JP2000178522A - Method of evaluating curing degree in anisotropic conductive adhesive and connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the quantitative determination in the evaluation method for the curing degree in an anisotropic conductive adhesive and to enable the evaluation of fluctuation of the curing degree in the connected sites and to provide a connection structure with reduced fluctuation of the curing degree. SOLUTION: In this evaluation method for the curing degree of an epoxy resin which uses a Raman spectrum, by utilizing a peak of the epoxy group (a Raman shift value of 2,990 cm-1 to 3,025 cm-1) which is good in the separation from other peaks, the curing degree of an anisotropic conductive adhesive is evaluated with improved quantitative determination. Further, the curing degree of fine sites of 1-100 μm are evaluated by effecting the Raman spectrum measurement under a microscope.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a liquid crystal panel or the like which is formed between electrodes of two circuit boards and is heated and pressed to bond the two circuit boards and to electrically connect the two electrodes. The present invention relates to a method for evaluating the degree of curing after bonding in an anisotropic conductive adhesive and a connection structure.

[0002]

2. Description of the Related Art As a method of evaluating the degree of curing of an anisotropic conductive adhesive containing an epoxy resin, a curing agent, and conductive particles, various analytical methods for analyzing the degree of curing of an epoxy resin can be considered. As these analytical methods, a DSC method (thermal analysis, edited by Kotaro Kotaro, P260-P262, Kodansha) which evaluates from a calorific value measured using a DSC (differential scanning calorimeter), a method using a nuclear magnetic resonance spectrum (Shinbo) Masaki Edition, Epoxy Resin Handbook, P248-P249, Nikkan Kogyo Shimbun), Analytical Method Using Infrared Absorption Spectra, etc. (Shinbo Masaki Edition, Epoxy Resin Handbook, P251-P25)
3, Nikkan Kogyo Shimbun and Yukihiro Ozaki, New Industrial Spectroscopic Measurement Technology, P265-267, IPC Publishing). Furthermore, as a method for analyzing the degree of curing of an epoxy resin using Raman spectrum, a method utilizing the decrease in the peak intensity of the epoxy group at 1260 cm- ¹ (Bunseki, 1996, 618 (1996), etc.) is known. .

However, when evaluating the degree of curing of the anisotropic conductive adhesive after bonding using the DSC method, it is necessary to collect a sample from between the electrodes of the bonded circuit board, and the amount of the sample must be reduced. Since it usually requires 10 mg or more, it is insufficient as a practical method for evaluating the degree of curing. Furthermore, in the DSC method, there is a problem that it is not possible to evaluate a variation in the degree of curing at the connection part because a minute part cannot be measured.
Further, when an attempt is made to utilize a nuclear magnetic resonance spectrum, the anisotropic conductive adhesive after bonding is insoluble and infusible and cannot be formed into a solution, so that it cannot be applied. In the method using the infrared absorption spectrum, it is necessary to adjust the sample thickness,
An anisotropic conductive adhesive between bonded electrodes or on an electrode peeled off after bonding is not applicable because the electrodes and the like do not transmit or reflect infrared light. Furthermore, there is a problem that the quantitativeness is low. On the other hand, the analysis method using Raman spectrum measures scattered light, so it can be measured even with an anisotropic conductive adhesive on the electrode.However, the method using the decrease in the peak intensity of the epoxy group at 1260 cm- ¹ is quantitative. It was insufficient as a practical method for evaluating the degree of hardening due to low properties.

