JP2009065009A - Multilayer wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer wiring board which can decrease a resistance value of a via hole to a large extent, which is excellent in moisture absorption thermal resistance, connection reliability, conductor adhesion strength, and manufacturing process aptitude, and which has a small environmental load. <P>SOLUTION: In multilayer wiring boards 200a and 200b constituted by laminating a wiring substrate composed of an insulating base comprising a conductor pattern 20 and a via 40 by thermal fusion, a conductive paste composition forming the via is a thermoplastic resin composition in which conductive powder and a binder component are included at a predetermined mass ratio, the conductive powder is a non-lead solder particle having a melting point of 130°C or more and 240°C or less (a first alloy particle) and at least one or more kinds selected from Au, Ag, and Cu (a second metal particle), the first alloy particle and the second metal particle are present at a predetermined mass ratio, and the binder component has Tg lower than the melting point of the first alloy particle and a flow beginning temperature of 260°C or more. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a multilayer wiring board, and more particularly to a multilayer wiring board formed by laminating a plurality of wiring boards formed with vias filled with a conductive paste composition.

  Advances in the highly information-oriented society have led to faster information processing in electronic devices (higher operating frequency) and wider frequency bands for information communications (broadband). There is a need for a wiring board. Further, the wiring board material is required to have a low relative dielectric constant and dielectric loss tangent.

  As this high-density multilayer wiring board, a buildup multilayer board in which buildup layers made of a photosensitive epoxy resin are successively stacked above and below a core layer made of a glass epoxy board has been proposed since the 1990s. This build-up multilayer board is used in many electronic devices today because fine wiring is easier compared to conventional multilayer boards.

  However, in the build-up multilayer wiring board, the through-hole diameter and wiring interval of the core substrate are different from the via diameter and wiring interval of the build-up layer stacked above and below the core layer in order to ensure the insulation reliability of the substrate. In addition, there is a problem that the via wiring for connecting each layer is formed by copper plating, and the via cannot be formed on the via in the manufacturing process. Therefore, in the build-up multilayer wiring board, a limit has begun to appear in order to cope with the further higher density demanded in recent years.

  As a solution to these problems, a coreless all-layer IVH (Intermediate Via Hole) substrate that has a high degree of freedom in wiring design and excellent transmission characteristics has recently attracted attention. Via wiring for connecting each layer in the coreless all-layer IVH substrate is formed of a conductive paste composition. Therefore, it is possible to form a via-on-via structure and a pad-on-via structure in which a via is formed on the via, and sufficiently meet the recent demand for higher density.

  Here, the greatest point in improving the performance (high density, high reliability) of the multilayer wiring board is made of a conductive paste composition formed in the thickness direction of each layer in addition to the above-described wiring structure. The connection reliability between the via wiring and the conductor pattern made of the copper foil formed on the surface of each layer is sufficiently ensured when multilayered.

  As a conventional technique related to a multilayer wiring board, Patent Document 1 discloses that a defect in the conventional build-up multilayer wiring board is solved, and the degree of freedom in wiring design is high, and a stacked via structure can be realized. A multilayer wiring board having an all-layer IVH structure suitable for signal transmission has been proposed. According to the description in Patent Document 1, a sheet substrate material in which an aramid nonwoven fabric is impregnated with an epoxy resin which is a thermosetting resin is used, and a through hole is formed in the sheet substrate material. The through holes are filled with a conductive paste composed of metal particles, a binder resin such as epoxy, and a solvent, and then dried and solidified. And the double-sided copper clad board which hardened the conductive paste is produced by carrying out the hot press of the copper foil on both surfaces of this board | substrate material. This double-sided copper-clad board is etched to form a double-sided circuit board. Thereafter, the sheet substrate material (prepreg) is arranged on both sides of the double-sided circuit board, and a copper foil is further arranged on the outside thereof, followed by hot pressing, thereby providing a multilayer wiring board having a four-layer inner via hole structure. Is formed.

  Non-Patent Document 1 discloses that a rigid single-sided copper-clad laminate made of a glass cloth epoxy substrate is used as an example of a multilayer wiring board that has an all-layer IVH structure and can be multilayered by batch lamination. An all-layer IVH wiring board manufactured by manufacturing a single-sided circuit board having a pattern and via holes, applying an adhesive made of a thermosetting resin to the opposite surface on which the wiring pattern is formed, and performing batch lamination pressing is described. Has been. The following items are listed as characteristics of this method. First, a stacked via structure or a pad-on-via structure can be easily realized. In addition, the via land diameter can be reduced because the via position is less likely to change during the laminating press as compared with the above-described method of via-processing the prepreg. Then, by adopting the collective multilayer construction method, a high yield can be expected by laminating and pressing only the substrates having no defects. In addition to the extremely simple process, the delivery time can be greatly shortened by producing each layer in parallel.

  In Non-Patent Document 2, an adhesive layer based on a thermosetting resin and its cover film are provided in advance on the opposite side of the copper-clad surface of a single-sided copper-clad laminate made of thermosetting resin, and copper is etched. The document describes that after the circuit formation and via formation with the conductive paste are completed, the cover film is removed and then laminated at once.

  In Patent Document 2, as an example of a multilayer wiring board having an all-layer IVH structure and capable of being multilayered by batch lamination without using an adhesive, it is for batch multilayer made of a thermoplastic resin mixture made of polyaryl ketone and polyetherimide. There is a description of an insulating substrate. This is because the insulating substrate before batch lamination is made amorphous, and heat fusion occurs between the layers at the time of batch lamination press above the glass transition temperature of the resin mixture. To do.

  Patent Document 3 discloses a method of manufacturing a multilayer printed wiring board in which a plurality of IVH substrates are stacked with an insulator layer interposed therebetween, and the inner layer portion of the via hole is previously closed with a resin and is identical to the via hole of the insulator layer. A method for manufacturing a multilayer printed wiring board is described, in which a conductive paste is disposed through the coordinates, and the inner lands of each via hole are connected by a conductive paste during lamination. According to this method, the conductive paste does not enter the empty copper of each via hole during lamination, and a reliable connection between the conductive paste and the inner land is obtained.

  Patent Document 4 includes a first wiring board having a signal wiring having a first cross-sectional area and having a power supply layer on both surfaces, and a high-density signal wiring having a second cross-sectional area smaller than the first cross-sectional area. And a pair of second wiring boards each having a power supply on the surface opposite to the mounting surface. The power supply / ground layer of the first wiring board and the power supply / ground layer of the second wiring board are placed at predetermined positions so that the first wiring board is sandwiched between the pair of second wiring boards. It is described that they are bonded together with an adhesive insulating sheet having

Patent Document 5 describes a wiring board including an insulating substrate, a conductor wiring layer, and a via-hole conductor. As the conductive paste for forming the via-hole conductor, in the examples, a conductive paste containing silver-coated copper powder, a Pb—Sn alloy, an epoxy resin, and a solvent is described. In the present invention, the molten tin component reacts with the copper component by heating during the production of the wiring board, and an intermetallic compound such as Cu ₃ Sn is generated. Further, it is described that the intermetallic compound can firmly bond the copper powder or between the copper powder and the conductor wiring layer to improve heat resistance and conductivity.

