KR100985141B1 - Conductive paste composition and printed wiring board - Google Patents

Abstract

This invention relates to the electrically conductive paste composition which consists of a phenol resin, a melamine resin, an electroconductive powder, a solvent, and a tetravalent or more alcohol, and the printed wiring board using this electrically conductive paste composition. The electrically conductive paste composition by the said invention can form the coating film of sufficient thickness by one application | coating operation | movement, and can form bumps of sufficient height even with less application | coating frequency | count than before.

Conductive paste composition, printed wiring board, phenol resin, melamine resin, alcohol, conductive powder

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.

Background Art Conventionally, conductive paste compositions have been used in various fields, such as for IC circuits, conductive adhesives, and electromagnetic shields, in the field of electronics. In particular, in recent years, 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 are provided with a surface provided with the conductive bump 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 bump in the thickness direction of the insulator layer to form a conductive wiring portion. The manufacturing method of the printed wiring board mentioned is proposed (Japanese Unexamined-Japanese-Patent No. 6-350258).

In the manufacture of a printed wiring board having a good prepreg penetration property, no cracking during penetration and pressing, and a bump with a large adhesive force between the bump after the penetration 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, the conductive paste comprising a high yield and good connection reliability, wherein the softening point of the epoxy resin is 80 ° C. or higher and 130 ° C. or lower. A conductive paste composition for interlayer connection has been proposed (Japanese Patent Laid-Open No. 2002-270033).

Further, at least one of a melamine resin, a phenol resin, and an epoxy resin is selected in order to provide an adhesive paste composition for interlayer connection of a printed wiring board which can form bumps without high hardness, cracks, and poor connection with wiring patterns. And conductive powders and bivalent alcohols having a boiling point of 180 ° C. or higher and / or trihydric alcohols are proposed to use a conductive paste composition for interlayer connection of a printed wiring board (JP-A-2003-77337). .

Further, Japanese Patent Publication No. 3588400 provides an example of 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. Characteristic conductive resin compositions are known.

As in JP-A-9-286924, similarly to JP-A-3588400, as a conductive resin composition which can wash screen plates and the like after printing with water, water-soluble thermoplastic resins, conductive particles having an average particle diameter of 0.05 to 50 µm. And dihydric alcohols are known.

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

According to Japanese Patent Laid-Open Publication No. 2003-331648 and Japanese Patent Laid-Open Publication No. 2004-265826, as a metal paste which can be baked at low temperature, organometallic compounds and alcohol compounds of Group 3 to 15 metals of the periodic table, preferably glycols Metal pastes containing are known.

In the case of forming the electrode bumps by the method described in JP-A-6-350258, in the case of using the conductive paste composition as disclosed in JP-A-2002-270033 and JP-A-2003-77337 Since the bump height enough to penetrate the insulating layer cannot be obtained by one coating operation of the conductive paste composition, it is necessary to apply the conductive paste composition several times and overprint it. In particular, in order to avoid bump bending and cracking during the penetration of the insulating layer and at the time of pressing, since the paste which does not sharpen the bump shape is used, the bump height cannot be obtained and the number of overprints tends to increase.

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 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, and the present inventors know that a paste composition capable of obtaining a sufficient coating thickness in one coating operation while being a non-aqueous non-plastic conductive paste composition like the present invention. As long as it has not been obtained in the past.

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

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

<Patent Document 3> Japanese Laid-Open 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 Laid-Open Patent Publication No. 2003-331648

<Patent Document 8> Japanese Patent Application Laid-Open No. 2004-265826

The present invention aims to solve the above problems by forming a conductive paste composition with a specific component.

Therefore, the electrically conductive paste composition which concerns on this invention consists of a phenol resin, a melamine resin, an electroconductive powder, a solvent, and a tetravalent or more alcohol.

Such a conductive paste composition according to the present invention includes, as a preferred embodiment, at least one selected from the group consisting of tetravalent, xylitol and sorbitol.

Such a conductive paste composition according to the present invention preferably comprises at least one selected from the group consisting of D-thritol, L-thritol and meso-erythritol.

Such a conductive paste composition according to the present invention includes, as a preferred embodiment, the aforementioned tetrahydric or higher alcohol in a solution state.

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

And the printed wiring board which concerns on such this invention uses 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 tetrahydric or more alcohol. Here, "consisting of" does not exclude conductive paste compositions in which other components other than the essential components (that is, phenol resin, melamine resin, conductive powder, solvent and tetravalent or higher alcohol) 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, said "conductivity" means that a volume resistance value is at least 1x10 <^-3> cm * or less.

It is preferable that the electrically conductive paste composition which concerns on this invention is 200-600 Pa.s, especially 300-550 Pa.s. In addition, this viscosity is a thing measured at 10 rpm / min and 25 degreeC with the Malcolm spiral viscometer.