[0003]

In the case where the electrodes of the two circuit boards are bonded and the two electrodes are electrically connected by using an anisotropic conductive adhesive, the anisotropic conductive adhesive after bonding is used. The curing degree of the adhesive is a very important factor for the adhesive strength, connection reliability, and the like. However, as described above, the method for evaluating the degree of curing of the anisotropic conductive adhesive after bonding according to the conventional technique is not practically sufficient, and the degree of curing of the anisotropic conductive adhesive after bonding on the electrode is not sufficient. Practical evaluation methods are required. Furthermore, there is a need for a practical method for evaluating the degree of cure of an anisotropic conductive adhesive that can evaluate the variation in degree of cure at the connection portion of the circuit board. In addition, with the conventional method of evaluating the degree of curing, it is difficult to provide a connection structure using an anisotropic conductive adhesive, which has been confirmed that both the connection center and the connection end of the connection have been sufficiently cured. Met. The present invention has been made in view of the above circumstances, and provides a practical method for evaluating the degree of curing of an anisotropic conductive adhesive and a connection structure.

[0004]

Means for Solving the Problems According to the present invention, as a result of intensive studies on a method of analyzing the degree of curing of an epoxy resin, the peak intensity of the epoxy group, which is different from that of the conventional method, is used in the Raman spectrum to obtain the degree of curing. It has been found that the quantitativeness can be improved to a practical level and the above object can be achieved, and based on this finding, the present invention has been completed.

That is, the present invention relates to an anisotropic conductive adhesive containing an epoxy resin, a curing agent and conductive particles.
Raman shift value 2990cm- ¹ in the Raman spectrum
The present invention relates to a method for evaluating the degree of curing of the anisotropic conductive adhesive and a connection structure, wherein the degree of curing is evaluated by using the peak intensity of the epoxy group within the range of 3025 cm- ¹ or less.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The Raman spectrum of the anisotropic conductive adhesive used in the present invention is not particularly limited as long as it uses a Raman spectrum measured by a Raman spectrometer excited by visible laser, a Raman spectrometer excited by near-infrared laser, or the like. However, it is more preferable to use a Raman spectrometer excited by near-infrared laser because interference with the Raman spectrum due to fluorescence can be reduced. In the present invention, a peak intensity of an epoxy group having a Raman shift value in the range of 2990 cm- ¹ or more and 3025 cm- ¹ or less in the Raman spectrum is used to evaluate the degree of curing. The peak intensity used at this time is a Raman shift value of 2990 cm- ^1.
More 3025Cm- ¹ be the maximum value within the range, it may be a peak area intensity for the wave number region in the Raman shift value 2990Cm- ¹ or 3025Cm- ¹ or less. The Raman shift value 2990Cm- ¹ or 3025Cm- ¹ and the following wave number region in the range, but the present invention is fixed to the Raman shift value 2990Cm- ¹ or 3025Cm- ¹ the range, the width of the frequency domain may optionally Can be taken. However, when utilizing the peak area intensity, it is indispensable that an arbitrary wave number region falls within a range of a Raman shift value of 2990 cm- ¹ or more and 3025 cm- ¹ or less. When the peak intensity in the region where the Raman shift value is less than 2990 cm- ¹ and / or exceeds 3025 cm- ¹ is used, the quantitativeness of the degree of curing is reduced due to the influence of peaks other than epoxy groups, which is practically insufficient. .

[0007] Among the methods for evaluating the degree of cure by using the peak of the epoxy group within the Raman shift value of 2990 cm- ¹ or more and 3025 cm- ¹ or less in the Raman spectrum,
Raman Raman shift value 2990Cm- ¹ or 3025Cm- ¹ or less epoxy groups within the scope of the peak (A) and the Raman shift value 3025Cm- ¹ or 3150cm- aromatic ring peak at ¹ within the range (B) The method of evaluating the degree of cure from the intensity ratio (IA / IB) is based on the fact that the peak (B) of the aromatic ring, which is the reference peak, exists in the wavenumber region near the peak (A) of the epoxy group, Since the influence of line fluctuation is small, the quantitative property is good and the Raman intensity ratio (IA
/ IB) is particularly preferable in practical use because it can be easily obtained.

The Raman spectrum of the anisotropic conductive adhesive used in the present invention is measured under a microscope (ie,
The measurement is performed by microscopic Raman spectroscopy), and the measurement diameter is set to a minute portion of 1 μm or more and 100 μm or less, so that it is possible to evaluate the minute portion at a specific position of the connection portion on the bonded circuit board, and to perform more detailed It is further preferable because it is a practical method for evaluating the degree of curing of the anisotropic conductive adhesive.