  Patent Document 6 describes a conductive composition filled in a via hole provided in an insulating base material in a printed circuit board. This conductive composition is made of an alloy of tin and silver, and this tin forms a solid phase diffusion phase with a metal that forms a conductor pattern in a printed circuit board, and is electrically connected. In this case, it is described that since the electrical connection between the conductor patterns is not performed by contact conduction, the interlayer connection resistance value hardly changes and the reliability of the interlayer connection can be prevented from being lowered.

In Patent Document 7, a metal containing at least copper having a melting point higher than the fusion temperature of the base material, a metal that can be alloyed with the conductor pattern and having a melting point lower than the fusion temperature of the base material, and a base It is described that a binder resin that melts at a temperature lower than the fusing temperature of the material is filled in the via hole to form a multilayer wiring board.
Japanese Patent Laid-Open No. 7-176846 Ryo Enomoto, “All-Layer IVH Wiring Board by Batch Lamination”, Journal of Japan Institute of Electronics Packaging, Japan Institute of Electronics Packaging, November 2000, Vol. 3, No. 7, p. 544-547 Shuji Maeda, 3 others, “Batch multilayer wiring board material and corresponding process”, MES 2004 14th Microelectronics Thesis, Japan Institute of Electronics Packaging, October 14, 2004, p. 341-344 Japanese Patent No. 3514647 JP 2004-28889A Japanese Patent Laying-Open No. 2005-116811 Japanese Patent No. 3187373 Japanese Patent No. 3473601 JP 2006-165508 A

  However, the multilayer wiring board construction method described in Patent Document 1 is the same sequential construction method as the build-up construction method. In addition, since a single material such as a prepreg has the two functions of an interlayer insulating layer and an adhesive layer, there is a problem that the melting and fluid deformation during the multilayering are large and the positional accuracy in the stacking direction varies. Accordingly, it is difficult to reduce the via land diameter from the viewpoint of via position accuracy, and it is difficult to use the via land as a mother board or a module substrate. Moreover, the conductive paste used in Patent Document 1 was a pressure contact type conductive paste. The pressure-contact type conductive paste is intended to conduct electricity by contact of metal particles due to solvent volatilization, resin curing shrinkage, and lamination pressure. However, connection reliability may be inferior to metal diffusion type conductive paste. It was.

  In addition, the multilayer wiring boards described in Non-Patent Documents 1 and 2 have an all-layer IVH structure and can be multilayered by batch lamination. However, in order to carry out batch lamination, an adhesive made of a thermosetting resin is used. It is necessary to use an agent. For this reason, it is difficult to control the flow hardening characteristics of the adhesive, or the adhesive intervenes, the linear expansion coefficient in the Z direction of the substrate becomes non-uniform, and the connection reliability between the electrical layers is impaired. There was a problem. Further, the conductive paste used in Non-Patent Documents 1 and 2 was a pressure contact type conductive paste.

  In addition, since the multilayer wiring board described in Patent Document 2 is composed of a new material as an insulating base material, it is necessary to readjust the process when performing batch stacking or component mounting. It took. Moreover, the conductive paste used in Patent Document 2 was a pressure contact type conductive paste.

  In addition, in the method for manufacturing a multilayer printed wiring board described in Patent Document 3, when forming plated through holes and connecting the plated through holes, the conductive paste is prevented from entering the plated through holes. Thus, the object is to physically and reliably connect the conductive paste and the plated through hole.

  In addition, the multi-layer wiring circuit board described in Patent Document 4 separately includes a high-density wiring board for mounting LSIs and the like and a high-frequency wiring board having signal wiring necessary for high-speed transmission. The object is to prepare and affix them to produce a multilayer wiring circuit board suitable for both high frequency and high density.

  Therefore, the inventions described in Patent Literature 1, Patent Literature 2, Non-Patent Literature 1, Non-Patent Literature 2, Patent Literature 3 and Patent Literature 4 are not related to a connection technique between vias in a multilayer wiring board, It was not intended to improve the performance of the multilayer wiring board by, for example, metal diffusion bonding between the metal particles therein. For this reason, there existed a subject in the point of reduction of the resistance value of via | veer, moisture absorption heat resistance, connection reliability, and conductor adhesive strength.

  Moreover, the conductive paste described in Patent Document 5 uses a solder containing lead as solder. Such a lead-containing solder has a problem because when the wiring board using the lead-containing solder is discarded, the lead may be eluted from the substrate and the groundwater may be contaminated, and the environmental load is large. The electronic component was reversing in the direction of making Pb free.

  In addition, the invention described in Patent Document 6 aims to improve the performance of the multilayer wiring board by, for example, metal diffusion bonding between the metal particles in the via hole, but there is no binder resin, It is necessary to use a special apparatus for filling the via hole, and it is difficult to fill the via hole with a good yield with a normal printing means, and it is necessary to adopt a special printing method.

  The paste described in Patent Document 7 is a paste containing resin while using lead-free solder. However, from the standpoint of producing a higher performance wiring substrate, the conductive paste composition in the via is highly metal diffusion bonded and the resistance value of the via is required to be very low. The multilayer wiring board described in Document 7 has room for improvement. That is, in Patent Document 7, a metal containing copper having a melting point higher than the lamination temperature, a metal containing Sn having a melting point lower than the lamination temperature, and a binder resin that melts below the lamination temperature are filled in the via hole. In the case of a metal containing Sn having a melting point lower than the laminating temperature or a binder resin that melts below the laminating temperature, the metal containing Sn flows out from the via portion before each layer is heat-sealed during laminating. Alloying was sometimes inhibited.

  Therefore, the present invention provides a multilayer wiring board that can extremely reduce the resistance value of a via hole, is excellent in moisture absorption heat resistance, connection reliability, conductor adhesive strength, and manufacturing process suitability, and has a low environmental load. Let it be an issue.

  The present invention will be described below. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiments.

  The first aspect of the present invention includes an insulating base material (10) made of a thermoplastic resin composition, and a conductor pattern (20) provided on the insulating base material, and the conductive base material is filled in the insulating base material. The wiring board (100a) formed with the formed via (40) is formed by superimposing a plurality of the wiring boards (100a) or other than a thermoplastic resin composition different from the wiring board (100a). A multilayer wiring board that is alternately laminated with a wiring board (300) and is laminated by heat fusion or sequentially laminated, wherein the conductive paste composition includes a conductive powder and a binder component, The mass ratio of the conductive powder and the binder component is 90/10 or more and less than 98/2, the conductive powder is composed of the first alloy particles and the second metal particles, and the first alloy particles are 130 ° C. Above 240 ° C A lead-free solder particle having a point, and the second metal particle is at least one selected from the group consisting of Au, Ag, and Cu, and the mass of the first alloy particle and the second metal particle A multilayer wiring board having a ratio of 76/24 or more and less than 90/10, wherein the binder component is a thermoplastic resin composition having a Tg of less than the melting point of the first alloy particles and a flow initiation temperature of 260 ° C. or more. 200a, 200b).

