JP2006137924A - Electroconductive resin composition, electroconductive resin cured product, and electronic component module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electroconductive resin cured product in which a high connection reliabilty can be acquired. <P>SOLUTION: The electroconductive resin composition for electrically connecting between conductive materials contains an electroconductive powder and a resin material which, after adsorbing on the surface of the conductive material, attains an increase amount in the work function on the above surface of the conductive material to 0.6 eV or less, consequently increasing the value of the Schottky electrical current flowing by the way of the resin material, and is characterized in that the above resin material contains an epoxy resin consisting of a straight-chained hydrocarbon and glycidyl ether. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a conductive resin composition used to obtain high connection reliability between conductors, a cured conductive resin, and an electronic component module using the same.

  A conductive resin composition may be used to electrically connect conductors of a plurality of electronic components. The conductive resin composition used for this type of application is required to have high connection reliability.

  As such a conductive resin composition, Patent Document 1 includes a conductive powder and a resin material. The resin material is a bisphenol-type epoxy resin, and the cured molecular structure is more than that of the bisphenol-type epoxy resin. A conductive adhesive using a resin in which a biphenyl type epoxy resin and a trifunctional phenol type epoxy resin, which are resins having little translational and rotational motion, are described.

Patent Document 2 includes conductive particles and a resin, and 40% by weight or more of the conductive particles are substantially composed of silver and tin, and the molar ratio of silver: tin is 2.5: 1.5 to 3.5: A conductive adhesive that is 0.5 silver-tin powder is described.
JP 2000-319622 A JP 2002-265920 A

  In the conductive adhesive described in Patent Document 1, since the bonding strength between the conductor and the conductive adhesive is improved by adopting the above composition, the conductor and the conductive adhesive obtained by curing the conductive adhesive are used. It is said that the reliability of electrical connection with the cured agent is improved.

  Moreover, in the electroconductive adhesive described in patent document 2, it is supposed that silver migration can be suppressed and high reliability can be obtained by using electroconductive particles as silver-tin alloy powder.

  However, in Patent Document 1, since a resin having a small translation / rotation motion or a large number of reactive groups is used, the free volume in the cured product of the conductive adhesive is increased and at the same time contributes to the curing reaction. The number of functional groups left unsuccessful becomes relatively large. As a result, the moisture permeability rate in the bulk increases due to the large free volume, and at the same time, the water absorption rate increases and the swelling rate increases. Therefore, since the Schottky current flowing through the resin component is reduced in the cured conductive adhesive, the electrical connection reliability in the cured product is reduced. In other words, the effect of improving the electrical connection reliability between the conductor and the cured product is offset by the effect of reducing the electrical connection reliability in the cured product, and as a result, a device composed of the conductor and the cured product. As a result, there is a problem that the reliability of electrical connection as is not so improved.

  On the other hand, in the said patent document 2, in order to mix | blend silver-tin alloy powder, the Schottky current which flows between a conductive adhesive hardened | cured material or between a conductive adhesive hardened | cured material and a conductor is low, and mix | blended silver powder. There was a problem that the resistance value was higher than that.

  In this way, as a result of suppression of joint strength sawing and migration in order to increase electrical connection reliability, the Schottky current is reduced, and as a result, electrical connection reliability is improved. There is no current situation.

  Therefore, the present invention focuses on the Schottky current flowing through the resin component and aims to improve the electrical connection reliability by increasing the value of the Schottky current. Furthermore, it aims at providing the conductive resin hardened | cured material which can acquire high connection reliability also in hardened | cured material, and an electronic component module using the same.

  The Schottky current depends on the work function of the surface of the conductive metal that is the adherend of the conductive resin, and the work function is varied in size by adsorbing the adherend such as the conductive resin on the surface of the conductive metal. It is known that the value of the Schottky current increases as the value changes, and as the work function decreases.

  Therefore, as a result of diligent research focusing on this, the present inventors have obtained high connection reliability with respect to the conductor by using a resin material with a small increase in the work function of the conductor surface after adsorption onto the conductor surface. It has been found that a conductive resin composition that can be provided is provided.

  In order to achieve the above object, a conductive resin composition according to the present invention is a conductive resin composition for electrically connecting conductors, and after adsorbing the conductive powder and the conductor surface, And a resin material having an increase in work function on the conductor surface of 0.6 eV or less.