In a connection structure made of an anisotropic conductive adhesive containing an epoxy resin, a curing agent and conductive particles, the connection structure is evaluated by the method for evaluating the degree of curing using the Raman spectrum measured by the microscopic Raman spectroscopy. Among the connection structures, the degree of cure (X) measured at a position within a radius of 100 μm from the center of the connection structure and the degree of cure (Y) measured at a position within a radius of 100 μm from the end of the connection structure And the ratio (Y
/ X) is not less than 0.8 and not more than 1.2, and the connection structure having both the curing degree (X) and the curing degree (Y) of 70% or more has a high adhesive strength and a high connection reliability. It was good. The end of the connection structure refers to an arbitrary portion existing in a region of less than 200 μm inside the outer periphery of the connection structure. Further, the central portion of the connection structure refers to an arbitrary portion existing 200 μm or more inside the outer periphery of the connection structure. On the other hand, when the ratio (Y / X) of the degree of cure is less than 0.8 or exceeds 1.2, partial peeling occurs, and when the degree of cure (Y) is less than 70%, Insufficient adhesion.

The anisotropic conductive adhesive to which the present invention is applied essentially contains an epoxy resin, a curing agent and conductive particles. In addition to these components, for example, a tackifier or Adhesive modifiers such as plasticizers, surfactants, film-forming materials, acrylic resins, fillers such as silica, crosslinking agents such as isocyanate and melamine, solvents, polymerization inhibitors, metal deactivators, coupling agents, etc. Can be contained as needed. The form of the anisotropic conductive adhesive may be, for example, a film, a sheet, a paste, or the like,
There is no particular limitation. Examples of applicable anisotropic conductive adhesives include, for example, Anisorm AC-7201, AC-2052
(Both trade names of Hitachi Chemical Co., Ltd.) and the like, but are not particularly limited thereto.

The epoxy resin contained in the anisotropic conductive adhesive is, for example, a bisphenol type epoxy resin derived from epichlorohydrin and bisphenol A or bisphenol F, or an epoxy resin derived from epichlorohydrin and phenol novolak or cresol novolak. A novolak resin is typical, and various epoxy resins having two or more oxirane groups in one molecule such as glycidyl ether, glycidylamine, glycidyl ester, alicyclic and heterocyclic can be applied. These can be used alone or as a mixture of two or more.

Examples of the curing agent contained in the anisotropic conductive adhesive include aliphatic amines, aromatic amines, carboxylic anhydrides, thiols, alcohols, phenols, isocyanates, tertiary amines, boron complex salts, and the like. Various systems such as inorganic acids, hydrazides and imidazoles and modified products thereof can be applied. These can be used alone or as a mixture of two or more.

The conductive particles contained in the anisotropic conductive adhesive include metal particles such as Ni, Cr, Co, and the like.
Al, Sb, Mo, Pb, Cu, Ag, Pt, Au, S
n, Ta and the like, and non-conductive materials such as glass, ceramics and plastics particles coated with these metals may be used. These can be used as simple substances, alloys, composites and mixtures.

[0010] Evaluation method of the curing level of the anisotropic conductive adhesive of the present invention, by utilizing a peak intensity of epoxy groups in the Raman shift value 2990Cm- ¹ or 3025Cm- ¹ within the following ranges in the Raman spectrum, This is a method for evaluating the degree of curing of a practical anisotropic conductive adhesive, which can improve quantitativeness compared to the conventional method using the peak of an epoxy group having a Raman shift value of 1260 cm- ¹ . Compared to the conventional method using the peak of the epoxy group at 1260 cm- ¹ , the quantitative property was improved because the peak of the epoxy group within the range of 2990 cm- ¹ or more and 3025 cm- ¹ or less It is probable that the interference from the peaks of other functional groups and the like could be reduced as much as possible because of good separation from the peak. As a result, the quantitativeness of the method for evaluating the degree of cure of epoxy resin using Raman spectrum was able to be set to a practical level for the first time, and the practical evaluation of the degree of cure of anisotropic conductive adhesive became possible. It has become. In addition, by using micro Raman spectroscopy in combination with the method of evaluating the degree of curing of the anisotropic conductive adhesive, it has become possible to evaluate the degree of curing in minute parts, which has been difficult so far. In a connection structure made of a one-sided conductive adhesive, a connection structure in which a central portion and an end portion are sufficiently cured can be provided.

