metal substrate, it can be deposited on a substrate having a charge opposite to that of graphene oxide.

(Step of measuring the electrical resistivity of a thin film formed on a metal substrate)
The description in the section "1. Method for measuring the electrical resistivity of a thin film formed on a metal substrate" is applied to this step.

(Determination of determining whether or not the electrical resistivity of the thin film measured in the above step satisfies a predetermined reference value) Step In this step, an appropriate material for electronic parts is selected. The predetermined reference value is set by the electronic component, and may be set according to various standards. For example, in the case of a connector, it can be 0.05 Ω · cm or less, and in the case of a switch, it can be 0.1 Ω · cm or less.
In the present embodiment, the steps other than the above steps are not particularly limited, and a normal manufacturing process may be carried out according to the electronic component for manufacturing purposes.
In the present embodiment, the electronic components preferably include connectors, switches and the like.
According to the method for manufacturing electronic components of the present embodiment, the electrical resistivity of a thin film, which could not be measured on a metal substrate in the past, can be measured in a state of being formed on the metal substrate without separating the thin film and the metal substrate. , Only the laminate determined to satisfy a predetermined reference value can be used as it is as a material for electronic components. Therefore, the inspection process after the completion of the electronic component can be simplified, the disposal of the electronic component can be avoided, and the entire electronic component manufacturing process can be simplified and the cost can be suppressed.

3. 3. Electronic component manufacturing device An electronic component manufacturing device that includes a thin film forming unit that forms a thin film on a metal substrate and a conductivity evaluation unit that evaluates the conductivity of the thin film formed on the metal substrate. An apparatus for manufacturing an electronic component whose evaluation unit includes the following (A) to (C) is also an aspect of the present invention.
(A) An interatomic force microscope that measures the current-voltage characteristics of the metal substrate and the laminate containing the thin film formed on the metal substrate and the current-voltage characteristics of the same type of metal substrate as the metal substrate (B). Electrical resistivity calculation unit for calculating the electrical resistivity of the thin film from the following equation (1) ρ _TH = (ρ _a + ρ _m ) R _{c_TF} / R _{c_m −ρ a} equation (1)
In the formula (1), R _{c_TF} is obtained from the slope of the current-voltage curve of the current-voltage characteristic measurement result of the metal substrate and the laminate containing the thin film formed on the metal substrate by the atomic force microscope. , Contact resistance between the cantilever of the conductive atomic force microscope and the thin film; R _{c_m} is the current-voltage curve of the measurement result of the current-voltage characteristics of the same type of metal substrate as the metal substrate by the atomic force microscope. The contact resistance between the cantilever of the conductive atomic force microscope and the metal substrate obtained from the inclination; ρ _a is the electrical resistance of the cantilever of the conductive atomic force microscope; ρ _m is the electrical resistance of the metal substrate; ρ _TH represents the electrical resistance of the thin film.)
(C) A determination unit for determining whether or not the electrical resistivity of the thin film calculated by the electrical resistivity calculation unit (B) satisfies a predetermined reference value.

(Thin film forming part)
In the thin film forming portion where the thin film is formed on the metal substrate, a step of forming the thin film on the metal substrate is carried out.
The step of forming the thin film on the metal substrate may be selected according to the target thin film, and includes the "metal substrate and the thin film formed on the metal substrate" in the section "2. Manufacturing method of electronic components". The description of "the process of preparing the laminate" applies. For example, when the electrophoretic deposition method (EPD) is used, the thin film forming portion may be formed by combining a reaction vessel and an electrode depending on the type of thin film. Further, a commercially available spin coater, dip coater, knife coater, vapor deposition apparatus, ion beam sputtering apparatus, CVD apparatus, PVD apparatus and the like may be used.