  In the conductive resin composition according to the present invention, the resin material is represented by [Chemical Formula 1] consisting of a linear hydrocarbon and glycidyl ether (where n represents an integer of 3 to 10). ) An epoxy resin is included.

  In addition, when n is less than 3 in the [Chemical Formula 1] formula, the concentration of the cross-linking points is increased, the stress is increased, and a high adhesive force cannot be obtained. Moreover, when n exceeds 10, since the intensity | strength of resin cured material itself becomes weak, it is unpreferable.

  Alternatively, the conductive resin composition according to the present invention is characterized in that the resin material includes an epoxy resin containing a functional group represented by [Chemical Formula 2] and glycidyl ether in the molecular structure.

  Moreover, the conductive resin composition according to the present invention is characterized in that the resin material includes an epoxy resin represented by [Chemical Formula 3] containing cyclohexane and glycidyl ether in a molecular structure.

  Furthermore, the conductive resin composition according to the present invention further includes an organic substance containing nitrogen.

  The organic substance having nitrogen is preferably at least one selected from aliphatic amines and polyamines, and more specifically, selected from 1-aminodecane, di-n-butylamine, triethylamine, and tetraethylenepentamine. It is preferable that it is at least one kind.

  Moreover, the conductive resin cured product according to the present invention is obtained by curing the conductive resin composition according to any one of claims 1 to 8.

  An electronic component module according to the present invention includes a first electronic component including a first element body and a first outer conductor formed on a surface of the first element body, a second element body, The second electronic component including a second outer conductor formed on the surface of the second element body is electrically connected to the first outer conductor and the second outer conductor. The conductive resin cured product described in 1. above.

  Since the conductive resin composition of the present invention includes a resin material having a small increase in work function on the conductor surface after being adsorbed on the conductor surface, the inside of the cured conductive resin obtained by curing the conductive adhesive composition and Electrical connection reliability can be increased between the cured conductive resin and the conductor.

  More specifically, (1) an epoxy resin represented by [Chemical Formula 1] composed of a linear hydrocarbon and glycidyl ether, and (2) a functional group represented by [Chemical Formula 2] and glycidyl in the molecular structure. An epoxy resin containing an ether, and (3) an epoxy resin represented by [Chemical Formula 3] containing cyclohexane and glycidyl ether in the molecular structure. The increase amount of the function can be reduced, and the electrical connection reliability can be improved.

  Furthermore, the increase in the work function of the conductor surface can be further reduced by including an organic substance having nitrogen in addition to the resin materials (1) to (3). In order to reduce the increase in the work function of the conductor surface, an aliphatic amine or polyamine is effective as the nitrogen-containing compound. More specifically, 1-aminodecane, di-n-butylamine, triethylamine, Tetraethylenepentamine is effective.

  Hereinafter, the conductive resin composition, the cured conductive resin, and the electronic component module of the present invention will be described with reference to the drawings.

  FIG. 1 is a plan view showing a test substrate using the cured conductive resin of the present invention. FIG. 1A is a plan view seen from the front surface of the substrate, and FIG. 1B is a plan view seen from the back surface of the substrate. FIG. 2 is a cross-sectional view taken along line AA in FIG.

  The test substrate includes a substrate 3 serving as a main body, a base electrode 4 and an electrode 2 formed on the surface of the substrate 3, and a cured conductive resin 1 formed on the surface of the electrode 2.

  The substrate 3 is made of, for example, a glass-epoxy composite material, and a through hole 5 is formed in the substrate 3. Further, the electrode 2 is formed so as to extend over the upper and lower surfaces of the substrate through the through hole 5.

  The cured conductive resin 1 is obtained by curing the conductive resin composition of the present invention. The cured conductive resin 1 is formed, for example, by applying a conductive resin composition on the substrate 3 by screen printing and thermally curing the conductive resin composition.

  The base electrode 4 and the electrode 2 are made of, for example, Cu, Ag, Au, Sn, Ni, etc., and can be formed by a known process such as electroless plating.

  By configuring the test substrate as described above using the cured conductive resin 2 according to the present invention, a test substrate having high reliability of electrical connection between the electrodes 2 and 2 can be obtained.

  In addition, about the formation method of the conductive resin hardened | cured material 1, the electrode 2, and the base electrode 4, it does not specifically limit to the said method.

  FIG. 3 is a schematic cross-sectional view showing an electronic component module using the cured conductive resin of the present invention. As shown in FIG. 3, the electronic component module 100 includes a multilayer ceramic capacitor 110 and a printed circuit board 120 for mounting the multilayer ceramic capacitor 110.