[0011]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples. (Example 1) (1) Anisotropic conductive adhesive Anisotropic conductive adhesive includes a commercially available anisotropic conductive film Anisormu AC-2052 (trade name, manufactured by Hitachi Chemical Co., Ltd., thickness 35 μm, film width 3). .0 mm) and heat-cured under the conditions shown in Table 1 to produce anisotropic conductive adhesives having various degrees of curing (Table 1 Samples Nos. 1 to 5).
In addition, Anisorm AC-2052 (trade name, manufactured by Hitachi Chemical Co., Ltd., thickness 35 μm, film width 3.0 mm)
With a line width of 100 μm, a pitch of 200 μm, and a thickness of 35
Flexible circuit board (FPC) having a copper circuit of μm and a thin layer of indium oxide (ITO) on the entire surface.
A 1 mm glass plate was bonded by using a heating / pressing head having a head width of 2 mm by heating / pressing at 170 ° C.-2 MPa for 20 seconds under connection conditions. At this time, after bonding the adhesive surface of the anisotropic conductive adhesive on the FPC in advance, the temperature is 80 ° C.-1 MPa-
Temporary connection was performed for 5 seconds, and then the separator (tetrafluoroethylene film) was peeled off and bonded to ITO. Thereby, an anisotropic conductive adhesive after bonding was obtained. The bonded FPC was peeled off, and an anisotropic conductive adhesive (test sample No. 6) on a glass plate having a thin layer of ITO was subjected to measurement. (2) Measurement of Raman spectrum Raman spectrum of anisotropic conductive adhesive in circuit connection product of test sample Nos. 1 to 5 and FPC and glass plate having thin layer of ITO prepared as described above FT-Raman spectrometer (Nippon Bruker RFS-100)
Was measured under the conditions of an excitation laser output of 50 mW, a resolution of 2 cm- ¹ , and a scattering angle of 180 °. (3) Preparation of calibration curve for evaluation of degree of cure In the Raman spectrum of the anisotropic conductive adhesive having various degrees of cure measured as described above, the peak of epoxy group
As (A), the peak area intensity in the wavenumber region of Raman shift value of 3005 cm- ¹ or more and 3020 cm- ¹ or less and the peak of the aromatic ring as a reference peak (B), the Raman shift value of 3035 cm- ¹ or more and 3135
Table 2 shows the results of calculating the Raman intensity ratio (IA / IB) from the peak area intensity in the wavenumber region of cm- ¹ or less. In addition, anisotropic conductive adhesives of various curing degrees (test sample Nos. 1 to 5)
Table 2 shows the results obtained by measuring the DSC reaction rate using a differential scanning calorimeter as an index representing the degree of cure of the polymer. For the differential scanning calorimeter, DuPont Model 912 was used.
0mg and heating from room temperature to 250 ℃ (heating rate 5 ℃
/ Min) was measured. Where D
The SC reaction rate (%) is a value calculated by the equation (1). DSC reaction rate (%) = (1−Qc / Qnc) × 100 (1) Qc; calorific value per 1 g obtained when the anisotropic conductive adhesive after bonding is measured by DSC Qnc; Heated) anisotropic conductive adhesive
Calorific value per g obtained when measured in C

[0012]

[Table 1]

[0013]

[Table 2]

