JP4482945B2 - Electronic component module - Google Patents

Description

  The present invention relates to an electronic component module, and more particularly to an electronic component module in which electronic components are electrically connected via a bonding material.

  Electronic components such as multilayer ceramic capacitors and semiconductor elements have external electrodes to be electrically connected to other electronic components such as circuit boards, and bonding materials such as solder and conductive resin material applied to the external electrodes It is electrically connected to other electronic components via

  In recent years, it has been requested to reduce the use of lead from the viewpoint of the environment and the like. From such a viewpoint, as the bonding material, a conductive resin material can be used as an alternative to the conventionally used solder. Such conductive adhesives are attracting attention.

  In order to improve the reliability of the electrical connection, it is important to improve the reliability of the electronic component itself, and at the same time, it is important to improve the reliability of the connection part with other electronic components. The reliability of the connection part between electronic components includes the resistance value and moisture resistance of the connection material itself such as conductive resin material, as well as the connection resistance and connection strength of the contact part between the connection material and the electrode. Influenced by reliability.

  Therefore, conventionally, there has been known a technique for improving the connection reliability by performing some kind of surface treatment on the electrode surface. For example, Patent Document 1 proposes a method for manufacturing an electronic circuit board in which a metal surface is previously treated with a coupling agent such as a silane, and then a conductive paste is applied or printed.

  According to Patent Document 1, it is said that the adhesion between the metal surface and the conductive paste cured coating film is enhanced by treating the metal surface with a silane-based coupling agent in advance.

JP-A-6-61602

  When electrical connection between the electrodes is performed using a conductive resin material, conduction between the conductive resin material and the electrodes is performed by a Schottky current. It is known that the Schottky current depends on the work function of the metal surface, and that the value of the Schottky current increases as the work function decreases. Further, it is known that the work function of the material surface varies in various sizes by adsorbing other materials on the surface.

  However, the invention described in Patent Document 1 improves adhesion by surface treatment with a silane-based coupling agent, and does not focus on the work function or Schottky current. Rather, since the silane coupling agent specifically exemplified in Patent Document 1 has a highly electron withdrawing oxygen atom in the molecular skeleton, the work function of the electrode surface is increased and the Schottky current is decreased. It is done.

  The present invention provides an electronic component module with high electrical connection reliability by reducing the connection resistance value between the electrode and the connection material by reducing the work function of the electrode surface and increasing the Schottky current. For the purpose.

  In order to achieve the above object, an electronic component module according to the present invention is an electronic device in which a first electronic component having an external electrode and a second electronic component having an external electrode are electrically connected via a bonding material. In the component module, the bonding material is made of a conductive adhesive, and on the surface of at least one of the external electrodes of each of the first and second electronic components, An organic compound that lowers the work function is adsorbed.

  In the electronic component module of the present invention, the organic compound is an amine compound having no nitrogen atom and having a nitrogen atom in the molecular skeleton, specifically, tetraethylenepentamine, Triethylamine, tri-n-butylamine and 1-aminodecane can be preferably used.

  Furthermore, the electronic component module of the present invention is characterized in that the electrode surface includes one selected from Au, Ag, Sn, and alloys thereof.

  The electronic component module of the present invention is characterized in that the conductive adhesive is formed of any one of a conductive resin material and a conductive adhesive sheet.

  According to the electronic component module of the present invention, the bonding material for electrically connecting the first electronic component and the second electronic component is made of a conductive adhesive, and each of the first and second electronic components is provided. Since the organic compound that lowers the work function of the electrode surface is adsorbed on the surface of at least one of the external electrodes, the work function of the electrode surface is lowered and the Schottky current is increased. Thus, the connection resistance between the electrode and the conductive adhesive can be reduced, and the reliability of the electrical connection between the first electronic component and the second electronic component can be improved.

  As the organic compound, an amine compound having no oxygen atom in the molecular skeleton and having a nitrogen atom, specifically, tetraethylenepentamine, triethylamine, tri-n-butylamine, or 1-aminodecane is used. As a result, the work function of the electrode surface can be effectively reduced.