  According to the first aspect of the present invention, by forming the multilayer wiring board by combining the conductive paste composition having the above configuration and the insulating base material made of the thermoplastic resin composition, the solder component of the solder particles can be reduced. High metal diffusion bonding is performed between the two metal particles and the metal forming the conductor pattern. In particular, by using a thermoplastic resin composition having a Tg less than the melting point of the first alloy particles and a flow starting temperature of 260 ° C. or higher as the binder component, the binder component is soft when the first alloy particles are dissolved. Therefore, the solder component (first alloy particles) forms the second metal particles and the conductor pattern because the binder component does not flow out at the lamination temperature when the multilayer wiring board is manufactured and does not hinder metal diffusion bonding. High metal diffusion bonding can be performed between metals. Thereby, the resistance value of the via of the multilayer wiring board can be made extremely small, and the multilayer wiring board can be made excellent in moisture absorption heat resistance, connection reliability, and conductor adhesive strength. Here, “metal diffusion bonding” means that tin in the lead-free solder particles forms the second metal particles and / or conductor pattern when the melting point of the alloy made of lead-free solder particles is exceeded. It means that it diffuses into a metal and forms a new alloy. In addition, the conductive paste composition used in the multilayer wiring board of the present invention can be filled in via holes by a normal printing technique, and since it does not contain lead, it has a low environmental burden and is preferable.

  In the first aspect of the present invention, the binder component is preferably at least one selected from polysulfone resins and polyethersulfone resins. By using such a binder component, metal diffusion bonding can be further promoted.

  In the first aspect of the present invention, the average particle diameter of the first alloy particles and the second metal particles is preferably 10 μm or less, and the difference in average particle diameter is preferably 2 μm or less. By making the first alloy particles have such a particle size, it becomes easy to fill the via holes with the conductive paste composition, and metal diffusion tends to occur. Moreover, the effect which adjusts the viscosity of the electrically conductive paste composition at the time of carrying out heating lamination | stacking of a board | substrate by using a 2nd metal particle as such a particle size becomes favorable. Further, by making the average particle size difference between the first alloy particles and the second metal particles as close as possible, metal diffusion bonding can be easily generated.

  In the first invention, the first alloy particles are Sn, Sn—Ag, Sn—Cu, Sn—Sb, Sn—Bi, Sn—In, Sn—Zn, Sn—Ag—Cu, Sn—Ag—. One or more kinds selected from the group consisting of In, Sn—Ag—In—Bi, Sn—Zn—Bi, Sn—Ag—Bi, Sn—Ag—Cu—Bi, and Sn—Ag—Cu—Sb Lead solder particles are preferred. These non-lead solder particles are reliable in the effect of metal diffusion bonding of tin.

  In the first aspect of the present invention, the storage elastic modulus of the thermoplastic resin composition constituting the insulating substrate at the melting point of the lead-free solder particles is preferably 10 MPa or more and less than 7 GPa. By using a thermoplastic resin composition having such a storage elastic modulus, the thermoplastic resin composition has a certain degree of flexibility at the melting point of the lead-free solder particles and retains a certain degree of elasticity without melting. I am letting. Thereby, the conductive paste composition in the via and the thermoplastic resin composition on the side surface of the via hole can be compatible with each other. Moreover, metal diffusion bonding can be promoted.

  In the first present invention, the thermoplastic resin composition constituting the insulating substrate (10) is a polyaryl ketone resin and an amorphous polyetherimide resin having a crystal melting peak temperature (Tm) of 260 ° C. or higher. A mixed composition is preferred. By using such a mixed composition, it can be set as the thermoplastic resin composition provided with the preferable storage elastic modulus mentioned above.

  In the first aspect of the present invention, the wiring base plate (300) made of other than the thermoplastic resin is a glass epoxy base plate (FR4 substrate), a two-layer polyimide substrate, a pseudo two-layer polyimide substrate, a three-layer polyimide substrate, a liquid crystal polymer (LCP). It is preferably one or more wiring substrates selected from the group consisting of a substrate and a low temperature fired ceramic (TLCC) substrate. A wiring board made of a material other than these exemplified thermoplastic resin compositions can be laminated with a wiring board provided with an insulating base made of a thermoplastic resin composition alternately, and can be satisfactorily laminated by thermal fusion.

  In the first aspect of the present invention, it is preferable that the batch lamination or sequential lamination by thermal fusion of the wiring boards is performed at a temperature of 150 ° C. or more and less than 260 ° C. and a pressure of 3 MPa or more and less than 8 MPa. By performing heat fusion lamination under such conditions, metal diffusion bonding is performed between the first alloy particles and the second metal particles and / or between the first alloy particles and the metal forming the conductor pattern. It can be formed effectively.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

  FIG. 1 shows an outline of a method for manufacturing multilayer wiring boards 200a and 200b of the present invention. As shown in FIGS. 1A to 1G, a multilayer wiring board 200a of the present invention includes an insulating base material 10 made of a thermoplastic resin composition, and a conductor pattern 20 provided on the insulating base material. A plurality of wiring boards 100a formed by forming vias 40 filled with a conductive paste composition on the insulating base material 10 are laminated and manufactured by heat sealing.

  In addition, as shown in FIGS. 1H to 1L, a multilayer wiring board 200b according to another embodiment of the present invention includes an insulating base material 10 made of a thermoplastic resin, and a conductive paste is provided on the insulating base material 10. The wiring board 100b formed with the via 40 filled with the composition is alternately overlapped with the wiring board 300 made of a material other than the thermoplastic resin composition different from the wiring board 100b, and is laminated by thermal fusion. Manufactured. Hereinafter, each component of the multilayer wiring boards 200a and 200b of the present invention will be described in order.

<Insulating base material 10 made of thermoplastic resin composition>
The thermoplastic resin composition forming the insulating substrate 10 made of a thermoplastic resin composition is a mixture of a polyaryl ketone resin and an amorphous polyetherimide resin having a crystal melting peak temperature (Tm) of 260 ° C. or higher. It is preferable to use a composition. Note that the polyaryl ketone resin and the amorphous polyetherimide resin are compatible systems, and these mixed compositions have one crystal melting peak temperature. That is, in the above, it means that one crystal melting temperature of the mixed composition of the polyaryl ketone resin and the amorphous polyetherimide resin is 260 ° C. or higher.

  This polyaryl ketone resin is a thermoplastic resin having an aromatic nucleus bond, an ether bond and a ketone bond in its structural unit, and representative examples include polyether ketone, polyether ether ketone, polyether ketone ketone, etc. Of these, polyetheretherketone is preferred. Polyether ether ketone is commercially available as “PEEK151G”, “PEEK381G”, “PEEK450G” (all are trade names of VICTREX), and the like.