(Conductivity evaluation unit)
The conductivity evaluation unit performs a step of evaluating the conductivity of the thin film formed on the metal substrate. The conductivity evaluation unit includes the following (A) to (C).
(A) An interatomic force microscope that measures the current-voltage characteristics of the metal substrate and the laminate containing the thin film formed on the metal substrate and the current-voltage characteristics of the same type of metal substrate as the metal substrate (B). Electrical resistivity calculation unit for calculating the electrical resistivity of the thin film from the following equation (1) ρ _TH = (ρ _a + ρ _m ) R _{c_TF} / R _{c_m −ρ a} equation (1)
In the formula (1), R _{c_TF} is obtained from the slope of the current-voltage curve of the current-voltage characteristic measurement result of the metal substrate and the laminate containing the thin film formed on the metal substrate by the atomic force microscope. , Contact resistance between the cantilever of the conductive atomic force microscope and the thin film; R _{c_m} is the current-voltage curve of the measurement result of the current-voltage characteristics of the same type of metal substrate as the metal substrate by the atomic force microscope. The contact resistance between the cantilever of the conductive atomic force microscope and the metal substrate obtained from the inclination; ρ _a is the electrical resistance of the cantilever of the conductive atomic force microscope; ρ _m is the electrical resistance of the metal substrate; ρ _TH represents the electrical resistance of the thin film.)
(C) A determination unit for determining whether or not the electrical resistivity of the thin film calculated by the electrical resistivity calculation unit (B) satisfies a predetermined reference value. (A) Formed on the metal substrate and the metal substrate. As an interatomic force microscope for measuring the current-voltage characteristics of the laminate containing the thin film and the current-voltage characteristics of a metal substrate of the same type as the metal substrate, a commercially available product can be used. The description in the section "Method of measuring the electrical resistivity of the thin film formed in" applies. The electrical resistivity calculation unit (B) is not particularly limited as long as the "step of measuring the electrical resistivity of the thin film formed on the metal substrate" described in the section "2. Manufacturing method of electronic components" can be performed. For example, an apparatus that performs processing based on a program set to obtain the electrical resistivity of the thin film based on the equation (1) can be connected to an electron inter-force microscope. Further, the determination unit (C) is not particularly limited as long as the determination step of determining whether or not the electrical resistivity of the thin film satisfies a predetermined reference value can be performed, and the electrical resistivity calculation unit sets the reference value in advance. It is also possible to combine the determination unit so that the determination process is performed by the program, or the device that performs the determination process by the program in which the reference value is set in advance may be connected to the electrical resistivity calculation unit to perform the determination process.

In the present embodiment, the parts other than the thin film forming part and the conductivity evaluation part are not particularly limited, and a normal unit may be provided according to the electronic component for manufacturing purposes.
In the present embodiment, the electronic components preferably include connectors, switches and the like.
According to the electronic component manufacturing apparatus of the present embodiment, the electric resistance of a thin film, which could not be measured on a metal substrate in the past, can be measured in a state of being formed on the metal substrate without separating the thin film and the metal substrate. When it is evaluated and it is determined that the predetermined reference value is satisfied, it is used as it is as a material for electronic components, so that the entire electronic component manufacturing process is simplified and the cost is suppressed.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention can be appropriately modified as long as the gist of the present invention is not deviated. Therefore, the scope of the present invention should not be construed as limited by the specific examples shown below.

[Example 1]
Graphene oxide (GO) was formed on a copper substrate by the EPD method. The film forming conditions are shown in Table 1. GO was formed on half of the substrate to measure the film thickness. Conductive Atomic Force Microscope (Con)
A topographic image was obtained using a ductive AFM) and the film thickness was measured and found to be about 4 nm. Using Conducive AFM (NX10 manufactured by Park Systems, diamond-coated Si cantilever CDT-NCLR, measurement condition: load 980 nN), measure the IV characteristics of the copper substrate and the laminate in which the GO film is formed on the copper substrate, respectively. did.
FIG. 3 shows the IV curve of the copper substrate portion, and FIG. 4 shows the IV curve of the GO film portion (laminated body). From the slope of the obtained IV curve, the contact resistance C between the cantilever and the Cu substrate and the contact resistance R _{c_GO} between the cantilever and the laminate in which the GO film was formed on the copper substrate were calculated.
From FIG. 3, R _{c_cu} is 21.84 kΩ. From FIG. 4, R _{c_GO} is 207.94 kΩ. Since the cantilever was coated with diamond, the ρ _cantilever was 0.005 Ω · cm. The electrical resistivity of copper ρ _Cu was 1.7 × 10 ^-6 Ω · cm. The electrical resistivity of GO calculated by substituting the above value into the equation (1) was ρ _GO = 0.043Ω · cm.

When the method for measuring the electrical resistivity of a thin film formed on a metal substrate of the present invention is used, the electrical resistivity of a thin film conventionally measured on an insulating substrate can be measured in a state of being formed on the metal substrate. Can be done. In the method for measuring the electrical resistance of a thin film formed on a metal substrate of the present invention, measurement can be performed in a simple process without separating the thin film and the metal substrate, and the measurement target is electronically measured as it is based on the measurement result. It can be used for parts, can be introduced as a process of manufacturing electronic parts, and the cost can be suppressed, so it has great industrial utility value.