  Further, since the surface of the external electrode contains at least one selected from Au, Ag, Sn, and alloys thereof, when the metal material normally used as the external electrode is used, the electrode and the conductive adhesive are bonded. The connection resistance between the agents can be effectively reduced, and the reliability of the electrical connection between the first electronic component and the second electronic component can be improved.

  In addition, since the conductive adhesive is formed of either a conductive resin material or a conductive adhesive sheet, the reliability of electrical connection is ensured even when a lead-free bonding material is used. An improved electronic component module can be realized.

It is sectional drawing which shows the electronic component module of this invention. It is a top view of the board | substrate for a test. It is AA sectional drawing of FIG.

Explanation of symbols

10 Multilayer ceramic electronic component (first electronic component)
12 External electrode 20 Circuit board (second electronic component)
22 Electrode pad (external electrode)
30 Bonding material

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a sectional view schematically showing one embodiment of an electronic component module according to the present invention.

  In the electronic component module, a multilayer ceramic electronic component 10 as a first electronic component and a circuit board 20 as a second electronic component are electrically connected via a bonding material 30 made of a conductive resin material. .

  The multilayer ceramic electronic component 10 includes a ceramic base 11 as an electronic component main body and an external electrode 12 formed on the surface of the ceramic base 11. The ceramic substrate 11 is made of a ceramic material such as dielectric ceramics or magnetic ceramics, and has internal electrodes built-in, but is not shown in the present embodiment.

  The surface layer of the external electrode 12 contains Ag, Au, Sn or an alloy thereof, and an organic compound that lowers the work function on the surface of the external electrode 12, such as tetraethylenepentamine, triethylamine, tri-n-butylamine. An amine compound having no nitrogen atom and having a nitrogen atom in a branched skeleton such as 1-aminodecane is adsorbed in advance.

  That is, before the conductive resin material that is the bonding material 30 is applied between the external electrode 12 and the electrode pad 22, the multilayer ceramic electronic component 10 is subjected to a surface treatment, whereby the organic compound becomes a surface layer of the external electrode 12. (Surface) is adsorbed.

  The circuit board 20 includes a substrate body 21 formed of a resin material or aluminum oxide, and electrode pads (external electrodes) 22 formed on the main surface of the substrate body 21. Similar to the external electrode 12, the surface layer of the electrode pad 22 contains Ag, Au, Sn, or an alloy thereof, and an organic compound that lowers the work function on the surface of the electrode pad 22, such as tetraethylenepentamine, A branched skeleton such as triethylamine, tri-n-butylamine, 1-aminodecane or the like has no oxygen atom and an amine compound having a nitrogen atom is adsorbed in advance.

  That is, before the conductive resin material as the bonding material 30 is applied between the external electrode 12 and the electrode pad 22, the circuit board 20 is subjected to a surface treatment, whereby the organic compound is applied to the surface layer (surface) of the electrode pad 22. ).

  As a method of adsorbing these organic compounds to the surface layer of the external electrode 12 or the electrode pad 22, after diluting these organic compounds with a solvent such as ethanol as necessary, immersion (dipping), spraying (spraying), Although there is a method of applying to the surface layer of the external electrode 12 and the electrode pad 22 by a method such as transfer or application using a brush, and drying the solvent, it is not limited to this.

  The conductive resin material forming the bonding material 30 includes a resin such as an epoxy resin and a conductive powder made of Ag or the like, and is applied between the external electrode 12 and the electrode pad 22 and then thermally cured or ultraviolet cured. It is cured by such a method.

  As described above, in the electronic component module, since the organic compound that lowers the work function is adsorbed in advance on the surface layers of the external electrode 12 and the electrode pad 22, conduction between the external electrode 12 or the electrode pad 33 and the bonding material 30 is performed. Increases the value of the Schottky current that bears. As a result, each of the connection resistance between the external electrode 12 and the conductive resin material 30 and the connection resistance between the electrode pad 22 and the bonding material 30 are reduced. As a result, the connection between the external electrode 12 and the electrode pad 22 is reduced. The connection resistance between them is reduced, and the reliability of the electrical connection between the ceramic electronic component 10 and the circuit board 20 is improved.

  The present invention is not limited to the above embodiment. In the above embodiment, the organic compound that lowers the work function is adsorbed on the surface layers of both the external electrode 12 and the electrode pad 22, but the work function is reduced only on the surface layer of either the external electrode 12 or the electrode pad 22. The same effect can be obtained even if the organic compound to be adsorbed is adsorbed.