  The amorphous polyetherimide resin is an amorphous thermoplastic resin containing an aromatic nucleus bond, an ether bond and an imide bond in the structural unit, and is not particularly limited. Polyetherimide is commercially available as “Ultem CRS 5001”, “Ultem 1000” (both are trade names of General Electric).

  The mixing ratio of the polyaryl ketone resin and the amorphous polyetherimide resin is 30% by mass or more and 70% by mass or less of the polyaryl ketone resin in consideration of adhesion to the other wiring boards 100a and 300 to be laminated. It is preferable to use a mixed composition containing an amorphous polyetherimide resin and inevitable impurities. Here, the reason why the content of the polyaryl ketone resin is limited to 30% by mass or more and 70% by mass or less is that when the content of the polyaryl ketone resin is too high, the crystallinity of the thermoplastic resin composition is high. This is because the lamination property at the time of multilayering is lowered, and if the content of the polyaryl ketone resin is too low, the crystallinity itself of the thermoplastic resin composition as a whole is lowered, and the crystal melting peak temperature is 260 ° C. It is because reflow heat resistance falls even if it is above.

  This thermoplastic resin composition may contain an inorganic filler. There is no restriction | limiting in particular as an inorganic filler, Any well-known thing can be used. Examples thereof include talc, mica, mica, glass flake, boron nitride (BN), plate-like carbon cal, plate-like aluminum hydroxide, plate-like silica, and plate-like potassium titanate. These may be added singly or in combination of two or more. In particular, a scale-like inorganic filler having an average particle size of 15 μm or less and an aspect ratio (particle size / thickness) of 30 or more can keep the linear expansion coefficient ratio in the plane direction and the thickness direction low, and the thermal shock cycle test. This is preferable because generation of cracks in the substrate at the time can be suppressed.

  The added amount of the inorganic filler is preferably 20 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin. This is because if the amount of the inorganic filler added is too large, a problem of poor dispersion of the inorganic filler occurs, and the linear expansion coefficient tends to vary or the strength tends to decrease. In addition, if the amount of the inorganic filler added is too small, the effect of reducing the linear expansion coefficient and improving the dimensional stability is small, which is caused by the difference in the linear expansion coefficient with the other wiring substrate 300 or the conductive pattern 20 in the reflow process. This is because internal stress is generated, and the substrate is warped and twisted.

  In addition, the thermoplastic resin composition has various additives other than other resins and inorganic fillers, such as a stabilizer, an ultraviolet absorber, a light stabilizer, a nucleating agent, a colorant, and a lubricant, to the extent that the properties are not impaired. In addition, flame retardants and the like may be appropriately contained. As a method of adding various additives including these inorganic fillers, a known method, for example, the following methods (a) and (b) can be used.

  (A) Various additives were mixed with a polyaryl ketone resin and / or an amorphous polyetherimide resin base material (base resin) at a high concentration (typically about 10 to 60% by mass). A method of preparing a master batch separately, adjusting the concentration of the master batch and mixing the resin, and mechanically blending it using a kneader or an extruder. (B) A method in which various additives are mechanically blended directly with a resin to be used using a kneader or an extruder. Among these methods, the method (a) is preferable from the viewpoint of dispersibility and workability. Further, the surface of the insulating base material 10 made of the thermoplastic resin composition may be appropriately subjected to corona treatment or the like for the purpose of improving the lamination property.

<Conductor pattern 20>
The conductor pattern 20 is a method in which a metal foil is attached to an insulating substrate 10 made of a thermoplastic resin composition by thermocompression bonding and then etched to form the conductor pattern 20, or an insulation made of a thermoplastic resin composition. A method of directly laminating a metal foil when the substrate 10 is formed by extrusion, or a method of forming a conductor pattern 20 by plating by forming a resist on an insulating substrate 10 made of a thermoplastic resin composition, It can form by the method of producing normal circuit patterns, such as. In addition, as will be described below, the thermoplastic resin composition which is a preferred form in the present invention is formed into an amorphous film by quenching film formation, and thus can be thermocompression bonded at a relatively low temperature. As a metal for forming the conductor pattern 20, a metal having a small electric resistance such as Au, Ag, or Cu can be used. Among these, it is preferable to use Cu because of its abundant track record of being used as a conductor pattern of a wiring board and low cost.

<Conductive paste composition>
A via hole 30 is formed in the insulating base material 10 made of the thermoplastic resin composition, and the conductive paste composition is filled therein. The conductive paste composition used in the multilayer wiring board 200 of the present invention contains conductive powder and a binder component.

(Conductive powder)
The conductive powder used in the present invention is composed of first alloy particles and second metal particles.

  The first alloy particles are non-lead solder particles having a melting point of 130 ° C. or higher and 240 ° C. or lower. Examples of such lead-free solder particles include Sn, Sn—Ag, Sn—Cu, Sn—Sb, Sn—Bi, Sn—In, Sn—Zn, Sn—Ag—Cu, Sn—Ag—In, Sn-Ag-In-Bi, Sn-Zn-Bi, Sn-Ag-Bi, Sn-Ag-Cu-Bi, and Sn-Ag-Cu-Sb can be mentioned. Furthermore, the composition and melting point of these lead-free solder particles are described below.

  Sn (232 ° C), SnAg3.5 (221 ° C), SnCu0.7 (227 ° C), SnSb5 (232-240 ° C), SnBi58 (138 ° C), SnIn52 (118 ° C), SnZn9 (199 ° C), SnAg4Cu0. 5 (217-224 ° C), SnAg3.9Cu0.6 (217-223 ° C), SnAg3Cu0.5 (217-220 ° C), SnAg3.5Cu0.9 (217 ° C), SnAg3.8Cu0.7 (217-218 ° C) ), SnAg2.8In20 (175-187 ° C), SnZn8Bi3 (191-198 ° C), SnAg3.4Bi4.8 (201-215 ° C), SnAg2Bi7.5 (191-216 ° C), SnAg1Bi57 (137-139 ° C), SnAg2.5Cu0.5Bi1 (214-221 ° C.), SnAg Cu0.75Bi3 (207-218 ° C), SnAg2.5Cu0.8Sb0.5 (217-225 ° C), SnAg0.2Cu2Sb0.8 (219-235 ° C), SnAg3.5In4Bi0.5 (210-215 ° C), SnAg3. 5In8Bi0.5 (197-208 ° C.). In addition, the number after each said element represents the composition (mass%) of this element. The composition of Sn is other than the other components. For example, in “SnAg3.5”, Sn is 96.5% by mass and Ag is 3.5% by mass.

  These lead-free solder particles are reliable in the effect of metal diffusion of tin. As the first alloy particles, a mixture of two or more of these non-lead solder particles can also be used.

  The second metal particles are at least one or more metal particles selected from the group consisting of Au, Ag, and Cu. The second metal particle is a particle formed of a metal having a low electric resistance value, and bears the electric conductivity of the via. The second metal particles have a higher melting point than the first alloy particles, and have a role of maintaining the viscosity of the conductive paste composition during heating.