  The multilayer ceramic capacitor 110 includes a ceramic body 111 and an external conductor 112 formed on the surface of the ceramic body 111. An internal electrode (not shown) is formed inside the ceramic body 111 made of dielectric ceramics, and the internal electrode is electrically connected to the external conductor 112, and a capacitance is generated between the two external conductors 112. Is configured to do. The surface of the outer conductor 112 is made of, for example, Sn or Au.

  The printed circuit board 120 includes a resin substrate 121 and an external conductor 122 formed on the surface of the resin substrate 121. The surface of the outer conductor 122 is made of, for example, Sn or Au.

  The outer conductor 112 and the outer conductor 122 are electrically connected through the cured conductive resin 130 of the present invention.

  By configuring the electronic component module as described above, it is possible to obtain an electronic component module with high reliability of electrical connection between the outer conductor 112 of the multilayer ceramic capacitor 110 and the outer conductor 122 of the printed circuit board 120. it can.

  In the present embodiment, a multilayer ceramic capacitor is used as the first electronic component, but other chip components and semiconductor components can also be used. Further, although a printed circuit board is used as the second electronic component, a ceramic multilayer board or the like can also be used. Further, not only a module in which chip components are mounted on a substrate, but also any type of module as long as it has a structure for electrically connecting conductors using the cured conductive resin of the present invention. It may be.

  Hereinafter, experimental examples in the present invention will be described.

Experimental example 1

(1) Preparation of conductive resin composition First, spherical silver powder having an average particle size of 1.9 µm was prepared as the conductive powder. Next, 1,6-hexanediol diglycidyl ether (wherein n represents an integer of 3 to 10) represented by [Chemical Formula 1] composed of a linear hydrocarbon and glycidyl ether is used. In [Chemical Formula 1], n = 6) was prepared. Moreover, as an epoxy resin containing a functional group represented by [Chemical Formula 2] and glycidyl ether in the molecular structure, a tertiary butyl type epoxy resin represented by [Chemical Formula 4] and a phenol novolac type represented by [Chemical Formula 5] An epoxy resin, 1,4-cyclohexanedimethanol diglycidyl ether represented by [Chemical Formula 3], and a glycidylamine type epoxy resin represented by [Chemical Formula 6] (outside the scope of the present invention) were prepared. Furthermore, an epoxy-amine adduct compound (manufactured by Ajinomoto Fine Techno, trade name: MY-HK) was prepared as an amine adduct compound.

Next, these starting materials were mixed in the proportions shown in Table 1 below, and then stirred for 30 minutes using a mixer to obtain five types of conductive resin compositions.
(2) Evaluation of Contact Resistance For measurement of contact resistance, a measurement substrate 10 shown in FIG. 4 was prepared. The measurement substrate 10 includes a Cu plate 11 having a length of 40 mm, a width of 10 mm, and a thickness of 1 mm, and a measurement pattern 12 formed on the Cu plate 11 and made of a cured conductive resin.

  A method for manufacturing the measurement substrate 10 will be described. First, a Cu plate 11 was prepared, and the surface was cleaned for 10 minutes using an ultrasonic cleaner. Next, each of the five types of conductive resin compositions obtained in (1) was applied to the surface of the cleaned Cu plate 11 using screen printing as shown in FIG. The measurement pattern 12 made of a cured conductive resin was formed on the Cu plate 11 by heating at 150 ° C. for 2 hours.

  Next, using a micro ohm meter, between the measurement pads 21 and 22 of the measurement pattern 12 shown in FIG. 5, between the measurement pads 22 and 23, between the measurement pads 23 and 24, between the measurement pads 24 and 25, and between the measurement pads 25. , 26 was measured for resistance (mΩ). Moreover, the distance (mm) between the adjacent patterns 12 for a measurement typically shown with the arrow in FIG. 6 was measured using the metal microscope.

The relationship between the distance (mm) between the adjacent measurement patterns 12 and the resistance value (mΩ) between the measurement pads 21 to 26 (for example, the leftmost measurement pattern 12 in FIG. 6 and the measurement pattern 12 adjacent thereto). The resistance value corresponding to the distance (mm) is the resistance value (mΩ) between the measurement pads 21 and 22 in FIG. 5) using a least-square method to obtain a resistance at a distance of 0 (mm). A value (mΩ) was obtained, and a value obtained by halving the value was defined as a contact resistance value (mΩ).
(3) Evaluation of work function First, 1 wt% of each of the epoxy resins used in the conductive resin composition prepared in (1) was dissolved in acetone to obtain an epoxy resin solution. Next, the Cu plate was immersed in the epoxy resin solution, and ultrasonic dispersion was performed for 10 minutes. After the ultrasonic dispersion, the sample was allowed to stand for 12 hours in a state immersed in an epoxy resin solution. Next, the Cu plate was taken out of the epoxy resin solution and dried in the air for 24 hours.

