KR20070116673A - Conductive paste composition and printed wiring board - Google Patents

Abstract

Disclosed is a conductive paste composition composed of a phenol resin, a melamine resin, a conductive powder, a solvent and a dihydric alcohol having an ether bond. Also disclosed is a printed wiring board characterized by using such a conductive paste composition. The conductive paste composition enables to form a coating film having a sufficient thickness by a single coating operation. By using this conductive paste composition, a bump having a sufficient height can be formed with a fewer number of coating operations than the conventional conductive paste compositions.

Description

Conductive Paste Composition and Printed Wiring Board {CONDUCTIVE PASTE COMPOSITION AND PRINTED WIRING BOARD}

The present invention relates to a novel conductive paste composition and a printed wiring board. Preferably, the present invention relates to a conductive paste composition particularly suitable for forming electrode bumps used for interlayer connection of a multilayer printed wiring board and a printed wiring board using the same.

Conventionally, the conductive paste composition has been used for many applications in the field of electronics for IC circuits, conductive adhesives, electromagnetic shields, and the like. In particular, recently, a first substrate provided with a conical conductive bump made of conductive paste at a predetermined position on at least one surface and a second substrate provided with a wiring pattern on at least one surface thereof, a surface provided with the conductive bumps and a surface provided with the wiring pattern Opposite to the inside, an insulator layer is disposed between the first substrate and the second substrate to form a laminate, and the laminate is laminated and pressed to penetrate the bumps in the thickness direction of the insulator layer to form a conductive wiring portion. A method for producing a printed wiring board is proposed (Japanese Patent Application Laid-open No. Hei 6-350258).

In addition, the prepreg penetrability is good and cracks are not generated at the time of penetrating and pressing, and bumps with high adhesion between the bumps after the penetrating and the wiring pattern can be produced. A conductive paste comprising a melamine resin, a phenol resin, an epoxy resin, a conductive powder, and a solvent for providing a conductive paste having high connection reliability and having good connection reliability, wherein the softening point of the epoxy resin is 80 ° C. or higher and 130 ° C. or lower. Paste compositions have been proposed (Japanese Patent Laid-Open No. 2002-270033).

In addition, a resin selected from at least one of melamine resin, phenol resin and epoxy resin to provide an adhesive paste composition for printed wiring board interlayer connection which can form bumps without high hardness, cracks and poor connection with wiring patterns. It is proposed to use a conductive paste composition for interlayer connection of a printed wiring board comprising a conductive powder and a dihydric alcohol and / or a trihydric alcohol having a boiling point of 180 ° C. or higher (Japanese Patent Laid-Open No. 2003-77337). .

In addition, Japanese Patent Publication No. 3888400 provides a thermosetting conductive resin composition which can wash an apparatus, a jig and a container with water after screen printing, and includes a water-soluble thermosetting resin, conductive particles, and a dihydric alcohol. A conductive resin composition is known.

A conductive resin composition capable of washing screen plates and the like after printing in accordance with Japanese Patent Application Laid-open No. Hei 9-286924 as water. A water-soluble thermoplastic resin, conductive particles having an average particle diameter of 0.05 to 50 µm, 2 It is known to include alcohols.

Japanese Laid-Open Patent Publication No. 2001-11388 discloses an electrode paste composition for multilayer capacitors comprising a water-soluble resin capable of washing a plate used for printing with water and glycols.

Metal pastes that can be calcined at low temperatures according to Japanese Patent Application Laid-Open No. 2003-331648 and Japanese Patent Laid-Open No. 2004-265826, which include organometallic compounds and alcohol compounds of the Group 3 to 15 metals of the periodic table, preferably glycols. Known metal pastes are known.

In the case of using the conductive paste composition as disclosed in JP 2002-270033 and JP 2003-77337 when forming the electrode bumps by the method as described in JP-A-6-350258. Since the height of the bump which can penetrate an insulating layer is not obtained by one application | coating of a conductive paste composition, it was necessary to carry out application | coating of an electrically conductive paste composition several times and to overprint. Particularly, since the paste is not excessively sharpened in order to avoid bending or cracking of the bump during penetration and pressing of the insulating layer, the bump height is not obtained and the number of overprints tends to increase. there was.