  The mixing ratio of the first alloy particles and the second metal particles in the conductive powder is “76/24” or more and less than “90/10” by mass ratio (“first alloy particles” / “second” Metal particles "). When the amount of the first alloy particles is too large beyond this range, the viscosity of the conductive paste composition is greatly reduced when the substrate is heated and laminated, and the conductive paste composition flows out from the via hole 30. There is a risk that.

  The average particle diameter of the first alloy particles and the second metal particles is preferably 10 μm or less. By setting the first alloy particles to such a particle size, the conductive paste composition can be easily filled into the via hole 30, and metal diffusion can easily occur. Moreover, the effect which adjusts the viscosity of the electrically conductive paste composition at the time of carrying out heating lamination | stacking of a board | substrate by using a 2nd metal particle as such a particle size becomes favorable.

  The average particle size difference between the first alloy particles and the second metal particles is preferably 2 μm or less. By aligning the particle diameters as much as possible, metal diffusion bonding can be easily generated.

(Binder component)
The binder component used in the present invention is a thermoplastic resin composition having a Tg lower than the melting point of the first alloy particles and a flow start temperature of 260 ° C. or higher. The binder component has a Tg lower than the melting point of the alloy particles, and the binder component is soft when the first alloy particles are dissolved during lamination pressing. For this reason, the first alloy particles can efficiently diffuse into the metal without being obstructed by the binder component.

  Further, the flow starting temperature of the binder component is 260 ° C. or higher, and the binder component is softened but not fluidized during lamination pressing (press temperature: 150 ° C. or higher and lower than 260 ° C.). For this reason, the fluidized binder component can be prevented from flowing out between the substrates together with the dissolved first alloy particles.

  As described above, in the present invention, the binder component is controlled to be softened but not melted during hot pressing during the production of the multilayer wiring board. In addition, metal diffusion bonding is promoted and connection failures such as wiring short-circuits are prevented. Moreover, although a binder component is soluble in an organic solvent, this is because it dissolves in an organic solvent to form a conductive paste composition. Moreover, it is preferable that the flow start temperature of a binder component is 260 degreeC or more and 270 degrees C or less.

  Examples of the binder component include an amorphous polyester resin, polysulfone resin, polyethersulfone resin, and polyetherimide resin having a flow start temperature of 260 ° C. or higher. Among these, it is preferable to use a binder component having a flow start temperature of 260 ° C. or higher and 270 ° C. or lower, and examples thereof include a polysulfone resin and a polyether sulfone resin.

<The manufacturing method of the wiring board 100a provided with the insulating base material 10 which consists of a thermoplastic resin composition>
1A to 1E show a process for manufacturing a single-layer wiring board 100a. First, as shown to Fig.1 (a), the insulating base material 10 which consists of a thermoplastic resin composition is prepared. The insulating substrate 10 is preferably in the form of a film, a thin plate or a sheet. As a forming method, a known method such as an extrusion casting method using a T die or a calendar method can be adopted, and the method is particularly limited. However, an extrusion casting method using a T-die is preferable from the viewpoints of sheet formability and stable productivity. The molding temperature in the extrusion casting method using a T-die is appropriately adjusted depending on the flow characteristics and film-forming properties of the resin used, but is generally polyaryl ketone resin and amorphous having a crystal melting peak temperature of 260 ° C. or higher. In the case of a mixed composition of a conductive polyetherimide resin, the temperature is 360 to 400 ° C. In addition, it is necessary to form an amorphous film by rapidly forming a film during extrusion casting. Thereby, since the area | region where an elasticity modulus falls in 170-230 degreeC vicinity is expressed, thermoforming and heat fusion in this temperature range are attained. Specifically, the elastic modulus starts to decrease at around 170 ° C., and thermoforming and heat fusion are possible at around 200 ° C. The graph shown in FIG. 3 is obtained by measuring the elastic modulus at a temperature rising rate of 3 ° C./min. When the temperature rising rate is 10 ° C./min, the transition from amorphous to crystalline is delayed. In the vicinity of 230 ° C., the elastic modulus is the lowest.

  Subsequently, as shown in FIG.1 (b), metal foil is affixed on the surface of the insulating base material 10 which consists of a thermoplastic resin composition. As described above, since the insulating base material 10 made of the thermoplastic resin composition is in an amorphous state, the crystallization of the thermoplastic resin does not proceed greatly, and it takes a relatively short time at a temperature slightly above the glass transition temperature. Thus, the metal foil can be attached without causing crystallization of the insulating base material. Further, when forming the insulating base material 10, a metal foil may be laminated at the same time to obtain the stage shown in FIG. An example of the metal foil is a copper foil.

  Next, as shown in FIG. 1C, a via hole 30 is formed at a predetermined position of the insulating base 10 using a laser or a mechanical drill. Next, a conductor pattern 20 is formed as shown in FIG. 1D by a normal method such as applying a resist to the surface of the metal foil in a circuit pattern, etching, and removing the resist. In addition, after forming the via hole 30, the copper foil may be attached to form the conductor pattern 20, or the conductor pattern 20 may be formed and then the via hole 30 may be formed. Is not particularly limited. Subsequently, the via 40 is formed by filling the via hole 30 with a conductive paste composition by a normal printing method such as screen printing, and a single-layer wiring board 100a as shown in FIG. .

<Behavior of elastic modulus with respect to temperature of insulating substrate 10 made of thermoplastic resin composition>
Here, the behavior of the elastic modulus with respect to the temperature of the insulating substrate 10 made of the thermoplastic resin composition will be described. As a thermoplastic resin composition, a mixed composition of a polyaryl ketone resin and an amorphous polyetherimide resin having a crystal melting peak temperature (Tm) of 260 ° C. or higher, particularly a polyether as a polyaryl ketone resin The behavior of the elastic modulus with respect to temperature of the insulating base material 10 when ether ketone is used is shown in FIG.

  “Before lamination” is a graph showing the behavior of the elastic modulus with respect to the temperature of the insulating base material 10 before lamination as the multilayer wiring board 200. Also, “after lamination” is displayed as a graph showing the behavior of the elastic modulus with respect to the temperature of the insulating base material 10 after the multilayer wiring board 200 is formed by heating and pressurizing under predetermined conditions. . In the state before lamination, as described above, the insulating base material 10 is formed into an amorphous film by rapid cooling. Therefore, the elastic modulus is sufficiently lowered in a relatively low temperature region of around 200 ° C. Thereby, the insulating base material 10 before lamination can be thermoformed and heat-sealed at a relatively low temperature.

  The insulating base material 10 formed into an amorphous film changes to crystallinity by heating and pressure molding under predetermined conditions when the multilayer wiring base material 200 is manufactured. Along with this, the elastic modulus of the insulating base material 10 is greatly changed to behave as shown in the graph after lamination in FIG. As a result, the effect of promoting metal diffusion bonding is demonstrated as will be described below, and the resistance value of the via hole of the multilayer wiring board 200 can be made extremely small, as well as moisture absorption heat resistance and connection reliability. In addition, it is considered that the adhesive strength of the conductor can be excellent.