Test samples Nos. 1 to 5 obtained as described above
A calibration curve for evaluating the degree of cure was prepared as shown in FIG. 1 from a correlation diagram between the DSC reaction rate and the Raman intensity ratio (IA / IB). The calibration curve obtained by the method of Example 1 had good linearity and high quantitativeness. (4) Evaluation of Degree of Curing of Anisotropic Conductive Adhesive After Bonding The degree of curing of the anisotropic conductive adhesive after bonding was evaluated using the Raman spectrum of Test Sample No. 6. The Raman intensity ratio of the epoxy group peak (A) and the reference peak of the aromatic ring (B) in the Raman spectrum of the test sample No. 6 (IA /
The calculation method of IB) was the same as the Raman intensity ratio calculation method at the time of preparing the calibration curve. The Raman intensity ratio of the test sample No. 6 obtained by the above method is 0.0075, and by using the calibration curve of FIG.
% Could be evaluated.

(Example 2) The Raman spectrum of the test sample 6 of Example 1 was measured by the microscopic Raman spectroscopy, and the measurement method of the Raman spectrum was changed to 5 μmφ in the same manner as in Example 1. went. For the measurement by microscopic Raman spectroscopy, using a microscopic near-infrared FT-Raman spectrometer (a device in which a dedicated microscope is connected to an RFS-100 manufactured by Bruker Japan with an optical fiber), the excitation laser output is 50 mW, and the resolution is 2 cm.
-1, 100 times objective lens (measurement diameter in this case is 5μmφ
). As shown in FIG. 2, the Raman spectrum measurement site in the test sample 6 is formed by bonding the anisotropic conductive adhesive to the central portion (test sample 6-a) pressed by the heating and pressing head. The non-pressed portion (test sample 6-b) at the end that was not pressed by the heating / pressing head. The Raman intensity ratios in the Raman spectra of the test sample 6-a and the test sample 6-b were 0.075 and 0.111, respectively. From the values of these Raman intensity ratios, the degree of cure of the test sample 6-a and the test sample 6-b could be evaluated as 90% and 51%, respectively, using the calibration curve of FIG. The degree of curing of the uncompressed portion (test sample 6-b) at the end that is not pressed by the heating / pressing head is lower than the degree of curing of the central portion (test sample 6-a) pressed by the heating / pressing head. I was able to evaluate that.

Example 3 (1) Connection Structure Using Anisotropic Conductive Adhesive Anisorm AC-2052 (trade name, manufactured by Hitachi Chemical Co., Ltd., thickness 35 μm, film width 2.0 mm) was replaced with a line width 100 μm. A flexible circuit board (FPC) having a copper circuit having a pitch of 200 μm and a thickness of 35 μm and a glass plate having a thickness of 1.1 mm having a thin layer of indium oxide (ITO) on the entire surface were heated and pressed using a heating and pressing head having a head width of 2 mm. Bonding was performed by heating and pressing at 170 ° C.-2 MPa for 20 seconds. At this time, after the adhesive surface of the anisotropic conductive adhesive is pasted on the FPC in advance, a temporary connection is performed at 80 ° C.-1 MPa for 5 seconds, and then the separator (ethylene tetrafluoride film) is peeled off to adhere to the ITO. went. Thereby, an anisotropic conductive adhesive after bonding was obtained. The bonded FPC was peeled off, and a connection structure (test sample No. 7) made of an anisotropic conductive adhesive on a glass plate having a thin layer of ITO was provided. (2) Evaluation of the degree of curing at 50 μm from the center and the end of the connection structure The Raman spectrum measurement part was connected to the connection structure (test sample 7) using an anisotropic conductive adhesive. Central part of
Except for (test sample 7-a) and a position 50 μm from the end (test sample 7-b), the degree of curing was evaluated in the same manner as in Example 2. FIG. 3 shows a schematic diagram of the measurement site. The Raman intensity ratios in the Raman spectra of the test sample 7-a and the test sample 7-b were 0.075 and 0.80, respectively. From the values of these Raman intensity ratios, the degree of cure (X) of the test sample 7-a was 90% and the degree of cure (Y) of the test sample 7-b was 85% using the calibration curve of FIG. And the degree of cure (Y / X) was 0.94. (3) Evaluation of adhesive strength The adhesive strength was evaluated based on the peel adhesive strength measured when the FPC was peeled off at the time of producing the connection structure. Measurement of adhesive strength is JIS
20 ° C-65% R by 90 degree peeling method based on Z-0237
H. Table 3 shows the evaluation results for the test material 7. Test material 7 having a degree of cure ratio (Y / X) of 0.94
Had high adhesion.