  Moreover, in the said embodiment, although the tetraethylenepentamine, the triethylamine, the tri-n-butylamine, and 1-aminodecane were illustrated as a suitable organic compound adsorb | sucked on the electrode surface, it is not limited to these. That is, any amine compound having no oxygen atom in the molecular skeleton and having a nitrogen atom in the molecular skeleton can be preferably used. For example, allylamine, methylamine, ethylamine, aminopentane, propyl Amine, butylamine, i-butylamine, t-butylamine, pentylamine, cyclohexylamine, octylamine, decylamine, decylamine, laurylamine, phenethylamine, diaminopentane, dodecamemethylenediamine, methylbenzylamine, ethylbenzylamine, methylcyclohexylamine, ethylenediamine , Heptylamine, hexamethylenediamine, hexylamine, nonamethylenediamine, octamethylenediamine, phenylenediamine, phenylmethylamine, phenylethylamine , Phenyl naphthylamine, diaminobutane, tetramethylethylenediamine, tetramethylphenylenediamine, tetramethylenepropanediamine, xylenediamine and other primary amines, dicyclohexylamine, diallylamine, dimethylamine, diethylenetriamine, dipropylamine, dipropylethylamine, dibutylamine , Secondary amines such as dihexylamine, dimethylphenylenediamine, dimethylbenzylamine, dimethylethylenediamine, dimethyloctylamine, dimethylpropanediamine, dipropylamine, dipropylenetriamine, trimethylamine, triethylamine, tripropylamine, tributylamine, triphenyl Amine, trioctylamine, trimethylenediamine, triethylenedi And the like can be used tertiary amines such as Min. Furthermore, the organic compound adsorbed on the electrode surface may be a mixture of two or more of the above-described organic compounds, and the material of the electrode surface is not limited to the above.

  In the above embodiment, a conductive resin material is used as the bonding material 30. However, any conductive adhesive may be used, and the same effect can be obtained even when a conductive adhesive sheet or the like is used.

  Further, the form of the first electronic component and the second electronic component is not limited to the above-mentioned multilayer ceramic electronic component and circuit board, but can be applied to any electronic component such as a multilayer substrate and a semiconductor element. Needless to say.

  Next, specific examples of the present invention will be described.

  FIG. 2 is a plan view showing a test substrate used in this example, and FIG. 3 is a cross-sectional view taken along the line AA of FIG.

  The test substrate extends to both main surfaces of the substrate body 41 through a substrate body 41 made of a glass-epoxy composite material, through holes 42a and 42b formed in the substrate body 41, and the through holes 42a and 42b. The electrodes 43a and 43b formed as described above and the conductive resin material 44 as a bonding material applied so as to connect the electrodes 43a and 43b. The electrodes 43a and 43b have a two-layer structure including a base layer made of Cu having a thickness of 10 μm and a surface layer having a thickness of 1 μm formed so as to cover the base layer.

  In addition, as the surface layer material of the electrode, a material different depending on each sample, specifically, any one of Sn, Ag, Au, and Sn-37Pb was used.

  Next, the following experiment was performed using the test substrate.

(1) Measurement of work function of electrode surface Prepare the above-mentioned test substrate having a different surface layer material and immerse it in a 0.1 mol / L hydrochloric acid aqueous solution for 1 hour to remove the oxide film on the surface. ) For 10 minutes, rinsed with ethanol, and then air-dried for 24 hours or more to volatilize ethanol. Thereafter, the work function on the surfaces of the electrodes 43a and 43b of each sample was measured using an atmospheric-type ultraviolet photoelectron analyzer (AC-2 manufactured by Riken Keiki Co., Ltd.).

(2) Electrode surface treatment (adsorption treatment of organic compounds)
Tetraethylenepentamine as the organic compound _{[NH (C 2 H 4 NHC} 2 H 4 NH 2) 2], triethylamine _{[(C 2 H 5) 3} N], tri -n- butylamine _{[(CH 3 (CH 2)} 3 ) ₃ N], 1-aminodecane [CH ₃ (CH ₂ ) ₉ NH ₂ ], triethanolamine [(C ₂ H ₄ OH) ₃ N], decanoic acid [C ₉ H ₁₉ COOH] It diluted with ethanol so that content of a compound might be 0.5 wt%, and prepared the ethanol solution as a surface treating agent.