The techniques described in Japanese Patent No. 3588400, Japanese Patent Laid-Open No. 9-286924 and Japanese Patent Laid-Open No. 2001-11388 use water-soluble resins, and also Japanese Patent Laid-Open No. 2003-331648 and Japanese Patent Laid-Open No. 2004 The technique described in -265826 uses a firing type metal paste, which is a non-aqueous non-plastic conductive paste composition like the present invention, and a paste composition in which a sufficient coating thickness is obtained in one coating operation is conventionally known to the present inventors. Was not obtained.

<Patent Document 1> Japanese Patent Application Laid-Open No. 6-350258

<Patent Document 2> Japanese Patent Laid-Open No. 2002-270033

<Patent Document 3> Japanese Unexamined Patent Publication No. 2003-77337

<Patent Document 4> Japanese Patent Publication No. 3588400

<Patent Document 5> Japanese Patent Application Laid-Open No. 9-286924

<Patent Document 6> Japanese Patent Application Laid-Open No. 2001-11388

Patent Document 7: Japanese Unexamined Patent Publication No. 2003-331648

Patent Document 8: Japanese Unexamined Patent Publication No. 2004-265826

Therefore, this invention intends to solve the said subject mainly by using the solvent containing a specific compound.

The electrically conductive paste composition which concerns on this invention consists of a phenol resin, a melamine resin, electroconductive powder, a solvent, and the dihydric alcohol which has an ether bond.

Such a conductive paste composition according to the present invention preferably comprises a divalent alcohol having an ether bond having an ethylenedioxy moiety in its molecular structure.

Such a conductive paste composition according to the present invention preferably includes a divalent alcohol having an ether bond having a hydroxy group at both ends.

Such a conductive paste composition according to the present invention is preferably a divalent alcohol having an ether bond is at least one selected from the group consisting of diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol and hexaethylene glycol. Include.

As for the electrically conductive paste composition which concerns on such this invention as a preferable aspect, when the sum total of the said solvent and the dihydric alcohol which has the said ether bond is 100 mass%, 0.1-50 mass% of the dihydric alcohol which has the said ether bond is contained. It includes.

As a preferred embodiment of the conductive paste composition according to the present invention, the solvent is butyl carbitol acetate, ethyl acetate, butyl acetate, ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, isopropanol, butanol, ter And at least one selected from the group consisting of pinene, texanol, butyl cellosolve acetate, and isophorone.

Such a conductive paste composition according to the present invention further comprises a pigment, preferably a sieving pigment, as a preferred embodiment.

And the printed wiring board which concerns on this invention is characterized by using the said electrically conductive paste composition.

<Conductive Paste Composition>

The electrically conductive paste composition which concerns on this invention consists of a phenol resin, a melamine resin, electroconductive powder, a solvent, and the dihydric alcohol which has an ether bond. Here, "consisting of" does not exclude a conductive paste composition in which components other than the above essential components (that is, a phenol resin, melamine resin, conductive powder, solvent and divalent alcohol having an ether bond) coexist. That is, the electrically conductive paste composition which concerns on this invention contains both the electrically conductive paste composition which consists only of the said essential components, and the electrically conductive paste composition which consists of the said essential component and other components other than these essential components. In addition, "conductive" in the above means that the volume resistivity value is at least 1x10 <^-3> cm * or less.

It is preferable that the electrically conductive paste composition which concerns on this invention is 200-500 Pa.s, especially 300-400 Pa.s. In addition, this viscosity is a thing measured at 10 rpm / min and 25 degreeC with the Malcolm spiral viscometer.

In addition, the conductive paste composition according to the present invention preferably has a thixotropy index of 0.75 to 1.0, particularly 0.8 to 0.95. In addition, this thixotropy index is a thixotropic index calculation log (viscosity value at 5 rpm / viscosity value at 10 rpm) / log from the viscosity of the electrically conductive paste measured by Malcomm spiral viscosity meter at 10 rpm / min, 5 rpm / min, and 25 degreeC. It is a thing calculated by [10 (rpm) / 5 (rpm)]. The thixotropy index is an index showing the property of increasing the apparent viscosity when left standing, and decreasing the apparent viscosity by easy mixing, and making it easier to coat.