[0017]

[Table 3]

Comparative Example 1 Comparative Example 1 is a comparative example to Example 1. For the test samples Nos. 1 to 5 of Example 1,
As a peak (C) of an epoxy group, a Raman shift value of 1250 cm
- as ^one or more 1280Cm- ¹ or less aromatic ring peak is a reference peak and peak area intensity of wavenumber region (B), the Raman intensity of the Raman shift value 3035Cm- ¹ or 3135Cm- ¹ peak area intensity of the following wavenumber regions A Raman intensity ratio (IC / IB) was obtained in the same manner as in Example 1 except that the ratio was changed to (IC / IB).
(Measurement results are shown in Table 4). The DSC reaction rates and Raman intensity ratios (I
FIG. 4 shows a calibration curve for evaluating the degree of curing from the correlation diagram with C / IB).
Created as follows. The calibration curve obtained by the method of this comparative example had extremely poor linear correlation and low quantitativeness, and was therefore insufficient as a calibration curve for evaluating the degree of cure.

[0019]

[Table 4]

Comparative Example 2 Comparative Example 2 is a comparative example of Example 3. Anisorum AC-2052 (trade name, manufactured by Hitachi Chemical Co., Ltd., thickness 35 μm, film width 2.
0 mm), a line width of 100 μm, a pitch of 200 μm,
Flexible circuit board having a copper circuit with a thickness of 35 μm (F
PC) and a 1.1 mm thick glass plate having a thin layer of indium oxide (ITO) on the entire surface using a heating and pressing head having a head width of 2 mm and connection conditions of 150 ° C.-2 MPa-15.
Bonding was performed by heating and pressing for 2 seconds. At this time, FPC
After adhering the adhesive surface of the anisotropic conductive adhesive on top,
Temporary connection was performed for 5 seconds at MPa, and then the separator (ethylene tetrafluoride film) was peeled off to bond with ITO. Thereby, an anisotropic conductive adhesive after bonding was obtained. The bonded FPC is peeled off, and a connection structure is formed using an anisotropic conductive adhesive on a glass plate having a thin layer of ITO.
(Test sample No. 8) was used for measurement. As described above, the test sample No. 8 was the test sample No. of Example 3. Reference numeral 7 indicates that the connection conditions by heating and pressing were changed. Except that the connection structure using an anisotropic conductive adhesive was changed to the test material 8,
In the same manner as in Example 3, the degree of cure was evaluated at the center (test sample 8-a) and at a position 50 μm from the end (test sample 8-b) of the connection structure. The Raman intensity ratio in the Raman spectrum of the test sample 8-a and the test sample 8-b is
The values were 0.080 and 0.098, respectively. From these Raman intensity ratio values, using the calibration curve of FIG. 2, the degree of cure (X) of the test sample 8-a was 85%, and the degree of cure (Y) of the test sample 8-b was 65%. , The degree of cure (Y / X) is 0.1.
76. As shown in Table 3, the test material 8 evaluated by the same evaluation method as in Example 3 had a low adhesive strength.