The thixotropic index of the conductive paste composition according to the present invention is preferably 0.65 to 1.0, particularly 0.70 to 0.95. In addition, this thixotropy index is a thixotropic index calculation log (viscosity value at the viscosity value / 10 rpm at 5 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. When calculated in [10 (rpm) / 5 (rpm)]. The thixotropy index is an index indicating the property of increasing the apparent viscosity when left standing, and decreasing the apparent viscosity when it is strongly mixed, thereby making it easier to coat.

(1) phenolic resin

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

(2) melamine resin

As a melamine resin used by this invention, 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, for example, silver powder, gold powder, copper powder, nickel powder, platinum powder, palladium powder, solder powder, metal powder such as alloy powder of the above metal, etc. can be used. have. 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 is arbitrary unless it contradicts the purpose 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) solvent

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, texanol And butyl cellosolve acetate, isophorone alone, or a mixed solvent thereof.

(5) tetrahydric or higher alcohol

As a tetrahydric or more alcohol used by this invention, Preferably, tetrahydric alcohols, such as a pentitol, pentahydric alcohols, such as xylitol, and hexavalent alcohols, such as sorbitol, can be used. These tetrahydric or more alcohols can be used individually or in combination of 2 or more types, respectively.

Tracel

In the present invention, all of D-thritol, L-thritol and meso-erythritol alone or mixture thereof can be used. Traceol is equivalent to sugar alcohol derived from threose, and can be obtained, for example, by reducing threose with sodium amalgam.

In the present invention, any tracer obtained by any method can be used as long as it does not contradict the object of the present invention.

Xylitol

Xylitol is a sugar alcohol corresponding to D-xylose. Such xylose can be obtained, for example, by reducing D-xylose to pressurized hydrogen using sodium amalgam or nickel as a catalyst. There are two types of crystals from alcohols: metastable tetragonal and stable monoclinic.

In the present invention, any xylitol obtained by any method can be used as long as it does not contradict the object of the present invention.

Sorbitol

Sorbitol is equivalent to the sugar alcohol of glucose. Such sorbitol can be industrially obtained by, for example, reducing D-glucose to pressurized hydrogen using sodium amalgam, platinum or nickel as a catalyst, and electrolytically reducing D-glucose.

In the present invention, any sorbitol obtained by any method can be used as long as it does not contradict the object of the present invention.

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

The electrically conductive paste composition by this invention can contain various components as needed. Specific examples of components that can be included according to such needs include pigments, thixotropy-imparting agents, defoamers, dispersants, rust inhibitors, reducing agents, and other resin components (e.g. epoxy) that can be mixed with the phenol resins and / or melamine resins. Resin, acrylic resin), and the like.

Pigment

The conductive paste composition according to the present invention may contain various organic or inorganic pigments, if necessary, so that the coating layer reinforcement, functional addition, workability improvement, coloring and increase of the conductive paste composition can be achieved by such a pigment. do.

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.

(7) compounding ratio

The compounding ratio of each component in the electrically conductive paste composition by this invention is as follows (In addition, in the following, the sum total of a resin component means sum total measurement of a phenol resin and a melamine resin. However, resin other than a phenol resin or a melamine resin is used. When present, it means the total amount of each of these resin components).

The amount of the solvent is preferably 10 to 100 parts by mass, more preferably 20 to 80 parts by mass, still more preferably 30 to 65 parts by mass relative to 100 parts by mass of the total of the resin components.

The quantity of electroconductive powder becomes like this. Preferably it is 300-1100 mass parts with respect to 100 mass parts of resin components, More preferably, it is 500-900 mass parts.

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

The ratio of the phenol resin and the melamine resin in the resin component is represented by the mass ratio, and (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.

The compounding quantity of a tetravalent or more alcohol becomes like this. Preferably it is 0.05-10 mass parts, More preferably, it is 0.25-5 mass parts with respect to 100 mass parts of resin components.

(8) Use of Conductive Paste Composition

The electrically conductive paste composition by 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. Accordingly, 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 thick in one printing operation, an electrically conductive layer of sufficient thickness can be formed efficiently.

Accordingly, the conductive paste composition according to the present invention can form bumps with a sufficient height even with fewer application times, for example, only one application time, so that productivity can be improved.

<Printed wiring board>

The printed wiring board which concerns on this invention used the said electrically conductive paste composition, It is characterized by the above-mentioned.

The 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 from the conductive paste composition.

Example

<Examples A1 to A5 and Comparative Example A1>

The following phenol resin, melamine resin, silver powder, extender pigments, solvents, and pentitol were mixed in the mass ratios shown in Table 1, and thoroughly kneaded with three rolls to prepare an electrically 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, using a metal mask plate made of aluminum with a hole of φ 220 μm, using a urethane resin squeegee having a hardness of 80 °, printing is performed while controlling the environment at an ambient temperature of 20 ° C. and a humidity of 50%, and bumps. Was formed.