  Next, the test substrate subjected to surface cleaning in (1) above was immersed in the ethanol solution, subjected to ultrasonic dispersion for 10 minutes, and then air-dried for 24 hours.

(3) Measurement of work function of electrode surface For the test substrate subjected to the surface treatment in (2) above, the work function on the surface of the electrode 43a, 43b of each sample was measured using an atmospheric pressure ultraviolet photoelectron analyzer (AC-manufactured by Riken Keiki Co., Ltd.). 2). Then, the work function value before the surface treatment measured in the above (1) was subtracted from the measured work function value, and the change amount of the work function due to the adsorption of the organic compound was obtained.

(4) Preparation of conductive resin material Bisphenol F-type liquid epoxy resin, 2-phenyl-4-methyldihydroxymethylimidazole, and spherical Ag powder having an average particle diameter of 1.9 μm in a weight ratio of 100: 10: 578 And mixed in a mortar, thereby obtaining a conductive resin material (bonding material).

(5) Measurement of connection resistance value Printing method using the conductive resin material 44 using a metal mask so that the electrodes 43a and 43b of the test substrates subjected to the surface treatment in (2) are electrically connected. And cured by heating at 150 ° C. for 60 minutes.

  Thereafter, the resistance value R between the electrodes 43a and 43b was measured by a four-terminal method.

  In addition, for a test substrate that has not been surface-treated, a conductive resin material (bonding material) is applied and cured by the same method and procedure as described above, and the resistance value R0 between the electrodes 43a and 43b is determined by the four-terminal method. It was measured. And based on the following numerical formula (A), change rate (DELTA) R (%) of the connection resistance value by adsorption | suction of an organic compound was calculated | required.

  ΔR = {(R−R0) / R0} × 100 (A)

  Table 1 shows the composition and measurement results for each sample prepared and measured by the methods (1) to (5). Table 1 also shows samples (sample numbers 17 to 20) that are not subjected to surface treatment for comparison. In Table 1, sample numbers marked with * indicate comparative examples.

  In sample numbers 1 to 4 and 17, the surface layer of the electrode is formed of Sn. When comparing these sample numbers, the sample number 17 that was not subjected to the surface treatment had a resistance value R of 128 mΩ, whereas the sample numbers 1 to 4 had no oxygen atoms in the molecular skeleton and no nitrogen atoms. The surface treatment is performed with an ethanol solution containing the organic compound (hereinafter referred to as “specific organic compound”), and the specific organic compound is adsorbed on the surface layers of the electrodes 43a and 43b. Was -0.05 to -0.16 eV, and the work function was reduced as compared with Sample No. 17, and as a result, the resistance value R was lowered to 94 to 108 mΩ.

  In sample numbers 5 to 8 and 18, the surface layer of the electrode is made of Ag. When comparing these sample numbers, the sample number 18 that was not subjected to the surface treatment had a resistance value R of 59 mΩ, whereas the sample numbers 5 to 8 were made to adsorb specific organic compounds to the surface layers of the electrodes 43a and 43b. Therefore, the amount of change in work function was −0.01 to −0.33 eV, and the work function was reduced as compared with Sample No. 18. As a result, the resistance value R was lowered to 48 to 55 mΩ.

  In sample numbers 9, 10 and 19, the surface layer of the electrode is made of Au. When comparing these sample numbers, the sample number 19 that was not subjected to the surface treatment had a resistance value R of 38 mΩ, while the sample numbers 9 and 10 had the specific organic compound adsorbed on the surface layers of the electrodes 43a and 43b. Therefore, the amount of change in the work function was −0.46 and −0.25 eV, respectively, and the work function was decreased as compared with Sample No. 19, and as a result, the resistance value R was reduced to 33 and 34 mΩ, respectively.