(1) phenolic resin

As the phenol resin used in the present invention, any of novolak type and resol type can be used, and in particular, phenol, cresol, xylenol, polyparavinylphenol, p-alkylphenol, chlorophenol, bisphenol A, phenolsulfonic acid and reso Resin etc. which added aldehydes, such as formalin and furfural, and condensed to what has phenolic hydroxyl groups, such as lecin, are mentioned as a preferable resin. Among these, polyparavinyl phenol is especially preferable.

(2) melamine resin

As melamine resin used by this invention, Preferably, methylol melamine and alkylated melamine are mentioned, for example.

(3) conductive powder

As the conductive powder used in the present invention, various conductive fine powders such as silver powder, gold powder, copper powder, nickel powder, platinum powder, palladium powder, solder powder, metal powder such as alloy powder of the above-mentioned metal, etc. can be used. . These electroconductive powders can also be used together 2 or more types. Moreover, electroconductive powder other than metal, for example, carbon powder, can also be used. The conductive powder may be surface treated.

The shape and size of the conductive powder are arbitrary unless it contradicts the object of the present invention. In the present invention, for example, a resinous, scaled, spherical or flake shaped form, and particularly preferably a mixture of scaled and spherical forms can be used. It is preferable that an average particle diameter is 0.5-10 micrometers, especially 1.0-5.0 micrometers.

(4) dihydric alcohols and solvents having ether bonds

The electrically conductive paste composition which concerns on this invention contains a dihydric alcohol which has an ether bond. In the present invention, a dihydric alcohol having an etherylenedioxy moiety in the molecular structure is preferable among the dihydric alcohols having an ether bond, particularly preferably a dihydric alcohol having a hydroxyl group at both ends. As a specific example of such a preferable compound, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, and hexaethylene glycol are mentioned, for example. Among these, triethylene glycol is especially preferable. In the present invention, one kind selected from dihydric alcohols having these ether bonds may be used alone, or two or more kinds may be used in combination.

As a solvent used by this invention, the various organic solvent which can form a paste composition with the said phenol resin, melamine resin, and electroconductive powder can be used, for example. As a preferable specific example of such an organic solvent, for example, butyl carbitol acetate, ethyl acetate, butyl acetate, ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, isopropanol, butanol, terpineol, tec Acidol, butyl cellosolve acetate, isophorone alone, or a mixed solvent thereof.

When the sum total of the divalent alcohol which has a solvent and an ether bond is 100 mass%, the content rate of the dihydric alcohol which has an ether bond is 0.1-50 mass%, Preferably it is 0.5-40 mass%, More preferably, It is 1-30 mass%.

(5) Components (any component) other than the above

The electrically conductive paste composition which concerns on this invention can contain various components as needed. Specific examples of the component that can be included according to such a need include the following pigments, thixotropy-imparting agents, antifoaming agents, dispersing agents, rust inhibitors, reducing agents, and other resin components which can be mixed with the phenol resin and / or melamine resin ( For example, an epoxy resin, an acrylic resin), etc. are mentioned.

Pigment

The electrically conductive paste composition which concerns on this invention can contain various organic or inorganic pigment as needed, and such a pigment | dye aims at reinforcing the coating film of a conductive paste composition, adding a function, improving workability, coloring, and increasing, etc. It becomes possible.

In the present invention, in particular, an extender pigment such as microsilica, calcium carbonate, barium sulfate, magnesium carbonate, alumina, or the like or a mixture thereof can be used.

(6) compounding ratio

The compounding ratio of each component in the electrically conductive paste composition which concerns on this invention is as follows (In addition, the sum total of a resin component means the total amount of a phenol resin and melamine resin here. Resin other than a phenol resin or a melamine resin exists. When used, it means the total amount of each of these resin components).

The total amount of the dihydric alcohol having a solvent and an ether bond is preferably 10 to 100 parts by mass, more preferably 30 to 80 parts by mass, still more preferably 40 to 70 parts by mass with respect to 100 parts by mass in total of the resin component. .

The amount of the conductive powder is preferably 300 to 1100 parts by mass, and more preferably 500 to 900 parts by mass with respect to 100 parts by mass of the resin component.

The amount of the pigment is preferably 1 to 30 parts by mass, more preferably 5 to 25 parts by mass with respect to 100 parts by mass of the resin component.