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

In addition, in Table 1, "erythritol" of Example A4 means "mixture of D-thritol, L-thritol, and meso-erythritol", and "DL-thritol" of Example A5 means "D-tray". Mixture of tall and L-thritol ”.

Comparative example
A1 Example
A1 Example
A2 Example
A3 Example
A4 Example
A5 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 D-Treitol - 2.3 - - - - L-Treitol - - 2.3 - - - Meso-erythritol - - - 2.3 - - Erythritol ^{* 1} - - - - 2.3 - DL-Treitol ^{* 2} - - - - - 2.3 Properties Viscosity (Pas / 25 ° C) 250 399 407 317 262 507 Thixotropy index 0.50 0.77 0.80 0.73 0.73 0.79 Bump Height (μm) 58 107 99 89 95 105 Bump shape Good Good Good Good Good Good

* 1: Mixture of D-thritol, L-thritol and meso-erythritol

* 2: Mixture of D-thritol and L-thritol

<Evaluation>

As apparent from Table 1 above, in Examples containing pentitol, bumps having a bump height of 89 µm to 107 µm (bum diameter: 220 µm) can be formed, and Comparative Example 1 (bump height without using the compound) : 58 micrometers, bump diameter: 220 micrometers) It turns out that bump height increases dramatically with 53-84%. The bump shape was also good in the shape of a cone.

<Example B1 and Comparative Example B1>

The following phenol resin, melamine resin, silver powder, extender pigment, solvent, and xylitol were mixed in the mass ratios shown in Table 2, and thoroughly kneaded with three rolls to prepare an electrically conductive paste composition according to the present invention. The viscosity and thixotropy index of this electrically conductive paste composition are as Table 2 showing.

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

The height and shape of the formed bumps were evaluated. The results are as described in Table 2.

Comparative Example B1 Example B1 Furtherance Phenolic resin 50 50 Melamine resin 50 50 Silver powder 700 700 Sieving pigment 10 10 Butyl Carbitol Acetate 45 45 Xylitol - 2.3 Properties Viscosity (Pas / 25 ° C) 250 287 Thixotropy index 0.50 0.70 Bump Height (μm) 58 71 Bump shape Good Good

<Evaluation>

As apparent from Table 2, in Example B1 containing xylitol, bumps having a bump height of 71 μm (bum diameter: 220 μm) can be formed, and Comparative Example B1 (bum height: 58 μm, bump diameter: It can be seen that the bump height is dramatically increased to 22% as compared with 220 µm). The bump shape was also good in the shape of a cone.

<Example C1 and Comparative Example C1>

The following phenol resin, melamine resin, silver powder, extender pigment, solvent, and sorbitol were mixed in the mass ratios shown in Table 3, and thoroughly kneaded with three rolls to prepare an electrically conductive paste composition according to the present invention. The viscosity and thixotropy index of this electrically conductive paste composition are as Table 3 showing.

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

The height and shape of the formed bumps were evaluated. The results are as described in Table 3.

Comparative Example C1 Example C1 Furtherance Phenolic resin 50 50 Melamine resin 50 50 Silver powder 700 700 Sieving pigment 10 10 Butyl Carbitol Acetate 45 45 Sorbitol - 2.3 Properties Viscosity (Pas / 25 ° C) 250 264 Thixotropy index 0.50 0.60 Bump Height (μm) 58 69 Bump shape Good Good

<Evaluation>

As apparent from Table 3, in Example C1 containing sorbitol, bumps having a bump height of 69 µm (bum diameter: 220 µm) can be formed, and Comparative Example C1 (bum height: 58 µm, bump diameter: 220 µm) It can be seen that the bump height is dramatically increased to 19% as compared to). The bump shape was also good in the shape of a cone.

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 non-baking type, it is not necessary to perform baking operation.

Claims (7)

Phenolic resin, melamine resin, conductive powder, solvent and tetravalent or more alcohol Conductive paste composition. The method of claim 1, The tetrahydric or higher alcohol is at least one member selected from the group consisting of pentitol, xylitol and sorbitol Conductive paste composition. The method of claim 2, The tracer is at least one member selected from the group consisting of D-thritol, L-thritol and meso-erythritol Conductive paste composition. The method of claim 1, Containing the above-mentioned tetrahydric alcohol in a solution state Conductive paste composition. The method of claim 1, Containing more pigment Conductive paste composition. The method of claim 5, The pigment is a extender pigment Conductive paste composition. The printed wiring board using the electrically conductive paste composition of Claim 1.