  Next, how metal diffusion bonding is promoted will be described. Here, the relationship between the non-lead solder particles in the conductive paste composition and the insulating base material 10 made of the thermoplastic resin composition is important, and the heat constituting the insulating base material 10 at the melting point of the non-lead solder particles. The storage elastic modulus of the plastic resin composition is preferably 10 MPa or more and less than 7 GPa. As shown in FIG. 3, when the thermoplastic ether composition constituting the insulating substrate 10 is a mixed composition of polyether ether ketone and amorphous polyether imide, which is the preferred form described above. The storage elastic modulus of the thermoplastic resin composition at the melting point of the lead-free solder particles of 130 ° C. or more and 240 ° C. or less is 10 MPa or more and less than 7 GPa. The storage elastic modulus of the thermoplastic resin composition is a value measured using a viscoelasticity evaluation apparatus at a measurement frequency of 1 Hz and a temperature increase rate of 3 ° C./min.

  As described above, in the melting point of the lead-free solder particles, the thermoplastic resin composition constituting the insulating base material 10 has a storage elastic modulus of 10 MPa or more and less than 7 GPa. This means that the plastic resin composition has a certain degree of flexibility and retains a certain degree of elasticity without melting.

  As described above, the conductive paste composition and the thermoplastic resin composition can mutually interact by giving the thermoplastic resin composition constituting the insulating base material 10 a certain degree of flexibility at the melting point of the lead-free solder particles. The adhesion between the conductive paste composition and the insulating substrate 10 made of the thermoplastic resin composition is improved. In addition, the thermoplastic resin composition does not melt at the melting point of the lead-free solder particles, and retains a certain degree of elastic modulus. It can be tightened by the thermoplastic resin composition that is the side surface of the via hole 30, and pressure can be applied to the conductive paste composition. Thereby, it is considered that the tin component in the lead-free solder particles can diffuse into the metal forming the second metal particles and / or the conductor pattern 20 to form a metal diffusion bonding.

<Wiring board 300 made of a material other than the thermoplastic resin composition>
The wiring substrate 300 made of a material other than the thermoplastic resin composition includes a glass epoxy substrate (FR4 substrate), a two-layer polyimide substrate, a pseudo two-layer polyimide substrate, a three-layer polyimide substrate, an LCP (liquid crystal polymer) substrate, and an LTCC (low temperature fired ceramic). ) A substrate can be used. Two or more kinds of these wiring boards 300 may be laminated together to form the multilayer board 200b.

  A method for manufacturing a glass epoxy substrate (FR4 substrate) will be described. First, an insulating base material (prepreg) in which a glass cloth is impregnated with a thermosetting resin to form a semi-cured state (B stage) is prepared. Next, a through-hole penetrating the insulating base material is formed at a predetermined position of the insulating base material using a laser or a mechanical drill, and this is used as a via hole. Next, a conductive paste is filled into the via hole by screen printing or the like. Then, if necessary, the conductive paste is solidified by heating to volatilize the solvent. The conductive paste used for the wiring substrate 300 is not particularly limited, and a general conductive paste used for filling via holes can be used. Moreover, the conductive paste composition used in the wiring base material 100 can also be used as the conductive paste used for the wiring substrate 300. Next, if necessary, the dried and solidified product of the conductive paste protruding on the surface of the insulating base material is removed by mechanical polishing or the like, and copper foil is applied to one or both surfaces of the insulating base material. The insulating substrate is completely cured simultaneously with thermocompression bonding (C-stage). Next, the copper foil is patterned by etching to form a conductor pattern. From the above, it is possible to manufacture the wiring substrate 300 made of a material other than the thermoplastic resin composition using the glass epoxy substrate.

  The “B stage” of the above-described epoxy resin refers to a semi-cured state in which the reaction proceeds to some extent when a resin and a curing agent are mixed. At this stage, most of it is no longer dissolved in the solvent, but when heated, it dissolves and the reaction proceeds further. The “C stage” refers to a completely cured state that is insoluble and infusible at the final stage of the reaction.

  A method for manufacturing a liquid crystal polymer (LCP) substrate will be described. First, an insulating substrate made of LCP is prepared. As the LCP, LCPI type (liquid crystal transition temperature: 350 ° C.), LCP II type (liquid crystal transition temperature: 300 ° C.), or the like can be used. As the insulating substrate made of LCP, a film shape, a thin plate shape, or a sheet shape is preferable. The molding method is preferably a known method, for example, an extrusion casting method using a T die, a calendar method, an inflation molding method, or the like, and is not particularly limited. Considering, an extrusion casting method using a T die is preferable. The molding temperature in the extrusion casting method using a T-die is appropriately adjusted depending on the fluidity and film-forming property of the resin used, but is generally 400 to 420 ° C. for the LCPI type resin and 350 for the LCP II type resin. ~ 370 ° C. The copper foil is affixed at the time of film formation, and then a via hole is formed in the insulating base material and patterned to form a conductor pattern, which is the same as in the above-described method for manufacturing a glass epoxy substrate.

  A two-layer polyimide substrate in which a polyimide layer is formed on a copper foil by a casting method or a casting method, a pseudo two-layer polyimide substrate in which a thermoplastic polyimide layer is bonded as an adhesive layer between a polyimide film and a copper foil, and a polyimide film A three-layer polyimide substrate using a thermosetting adhesive between copper foils can also be manufactured by the same manufacturing method as the above-described glass epoxy substrate and LCP substrate.

  The LTCC (low temperature fired ceramic) substrate is manufactured by forming via holes in the LTCC (low temperature fired ceramic) substrate before firing, filling the via holes with Ag paste, and applying Ag paste wiring to the surface layer and firing. Can do.

<Method for Manufacturing Multilayer Wiring Boards 200a and 200b of the Present Invention>
1E to 1G show the manufacturing process of the multilayer wiring board 200a. As shown in FIG. 1F, a plurality of produced single-layer wiring boards 100a are overlapped. In the illustrated form, three single-layer wiring boards 100a are overlaid. In addition, the lowermost substrate is superposed in a different direction so that the conductor pattern 20 is formed outside the multilayer substrate. Specifically, as shown in FIG. 4, the cushioning film 51, which has three cushion films 51 and wiring substrates 100 a having elasticity and releasability from the lower side, are stacked on the laminated jig 50 with a built-in heater. After that, the pressing jig 52 is pushed down in the direction of the arrow shown in the drawing, so that the three wiring base materials 100a are thermocompression bonded, and these are laminated and integrated to form the multilayer wiring board 200a. As the lamination conditions of each layer, from the viewpoint of effectively causing metal diffusion bonding, it is preferable that the temperature is 150 ° C. or more and less than 260 ° C., the pressure is 3 MPa or more and less than 8 MPa, and the press time is 10 minutes or more and less than 40 minutes. Note that the lamination temperature is preferably equal to or higher than the melting point of the first alloy particles. In the present invention, the binder component is defined so that the lamination temperature is between the Tg of the binder component and the flow start temperature. By using such a binder component, metal diffusion bonding can be effectively caused and electrical connection reliability can be improved.