  In sample numbers 11 and 20, the surface layer of the electrode is formed of Sn-37Pb. When comparing these sample numbers, the resistance value R was 165 mΩ in the sample number 20 that was not subjected to the surface treatment, whereas the specific organic compound was adsorbed on the surface layers of the electrodes 43 a and 43 b in the sample number 11. The work function change amount was -0.03 eV, and the work function was reduced as compared with Sample No. 11. As a result, the resistance value R was reduced to 146 mΩ.

  As is apparent from the comparison between sample numbers 1 to 11 and sample numbers 17 to 20, the surface treatment is performed with an ethanol solution containing a specific organic compound, and the surface layer of the electrodes 43a and 43b is adsorbed. It was found that the value R decreases.

  And even if the surface layer of an electrode is another metal material from these results, it is estimated that the same effect is acquired by making a specific organic compound adsorb | suck to an electrode surface.

Sample No. 12 uses an ethanol solution containing triethanolamine [(C ₂ H ₄ OH) ₃ N] having an oxygen atom in the branched skeleton as the surface treatment agent, so that the electrode surface is the surface. Compared with sample No. 17 that was not treated, the work function change amount was +0.05 eV, the work function increased, and the resistance value R increased from 128 mΩ to 130 mΩ. This is presumably because the oxygen atom contained in the molecular skeleton of triethanolamine has a high electron-withdrawing property and exceeds the electron-donating effect of the nitrogen atom.

Sample No. 14 also uses an ethanol solution containing triethanolamine [(C ₂ H ₄ OH) ₃ N] as a surface treating agent, as in Sample No. 12, and therefore for the same reason, Compared with Sample No. 18 that was not surface-treated, the change in work function was +0.21 eV, the work function increased, and the resistance value R increased from 59 mΩ to 65 mΩ.

Sample No. 13 uses an ethanol solution containing decanoic acid [C ₉ H ₁₉ COOH] having an oxygen atom and no nitrogen atom in the branched skeleton as the surface treatment agent. Compared with Sample No. 17 which was not surface-treated, the work function change amount was +0.05 eV, the work function increased, and the resistance value R increased from 128 mΩ to 150 mΩ. This is presumably because the molecular skeleton of decanoic acid does not contain an electron-donating nitrogen atom and also contains an electron-withdrawing oxygen atom.

Similarly to sample number 13, sample number 15 uses decanoic acid [C ₉ H ₁₉ COOH] as the surface treatment agent. For the same reason, sample number 15 is the same as sample number 18 in which the electrode surface was not surface-treated. In comparison, the work function change amount was +0.21 eV, the work function increased, and the resistance value R increased from 59 mΩ to 71 mΩ.

Sample No. 16 also uses decanoic acid [C ₉ H ₁₉ COOH] as a surface treating agent, as in Sample Nos. 13 and 15, and therefore, for the same reason, Sample No. for which the electrode surface was not surface-treated. Compared to 19, the work function change amount was +0.03 eV, the work function increased, and the resistance value R increased from 38 mΩ to 40 mΩ.

  As described above, according to this embodiment, the resistance value R can be reduced by adsorbing the specific organic compound that reduces the work function of the electrode surface to the electrode surface, thereby improving the connection reliability. Was confirmed.

  Examples of the organic compound include an amine compound having no oxygen atom in the molecular skeleton and a nitrogen atom in the molecular skeleton, specifically tetraethylenepentamine, triethylamine, tri-n-butylamine, 1- Aminodecane has also been found to be suitable.

Claims (5)

An electronic component module in which a first electronic component having an external electrode and a second electronic component having an external electrode are electrically connected via a bonding material,
The bonding material is made of a conductive adhesive, and an organic material that lowers the work function of the electrode surface on the surface of at least one of the external electrodes of each of the first and second electronic components. An electronic component module in which a compound is adsorbed.   2. The electronic component module according to claim 1, wherein the organic compound is an amine compound having no oxygen atom and a nitrogen atom in a molecular skeleton.   The electronic component module according to claim 1, wherein the organic compound includes one selected from tetraethylenepentamine, triethylamine, tri-n-butylamine, and 1-aminodecane.   4. The electronic component module according to claim 1, wherein the surface of the external electrode includes one selected from Au, Ag, Sn, or an alloy thereof. 5.   The electronic component module according to claim 1, wherein the conductive adhesive is formed of any one of a conductive resin material and a conductive adhesive sheet.

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