When the ratio of the phenol resin and the melamine resin in the resin component is expressed by mass ratio, (phenol resin) / (melamine resin) is preferably 10/90 to 90/10, more preferably 30/70 to 70 /. 30, More preferably, it is the range used as 60 / 40-40 / 60.

(7) Use of conductive paste composition

The electrically conductive paste composition which concerns on this invention has favorable electroconductivity, and can print on a board | substrate by well-known printing methods, such as the screen printing method and the metal mask printing method, for example. Therefore, the conductive paste composition according to the present invention can be used in a wide range of fields as in the prior art.

And since the electrically conductive paste composition which concerns on this invention is a thing with thick coating film per one printing job, it can form an electrically conductive layer of sufficient thickness efficiently.

Therefore, since the electrically conductive paste composition which concerns on this invention can form bump of sufficient height with less application | coating frequency | count, for example, only one application | coating frequency | count, it is possible to improve productivity.

<Printed wiring board>

The printed wiring board which concerns on this invention is characterized by using the said electrically conductive paste composition.

Such a printed wiring board according to the present invention, as a preferred embodiment, includes a printed wiring board in which electrical connection between layers is made by bumps formed of the conductive paste composition.

Example

<Examples 1-7>

A phenol resin, melamine resin, silver powder, a sieving pigment, a solvent and a dihydric alcohol having an ether bond were mixed in the mass ratios shown in [Table 1], and thoroughly kneaded with three rolls to prepare a conductive paste composition according to the present invention. . The viscosity and thixotropy index of this electrically conductive paste composition are as Table 1 showing.

Screen (stencil) printing was performed using this electroconductive paste. Specifically, printing is performed using a metal mask plate made of aluminum with a hole of φ 220 µm, and a squeegee made of urethane resin having a hardness of 80 °, while controlling the environment at an ambient temperature of 20 ° C. and a humidity of 50%. To form bumps.

The height and shape of the formed bumps were evaluated. The results are as described in [Table 1].

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7    Furtherance Phenolic resin 50 50 50 50 50 50 50 Melamine resin 50 50 50 50 50 50 50 Silver powder 700 700 700 700 700 700 700 Sieving pigment 10 10 10 10 10 10 10 Butyl Carbitol Acetate 45 45 45 45 45 45 45 Diethylene glycol 7.5 ― ― ― ― ― ― Triethylene glycol ― 3.5 7.5 12.5 ― ― ― Tetraethylene glycol ― ― ― ― 7.5 ― ― Pentaethylene glycol ― ― ― ― ― 7.5 ― Hexaethylene glycol ― ― ― ― ― ― 7.5  Properties Viscosity (Pa · s / 25 ° C) 250 310 370 330 229 226 213 Thixotropy index 0.88 0.85 0.85 0.90 0.80 0.81 0.75 Bump Height (μm) 77 86 85 76 84 75 75 Bump shape Good Good Good Good Good Good Good

<Comparative Examples 1 to 13>

A conductive paste composition (comparative example) was prepared in the same manner as in Example 1 except that the solvent was used in the proportions shown in [Table 2] and [Table 3], and except for the dihydric alcohol having an ether bond. In the same manner, screen printing was performed to evaluate the height and shape of the formed bumps. The results are as described in [Table 2].

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7       Furtherance Phenolic resin 50 50 50 50 50 50 50 Melamine resin 50 50 50 50 50 50 50 Silver powder 700 700 700 700 700 700 700 Sieving pigment 10 10 10 10 10 10 10 Butyl Carbitol Acetate 45 45 45 45 45 45 45 2-butene 1-4 diol ― 7.5 ― ― ― ― ― 1-3 butanediol ― ― 7.5 ― ― ― ― 1-3 propanediol ― ― ― 7.5 ― ― ― 1-5 pentanediol ― ― ― ― 7.5 ― ― 2-3 butanediol ― ― ― ― ― 7.5 ― Propylene glycol ― ― ― ― ― ― 7.5 1-2-2-hexanetriol ― ― ― ― ― ― ― 1-4 butanediol ― ― ― ― ― ― ― 1,2-butanediol ― ― ― ― ― ― ― 3-methyl-1-pentanediol ― ― ― ― ― ― ― 2-methyl-2-pentanediol ― ― ― ― ― ― ― Diethylene glycol monoethyl ether ― ― ― ― ― ― ―  Properties Viscosity (Pa · s / 25 ° C) 250 177 171 223 172 153 162 Thixotropy index 0.50 0.82 0.69 0.92 0.60 0.54 0.69 Bump Height (μm) 58 61 54 63 54 57 56 Bump shape Good Good Good Good Good Good Good