  Next, the work function of the Cu plate was measured using an air atmosphere type ultraviolet photoelectron analyzer (manufactured by Riken Keiki Co., Ltd., equipment name: AC-2). In the measurement, each of the Cu plate immersed in the epoxy resin solution and the Cu plate not immersed in the epoxy resin solution were measured, and the amount of increase in work function was calculated using the calculation formula shown in the following equation (1). did.

Increase amount of work function = (work function of Cu plate immersed in epoxy resin solution) − (work function of Cu plate not immersed in epoxy resin solution) (1)
The amount of increase in work function obtained by Equation 1 was defined as “work function change amount” due to adsorption of each epoxy resin.

  Table 1 shows the composition of the conductive resin composition prepared in (1) and the work function variation and the contact resistance value measured by the methods (2) and (3) for each of the compositions. In Table 1, sample number 5 with * added to the sample number is a comparative example outside the scope of the present invention.

  As apparent from Table 1, the contact resistance values of sample numbers 1 to 4 are low because the increase in work function is as small as 0.6 eV or less. On the other hand, for sample number 5, the increase in the work function exceeds 0.6 eV, so the contact resistance value is high.

Experimental example 2

(1) Preparation of conductive resin composition First, as starting materials, spherical silver powder having an average particle diameter of 1.9 μm, 1,6-hexanediol diglycidyl ether, and the tertiary butyl type epoxy resin shown in [Chemical Formula 4] 1,4-cyclohexanedimethanol diglycidyl ether shown in [Chemical Formula 3] and an epoxy-amine adduct compound (manufactured by Ajinomoto Fine Techno Co., Ltd., trade name: MY-HK) were prepared. Furthermore, tetraethylenepentamine, 1-aminodecane, di-n-butylamine, and triethylamine were prepared as organic substances having nitrogen. Furthermore, polybutadiene was prepared for comparison with organic substances having nitrogen.

  In addition, in the tertiary butyl type epoxy resin shown in [Chemical Formula 4], the tertiary butyl group (functional group shown in [Chemical Formula 2]) may be bonded to any carbon atom of the benzene ring.

Next, after mixing these starting materials in the ratio shown in Table 2 below, the mixture was stirred for 30 minutes using a mixer to obtain conductive resin compositions of sample numbers 6 to 10. The addition amount of the organic substance having nitrogen is the resin material (1,6-hexanediol diglycidyl ether, tertiary butyl epoxy resin shown in [Chemical Formula 4], 1,4-cyclohexane shown in [Chemical Formula 3]. The total amount of dimethanol diglycidyl ether and epoxy-amine adduct compound) is 100 parts by weight. In addition, although polybutadiene is not an organic substance containing nitrogen, it is described in the column of an organic substance containing nitrogen for convenience. Moreover, in order to verify the effect of adding the organic substance containing nitrogen, the sample number 1 used in Experimental Example 1 not containing the organic substance containing nitrogen was produced again.
(2) Evaluation of contact resistance and work function The conductive resin composition was tested under the same conditions as in Experimental Example 1 except that the substrate was replaced with a glass substrate whose surface was coated with ITO (In ₂ O ₃ —SnO ₂ ). Contact resistance and substrate work function were evaluated.

  Table 2 shows the composition of Sample Nos. 1, 6 to 10, the amount of change in work function, and the contact resistance value. In Table 2, sample number 10 with * added to the sample number is a comparative example outside the scope of the present invention.

  As is clear from the comparison between Sample No. 1 and Sample Nos. 6 to 9, the increase in work function can be further reduced by containing an organic substance having nitrogen, and as a result, the contact resistance value can be reduced. . In Sample No. 10 containing polybutadiene, the amount of increase in work function was larger than that in Sample No. 1, and the contact resistance value was increased.

  As is clear from Sample Nos. 11 and 12, an epoxy resin other than 1,6-hexanediol diglycidyl ether within the scope of the present invention may contain an organic substance having nitrogen. In Sample Nos. 11 and 12, the increase in work function could be kept low, and the contact resistance could be reduced.