  1 (h) to (l) show a multilayer structure in which a wiring board 100b provided with an insulating base material 10 made of a thermoplastic resin composition and a wiring board 300 made of a material other than the thermoplastic resin composition are alternately stacked. It is the figure which showed the process of manufacturing the wiring board 200b. First, as shown in FIG.1 (h), the insulating base material 10 which consists of a thermoplastic resin composition is prepared. The molding method is the same as in the case of FIG. Next, as shown in FIG. 1 (i), a via hole 30 is formed at a predetermined position of the insulating substrate 10 using a laser or a mechanical drill. Then, by a normal printing method such as screen printing, the formed via hole 30 is filled with the conductive paste composition, and the single-layer wiring board 100b in which the via 40 as shown in FIG. 1 (j) is formed is manufactured. Is done.

  Next, as shown in FIG. 1 (k), the manufactured single-layer wiring board 100b and the wiring board 300 made of a material other than the thermoplastic resin composition different from the wiring board 100b are alternately stacked. In the illustrated embodiment, the wiring board 300 made of a material other than the thermoplastic resin is disposed on both sides of the wiring board 100b in the middle.

  Then, under predetermined conditions, the layers are heat-sealed to produce a multilayer wiring board 200b as shown in FIG. The lamination method and lamination conditions are the same as the method and conditions shown in FIG.

  In addition, in the manufacturing method shown to Fig.1 (a)-(g), the conductor pattern 20 is formed in the single side | surface of the single layer wiring board 100a, and also shown to FIG.1 (h)-(l). In the manufacturing method, the conductor pattern 20 is formed on both surfaces of the wiring board 300 made of a material other than the thermoplastic resin composition without forming the conductor pattern 20 on the single-layer wiring board 100b, but the multilayer wiring board 200a to be manufactured is formed. As long as the conductor pattern 20 is formed at a desired position in 200b, the position where the conductor pattern is formed in the single-layer wiring boards 100a, 100b, 300 is not particularly limited, and can be changed as appropriate.

Example 1
As a binder component of the conductive paste composition, a polyether having a glass transition temperature (Tg) measured by a differential scanning calorimeter at a heating rate of 10 ° C./min is 223 ° C. and a flow start temperature is 264.6 ° C. A sulfone resin was used.

  As the first alloy particles of the conductive powder, SnSb5 (average particle size 5.1 μm) having a melting point of 232 ° C. to 240 ° C. and Cu (average particle size 5.0 μm) as the second metal particles are in a mass ratio of 76/24. (First alloy particle / second metal particle). Then, 7 parts by mass of methylene chloride solution was added as a solvent to 93 parts by mass of the conductive powder and binder component blended at a mass ratio of 97/3 (conductive powder / binder component), and the mixture was roughly mixed with a planetary mixer. After kneading, kneading with three rolls, defoaming with a planetary mixer, and a viscosity at 25 ° C. measured by Brookfield viscometer DV-III spindle CP52 (angle 3.0 °, φ2.4 cm) is 183 Pa · A conductive paste composition of s (1 rpm) was obtained.

  Next, as an insulating base material made of a thermoplastic resin, a polyether ether ketone resin (product name PEEK450G) and a polyetherimide resin (product name PEI Ultem 1000) are used in a mass ratio of 40/60 (polyether ether ketone / polyether imide). To 100 parts by mass of the blended resin mixture, 39 parts by mass of mica having an average particle size of 3.5 μm and an average aspect ratio of 50 as an inorganic filler was added and melt-kneaded, and this kneaded product was further extruded by a T-die extrusion casting method. The film was rapidly cooled to obtain a film having a thickness of 50 μm.

  The elastic modulus of this film at a melting point of 232 ° C. to 240 ° C. of SnSb5 was 37 MPa with a viscoelasticity measuring device under the conditions of 1 Hz and a heating rate of 3 ° C./min. Moreover, the copper foil (thickness 12 micrometers) was laminated at the time of extrusion, and the single-sided copper clad board was produced besides the film.

  Next, a via hole having a hole diameter of 100 μm was formed at a predetermined position of the single-sided copper-clad plate using a laser. Next, as shown in FIG. 1D, a conductor evaluation pattern having a bottomed via is formed by applying a resist to the surface of the copper foil in a circuit pattern, etching, and removing the resist. A circuit processed substrate was prepared. Next, this via hole is filled with the conductive paste composition prepared above using a screen printing method, and after filling, the solvent is volatilized at 125 ° C. for 45 minutes to form a via, as shown in FIG. A simple single-layer wiring board 100a was produced.

  Next, 10 single-layer wiring boards 100a thus produced are stacked with only the lowermost single-layer board changed in its direction, and the melting point of the first alloy particles SnSb5 in the via is 232 ° C. to 240 ° C. or higher. These were laminated together at 240 ° C. and 5 MPa for 30 minutes to obtain a multilayer wiring board. In this multilayer wiring board, the copper circuit pattern exposed on the front side and the copper circuit pattern exposed on the back side are in a one-to-one correspondence with the via wiring in the inner layer portion, and 10,000 for one test board. A route wiring net is provided. The via / via distance is 250 μm at the minimum.

  Next, a method for evaluating the electrical reliability of this substrate is to dehumidify the multilayer wiring board over 125 ° C. for 24 hours, and then leave it in an atmosphere of 85 ° C. and 85% RH for 16 hours to forcibly absorb moisture. The initial resistance value was measured after passing through a reflow furnace having a maximum temperature of 260 ° C. four times, and the resistance value after 500 cycles of a −25 ° C./125° C. thermal shock test was measured. If the increase was less than 0.5Ω for all wiring nets, it was determined as OK. For those with 0.5Ω or more, the abnormal wiring net location of the evaluated multilayer wiring board was specified, and the cause was examined by observing the cross section with SEM. The result of the electrical reliability evaluation test of the multilayer wiring board of Example 1 was less than 0.5Ω in all wiring nets.

(Example 2)
A multilayer structure was obtained in the same manner as in Example 1 except that the conductive paste composition was obtained by setting the mass ratio of the first alloy particles to the second metal particles to 80/20 (first alloy particles / second metal particles). A wiring board was obtained. Then, electrical reliability was evaluated. The results are shown in Table 1.

(Example 3)
A multilayer structure was obtained in the same manner as in Example 1 except that the conductive paste composition was obtained by setting the mass ratio of the first alloy particles to the second metal particles to 88/12 (first alloy particles / second metal particles). A wiring board was obtained. Then, electrical reliability was evaluated. The results are shown in Table 1.

(Comparative Example 1)
A multilayer structure was obtained in the same manner as in Example 1 except that the conductive paste composition was obtained by setting the mass ratio of the first alloy particles to the second metal particles to 72/28 (first alloy particles / second metal particles). A wiring board was obtained. Then, electrical reliability was evaluated. The results are shown in Table 1.