Comparative Example 8 Comparative Example 9 Comparative Example 10 Comparative Example 11 Comparative Example 12 Comparative Example 13        Furtherance Phenolic resin 50 50 50 50 50 50 Melamine resin 50 50 50 50 50 50 Silver powder 700 700 700 700 700 700 Sieving pigment 10 10 10 10 10 10 Butyl Carbitol Acetate 45 45 45 45 45 45 2-butene 1-4 diol ― ― ― ― ― ― 1-3 butanediol ― ― ― ― ― ― 1-3 propanediol ― ― ― ― ― ― 1-5 pentanediol ― ― ― ― ― ― 2-3 butanediol ― ― ― ― ― ― Propylene glycol ― ― ― ― ― ― 1-2-2-hexanetriol 7.5 ― ― ― ― ― 1-4 butanediol ― 7.5 ― ― ― ― 1,2-butanediol ― ― 7.5 ― ― ― 3-methyl-1-pentanediol ― ― ― 7.5 ― ― 2-methyl-2-pentanediol ― ― ― ― 7.5 ― Diethylene glycol monoethyl ether ― ― ― ― ― 7.5  Properties Viscosity (Pa · s / 25 ° C) 210 185 150 158 152 144 Thixotropy index 0.57 0.74 0.60 0.53 0.53 0.62 Bump Height (μm) 62 57 54 53 57 54 Bump shape Good Good Good Good Good Good

<evaluation>

As can be seen from [Table 1], [Table 2] and [Table 3], in Examples 1 to 7 containing a dihydric alcohol having a predetermined ether bond, bumps having a bump height of 75 μm to 86 μm (bump diameter : 220 μm), and the bump height was dramatically increased to 29 to 48% compared to Comparative Example 1 (bump height: 58 μm, bump diameter: 220 μm) without using a divalent alcohol having an ether bond. It can be seen that. The bump shape was also good in the conical shape.

In Comparative Examples 2 to 13 in which monohydric, dihydric or trihydric alcohols were used instead of the dihydric alcohols having ether bonds used in Examples 1 to 7, bump shapes were rounded and bump heights were lowered. Moreover, even if it became high, only the thing which rose to the bump height of about 8.6% was seen.

According to the electrically conductive paste composition of this invention, it is possible to form the coating film of sufficient thickness by one coating operation.

Therefore, bumps of sufficient height can be formed even with fewer application times than before.

Therefore, the number of overprints of the conductive paste composition can be reduced, and the productivity can be improved. Moreover, since the electrically conductive paste composition which concerns on this invention is a thing of non-baking type, it does not need to perform baking operation.

Claims (8)

Consisting of a phenol resin, melamine resin, conductive powder, a solvent and a dihydric alcohol having an ether bond Conductive paste composition. The method of claim 1, The dihydric alcohol having an ether bond has an ethylenedioxy moiety in its molecular structure. Conductive paste composition. The method according to claim 1 or 2, Divalent alcohol having an ether bond has a hydroxyl group at both ends Conductive paste composition. The method according to any one of claims 1 to 3, The dihydric alcohol having an ether bond is at least one member selected from the group consisting of diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, and hexaethylene glycol. Conductive paste composition. The method according to any one of claims 1 to 4, When the sum total of the divalent alcohol which has the said solvent and the said ether bond is 100 mass%, the dihydric alcohol which has the said ether bond is 0.1-50 mass%. Conductive paste composition. The method according to any one of claims 1 to 5, The solvent is butyl carbitol acetate, ethyl acetate, butyl acetate, ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, isopropanol, butanol, terpineol, texanol, butyl cellosolve acetate, iso At least one selected from the group consisting of poron Conductive paste composition. The method according to any one of claims 1 to 6, Further containing pigments, preferably extender pigments Conductive paste composition. Using the electrically conductive paste composition in any one of Claims 1-7. Printed wiring board.