101 Measurement sample 102 Cantilever of conductive atomic force microscope 103 Sample stand 201a Graphene oxide film 201b Copper substrate 202 Cantilever of conductive atomic force microscope

Claims (8)

A method for measuring the electrical resistivity of a thin film formed on a metal substrate.
(I) Using a conductive atomic force microscope to measure the current-voltage characteristics of the metal substrate and the laminate containing the thin film formed on the metal substrate, and (II) Using a conductive atomic force microscope. Including the step of measuring the current-voltage characteristics of a metal substrate of the same type as the metal substrate.
The contact resistance between the cantilever of the conductive atomic force microscope and the laminate containing the metal substrate and the thin film formed on the metal substrate, which is obtained from the slope of the current-voltage curve obtained in the step (I). Let R _{c_TF}
The contact resistance between the cantilever of the conductive atomic force microscope and the metal substrate obtained from the slope of the current-voltage curve obtained in the step (II) is R _{c_m} .
A method for measuring the electrical resistivity of a thin film formed on a metal substrate, which calculates the electrical resistivity of the thin film from the following formula (1).
ρ _TH = (ρ _a + ρ _m ) R _{c_TF} / R _{c_m −ρ a} equation (1)
(In the formula (1), ρ _a represents the electrical resistivity of the cantilever of the conductive atomic force microscope, ρ _m represents the electrical resistivity of the metal substrate, and ρ _TH represents the electrical resistivity of the thin film.) The method for measuring the electrical resistivity of a thin film formed on a metal substrate according to claim 1, wherein the thickness of the thin film is 1 nm or more and 100 nm or less. The method for measuring the electrical resistivity of a thin film formed on a metal substrate according to claim 1 or 2, wherein the thin film is made of graphene or graphene oxide. The method for measuring the electrical resistivity of a thin film formed on a metal substrate according to any one of claims 1 to 3, wherein the metal substrate is selected from the group consisting of copper, iron, aluminum and alloys thereof. .. A method for manufacturing an electronic component including a metal substrate and a thin film formed on the metal substrate, wherein a laminate containing the metal substrate and the thin film formed on the metal substrate is prepared.
A step of preparing a metal substrate and a laminate containing a thin film formed on the metal substrate,
A step of measuring the electrical resistivity of a thin film formed on the metal substrate by the method for measuring the electrical resistivity of a thin film formed on the metal substrate according to any one of claims 1 to 4, and the step of measuring the electrical resistivity of the thin film formed on the metal substrate. Judgment step of determining whether or not the electrical resistivity of the thin film measured by
Manufacturing methods for electronic components, including. The method for manufacturing an electronic component according to claim 5, wherein the electronic component is a connector. A thin film forming section for forming a thin film on a metal substrate and a conductivity evaluation section for evaluating the conductivity of the thin film formed on the metal substrate are provided.
An apparatus for manufacturing electronic components, wherein the conductivity evaluation unit includes the following (A) to (C).
(A) An interatomic force microscope that measures the current-voltage characteristics of the metal substrate and the laminate containing the thin film formed on the metal substrate and the current-voltage characteristics of the same type of metal substrate as the metal substrate (B). Electrical resistivity calculation unit for calculating the electrical resistivity of the thin film from the following equation (1) ρ _TH = (ρ _a + ρ _m ) R _{c_TF} / R _{c_m −ρ a} equation (1)
In the formula (1), R _{c_TF} is obtained from the slope of the current-voltage curve of the current-voltage characteristic measurement result of the metal substrate and the laminate containing the thin film formed on the metal substrate by the atomic force microscope. , Contact resistance between the cantilever of the conductive atomic force microscope and the metal substrate and the laminate containing the thin film formed on the metal substrate; R _{c_m} is the same type of metal substrate as the metal substrate by the atomic force microscope. current - - the current measurement results voltage characteristics obtained from the slope of the voltage curve, the contact resistance between the Conductive AFM cantilever and the metal substrate; is [rho _a electrical cantilever of the Conductive AFM Resistance; ρ _m is the electrical resistance of the metal substrate; ρ _TH is the electrical resistance of the thin film.)
(C) A determination unit for determining whether or not the electrical resistivity of the thin film calculated by the electrical resistivity calculation unit (B) satisfies a predetermined reference value. The electronic component manufacturing apparatus according to claim 7, wherein the electronic component is a connector.

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