(Comparative Example 2)
A multilayer structure was obtained in the same manner as in Example 1 except that the conductive paste composition was obtained by setting the mass ratio of the first alloy particles to the second metal particles to 92/8 (first alloy particles / second metal particles). A wiring board was obtained. Then, electrical reliability was evaluated. The results are shown in Table 1.

Example 4
A multilayer wiring board was obtained in the same manner as in Example 1 except that the conductive paste and the binder component were blended at a mass ratio of 92/8 (conductive powder / binder component) to obtain a conductive paste composition. Then, electrical reliability was evaluated. The results are shown in Table 1.

(Comparative Example 3)
A multilayer wiring board was obtained in the same manner as in Example 1 except that the conductive paste and the binder component were blended at a mass ratio of 88/12 (conductive powder / binder component) to obtain a conductive paste composition. Then, electrical reliability was evaluated. The results are shown in Table 1.

(Comparative Example 4)
A multilayer wiring board was obtained in the same manner as in Example 1 except that a conductive paste composition was obtained by blending the conductive powder and the binder component in a mass ratio of 98/2 (conductive powder / binder component). Then, electrical reliability was evaluated. The results are shown in Table 1.

(Example 5)
As a binder component, a polysulfone resin having a glass transition temperature (Tg) measured with a differential scanning calorimeter at a temperature rising rate of 10 ° C./min is 190 ° C. and a flow start temperature is 260.5 ° C. is used. A multilayer wiring board in the same manner as in Example 1 except that the conductive paste composition was obtained using SnAg3.5Cu0.5 (average particle size 5.6 μm) having a melting point of 217 ° C. to 218 ° C. as the alloy particles. Got. Then, electrical reliability was evaluated. The results are shown in Table 1.

(Example 6)
As a binder component, a polyetherimide resin (Ultem1000 (GE) having a glass transition temperature (Tg) measured by a differential scanning calorimeter at a heating rate of 10 ° C./min at 216 ° C. and a flow start temperature of 274.4 ° C. A multilayer wiring board was obtained in the same manner as in Example 1 except that a conductive paste composition was obtained using Then, electrical reliability was evaluated. The results are shown in Table 1.

(Comparative Example 5)
As a binder component, an amorphous polyester resin (byonbo, manufactured by Toyobo Co., Ltd.) having a glass transition temperature (Tg) measured by a differential scanning calorimeter at a heating rate of 10 ° C./min at 60 ° C. and a flow start temperature of 120 ° C. A multilayer wiring board was obtained in the same manner as in Example 1 except that GK250) was used and a conductive paste composition was obtained using a butyl carbitol acetate solution as a solvent. Then, electrical reliability was evaluated. The results are shown in Table 1.

  From Table 1, in the multilayer wiring board (Examples 1 to 6) of the present invention, the resistance value increase amount was less than 0.5Ω in all the wiring nets, and good results were shown.

  While the present invention has been described in connection with embodiments that are presently the most practical and preferred, the present invention is not limited to the embodiments disclosed herein. However, the invention can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and a multilayer wiring board accompanying such a change is also included in the technical scope of the present invention. Must be understood as.

It is the figure which showed the outline | summary of the manufacturing method of the multilayer wiring board 200 of this invention. It is the figure which showed a mode that the elasticity modulus of the specific thermoplastic resin composition which comprises the insulating base material 10 changes with temperature. It is a conceptual diagram of the lamination jig | tool 50 for manufacturing the multilayer wiring board 200 by thermocompression bonding the wiring board 100. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Insulation base material which consists of thermoplastic resins 20 Conductor pattern 30 Via hole 40 Via 100a, 100b Single layer wiring board 200a, 200b Multilayer wiring board 50 Lamination jig 51 Cushion film 52 Pressing jig

Claims (8)

An insulating substrate made of a thermoplastic resin composition, a wiring board comprising a conductor pattern provided on the insulating substrate, and a via formed by filling the insulating substrate with a conductive paste composition, A multilayer wiring board in which a plurality of wiring boards are superposed on each other or alternately superposed on a wiring board made of a material other than a thermoplastic resin composition, which is different from the wiring board, and laminated or sequentially laminated by thermal fusion. Because
The conductive paste composition includes a conductive powder and a binder component, and a mass ratio of the conductive powder and the binder component is 90/10 or more and less than 98/2,
The conductive powder comprises first alloy particles and second metal particles,
The first alloy particles are non-lead solder particles having a melting point of 130 ° C. or higher and 240 ° C. or lower, and the second metal particles are at least one selected from the group consisting of Au, Ag, Cu, The mass ratio between the first alloy particles and the second metal particles is 76/24 or more and less than 90/10,
The multilayer wiring board, wherein the binder component is a thermoplastic resin composition having a Tg of less than the melting point of the first alloy particles and a flow start temperature of 260 ° C or higher.   The multilayer wiring board according to claim 1, wherein the binder component is at least one selected from a polysulfone resin and a polyethersulfone resin.   3. The multilayer wiring board according to claim 1, wherein an average particle size of the first alloy particles and the second metal particles is 10 μm or less, and an average particle size difference is 2 μm or less.   The first alloy particles are Sn, Sn—Ag, Sn—Cu, Sn—Sb, Sn—Bi, Sn—In, Sn—Zn, Sn—Ag—Cu, Sn—Ag—In, Sn—Ag—. One or more lead-free solder particles selected from the group consisting of In—Bi, Sn—Zn—Bi, Sn—Ag—Bi, Sn—Ag—Cu—Bi, and Sn—Ag—Cu—Sb, The multilayer wiring board according to any one of claims 1 to 3.   The multilayer wiring board according to any one of claims 1 to 4, wherein a storage elastic modulus of the thermoplastic resin composition constituting the insulating base material at a melting point of the lead-free solder particles is 10 MPa or more and less than 7 GPa. .   The thermoplastic resin composition constituting the insulating substrate is a mixed composition of a polyaryl ketone resin and an amorphous polyetherimide resin having a crystal melting peak temperature (Tm) of 260 ° C or higher. The multilayer wiring board according to claim 5.   A wiring substrate made of a material other than the thermoplastic resin is a glass epoxy substrate (FR4 substrate), a two-layer polyimide substrate, a pseudo two-layer polyimide substrate, a three-layer polyimide substrate, a liquid crystal polymer (LCP) substrate, and a low-temperature fired ceramic ( The multilayer wiring board according to claim 1, wherein the multilayer wiring board is at least one wiring board selected from the group consisting of (TLCC) boards.   The batch lamination or sequential lamination by thermal fusion of the wiring board is performed at a temperature of 150 ° C. or more and less than 260 ° C. and a pressure of 3 MPa or more and less than 8 MPa, and between the first alloy particles and the second metal particles. 8. The multilayer wiring board according to claim 1, wherein metal diffusion bonding is formed between the first alloy particles and the metal forming the conductor pattern.

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