[0021]

As described in detail above, by using the method for evaluating the degree of curing of the anisotropic conductive adhesive according to the present invention, the degree of curing of the anisotropic conductive adhesive after bonding can be measured on a circuit board or the like. It can be easily evaluated on the adherend. In addition, 1 μm or more
Since the evaluation can be performed at a minute portion of 00 μm or less, it is also possible to evaluate the difference in the degree of curing of the anisotropic conductive adhesive at each site on the adherend. Furthermore, by using the method for evaluating the degree of cure in the anisotropic conductive adhesive according to the present invention, the degree of cure in the connection structure by the anisotropic conductive adhesive was evaluated, and each part of the connection structure was evaluated. It was possible to find a connection condition under which the resin was sufficiently cured, thereby making it possible to provide a connection structure using an anisotropic conductive adhesive, which was confirmed to have sufficiently cured each part. As described above, in the anisotropic conductive adhesive, the degree of curing, which is one of the important properties, can be evaluated in more detail for the anisotropic conductive adhesive bonded under actual connection conditions. The method for evaluating the degree of curing and the connection structure in the anisotropic conductive adhesive are extremely useful in industry.

[Brief description of the drawings]

FIG. 1 is a calibration curve prepared by the method of Example 1 of the present invention for obtaining a degree of cure, that is, a graph showing a correlation between a DSC reaction rate and a Raman intensity ratio.

FIG. 2 is a schematic diagram showing the measurement positions of the Raman spectrum of test sample 6 (test samples 6-a and 6-b) in Example 2 of the present invention.

FIG. 3 is a schematic diagram showing the measurement positions of the Raman spectrum of the test sample 7 (test samples 7-a and 7-b) in Example 3 of the present invention.

FIG. 4 is a calibration curve for obtaining a degree of cure prepared by a method of the related art (Comparative Example 1), that is, a graph showing a correlation between a DSC reaction rate and a Raman intensity ratio.

FIG. 5 is a schematic diagram showing the measurement positions of the Raman spectrum of the test sample 8 (test samples 8-a and 8-b) in Comparative Example 2 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass plate which has a thin layer of ITO 2 Anisotropic conductive adhesive 3 End part which is not pressed by a heating and pressing head 4 Center part which is pressed by a heating and pressing head 5 Measurement part of Raman spectrum (test sample 6-b 6) Raman spectrum measuring section (test sample 6-a) 7 Raman spectrum measuring section (test sample 7-a) 8 Raman spectrum measuring section (test sample 7-b) 9 Raman spectrum measuring section ( Test sample 8-a) 10 Measurement section (Test sample 8-b) 11 Thin layer of ITO 12 Glass plate 13 Connection structure

Continued on the front page (72) Inventor Isao Tsukakoshi 1150 Goshomiya, Shimodate, Ibaraki Pref. EE30 5G307 HA02 HB03 HC01

Claims (4)

[Claims] 1. An anisotropic conductive adhesive containing an epoxy resin, a curing agent and conductive particles, the peak intensity of an epoxy group having a Raman shift value in the Raman spectrum within the range of 2990 cm- ^{1 to} 3025 cm- ^1. A method for evaluating the degree of curing of an anisotropic conductive adhesive, wherein the method comprises evaluating the degree of curing using the method. Wherein the aromatic ring in the Raman shift value 2990Cm- ¹ or 3025Cm- ¹ or less in the range peak (A) and 3150 cm-1 or less of the Raman shift value 3025cm-1 or more epoxy groups in the range of the Raman spectrum Raman intensity ratio with peak (B)
The method for evaluating the degree of cure of an anisotropic conductive adhesive according to claim 1, wherein the degree of cure is evaluated using (IA / IB). 3. The method for evaluating the degree of cure of an anisotropic conductive adhesive according to claim 1, wherein the measured diameter of the Raman spectrum is a minute portion of 1 μm or more and 100 μm or less. 4. The anisotropic conductive adhesive according to claim 3, wherein the degree of curing of the anisotropic conductive adhesive evaluated using the method for evaluating the degree of curing satisfies the following two conditions. Connection structure using one side conductive adhesive. (1) Curing degree (X) measured at a position within a radius of 100 μm from the center of the connector and a radius of 10 from the end of the connector.
Ratio (Y / X) to the degree of cure (Y) measured at a position within 0 μm
Is 0.8 or more and 1.2 or less. (2) The degree of cure (X) and the degree of cure (Y) are both 70% or more.