  Furthermore, as apparent from Sample No. 13, the amount of increase in work function can be reduced by using a mixture of two or more epoxy resins within the scope of the present invention and further containing an organic substance containing nitrogen. It was.

  In the conductive resin composition excluding the diluting solvent, the conductive powder is represented by [Chemical Formula 1] consisting of 78 to 95% by weight of linear hydrocarbon and glycidyl ether (where n is 3 Epoxy resin containing 1 to 20% by weight, and an epoxy resin containing a functional group represented by [Chemical Formula 2] and glycidyl ether in the molecular structure in an amount of 1 to 20)% by weight. It is preferable. Moreover, it is preferable that 0.001-20 weight part of the organic substance which has nitrogen is contained with respect to 100 weight part of all the resin contained in a conductive resin composition.

  Moreover, even if the shape of the metal powder used for the conductive resin composition is any shape such as a spherical shape, a flake shape, and a needle shape, the same effect as the present invention can be obtained. Moreover, about the kind of metal powder, it is preferable that it is a metal powder which consists of at least 1 sort (s) of Ag, Cu, or Ni as described in a present Example.

  In the present invention, the epoxy resin represented by [Chemical Formula 4] or [Chemical Formula 5] is used as an epoxy resin composed of a functional group represented by [Chemical Formula 2] and glycidyl ether in the molecular structure. Even when an epoxy resin composed of a functional group represented by [Chemical Formula 2] and glycidyl ether is used, the same effect as in the present invention can be obtained.

  Furthermore, in the present invention, an epoxy-amine adduct compound (manufactured by Ajinomoto Fine Techno Co., Ltd., trade name: MY-HK) is used as the amine adduct compound. Is obtained. Needless to say, any other curing agent or curing accelerator may be blended. Moreover, you may mix | blend additives, such as an organic solvent, a reactive diluent, a rheology regulator, and an antifoamer, as needed.

3 is a plan view showing a test substrate of Example 1. FIG. It is sectional drawing along the AA line in FIG. 6 is a schematic cross-sectional view showing an electronic component module of Example 2. FIG. It is a top view which shows the board | substrate for a measurement. It is a schematic diagram which expands and shows the measurement pattern of the measurement substrate. It is a schematic diagram which expands and shows the measurement pattern of the measurement substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive resin cured material 2 Electrode 3 Substrate 4 Base electrode 5 Through hole 100 Electronic component module 110 Multilayer ceramic capacitor 111 Ceramic body 112 External electrode 120 Printed circuit board 121 Resin substrate 122 External electrode 130 Conductive resin cured material 10 For measurement Substrate 11 Cu plate 12 Measurement pattern 21-26 Measurement pad

Claims (10)

A conductive resin composition for electrically connecting conductors,
Conductive powder;
A conductive resin composition comprising: a resin material having an increase in work function of the conductor surface of 0.6 eV or less after being adsorbed on the conductor surface. The resin material includes an epoxy resin represented by [Chemical Formula 1] composed of a linear hydrocarbon and glycidyl ether (wherein n represents an integer of 3 to 10). The conductive resin composition described in 1.
The conductive resin composition according to claim 1, wherein the resin material includes an epoxy resin including a functional group represented by [Chemical Formula 2] and glycidyl ether in a molecular structure.
The conductive resin composition according to claim 1, wherein the resin material includes an epoxy resin represented by [Chemical Formula 3] including cyclohexane and glycidyl ether in a molecular structure.
  The conductive resin composition according to any one of claims 1 to 3, further comprising an organic substance containing nitrogen.   6. The conductive resin composition according to claim 5, wherein the organic substance having nitrogen is at least one selected from aliphatic amines and polyamines.   The conductive resin composition according to claim 6, wherein the aliphatic amine is at least one selected from 1-aminodecane, di-n-butylamine, and triethylamine.   The conductive resin composition according to claim 6, wherein the polyamine is tetraethylenepentamine.   A conductive resin cured product obtained by curing the conductive resin composition according to any one of claims 1 to 8. A first electronic component comprising a first element body and a first outer conductor formed on the surface of the first element body;
A second electronic component comprising a second element body and a second outer conductor formed on the surface of the second element body;
An electronic component module comprising: the cured conductive resin according to claim 9 that electrically connects the first outer conductor and the second outer conductor.