JP2009054773A - Multilayer wiring board and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the conductive reliability under the thermal cycling environment in a multilayer wiring board employing a structure wherein the interlayer conduction is obtained with conductive paste filled into a via hole. <P>SOLUTION: This invention is a multilayer wiring board, wherein conductor layers 12a, 12b are arranged at both sides of an insulating substrate 11 and are electrically connected with each other through a conductive paste layer 15 that is filled into a via hole 14 on a laminated plate 20. First and second conductive pastes 16, 17 are filled in laminae along the radial direction of the via hole 14 to form many connection interfaces extending in the depth direction of the via hole 14. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a multilayer wiring board (multilayer printed wiring board) used for electronic devices and the like, and more particularly, to a multilayer wiring board having a structure in which interlayer conduction is obtained by a conductive paste filled in via holes and a method for manufacturing the same.

  In recent years, electronic devices have become smaller and lighter in addition to higher-frequency and digitized signals, and accordingly, printed wiring boards mounted on electronic devices are also required to have higher densities and multilayers. It has become a thing. In multilayer wiring boards with multiple printed wiring boards, via holes such as IVH (Interstitial Via Hole) are formed in the insulating base material, and conductive via paste is filled in the via holes, thereby providing conduction (interlayer conduction) between the front and back of the board. What you get is common.

For example, a multilayer printed board is known in which interlayer conduction is obtained by filling a through hole of a printed board with a conductive paste in which a metal filler is dispersed in a resin (see Patent Document 1). Also, a via forming method is known in which a conductive material in a powder form is filled in a through hole of a printed circuit board, and a conductive paste is applied thereon and baked to obtain interlayer conduction (Patent Document 2). reference). In addition, a multilayer wiring board is known in which interlayer conduction is obtained by laminating and filling a microparticle conductive paste and a nanoparticle conductive paste in a through hole of a printed board (see Patent Document 3).
Japanese Patent Laid-Open No. 7-176846 Japanese Patent Publication No. 7-79195 Japanese Patent Laying-Open No. 2005-340279

  FIG. 9 is a partial cross-sectional view of an IVH portion in a conventional general multilayer wiring board. As shown in FIG. 9, the printed wiring board 100 includes a laminated board (insulating layer) 110 having an insulating base material 101 and an adhesive layer 103 bonded to each other, and via holes 104 are formed at predetermined positions. Has been. A conductive layer 102 a serving as a circuit pattern is formed at the position of the via hole 104 on the surface of the laminate 110 on the insulating base 101 side. The via hole 104 is filled with a conductive paste 105.

  When the printed wiring boards configured as described above are stacked and thermocompression bonded, the conductive paste 105 of each printed wiring board is compressed with high density. As a result, the conductive paste 105 and the conductor layers 102a and 102b are in close contact with each other, and electrical conduction between the front and back of the substrate is obtained. In FIG. 9, a conductor layer 102b disposed below the conductive paste 105 indicates a conductor layer formed on another printed wiring board (not shown) that is laminated.

  The conductive paste 105 used for electrical conduction of the multilayer wiring board as described above is obtained by dispersing a metal filler in a resin binder. When the conductive paste 105 is filled in the via hole 104 and then sintered, an alloy layer 107 is formed at the interface between the conductor layer 102a (102b) and the conductive paste 105. If the connection strength between the alloy layer 107 and the conductor layer 102a (102b) is weak, the contact between the conductor layer 102a (102b) and the conductive paste 105 becomes insufficient due to repeated stress caused by the thermal cycle in the actual use environment. There is a possibility that a problem occurs in electrical continuity.

That is, the insulating base material 101 and the adhesive layer 103 have a larger coefficient of thermal expansion than that of the conductive paste 105, and the expansion / contraction due to the cooling / heating cycle is also large. Such expansion / contraction acts as stresses F ₁ and F ₂ as indicated by arrows in FIG. For this reason, when the expansion / contraction of the insulating base material 101 and the adhesive layer 103 is repeated by the cooling / heating cycle, the stresses F ₁ and F ₂ are peeled off between the conductor layer 102a (102b) and the conductive paste 105. Thus, cracks are likely to occur between the conductor layer 102a (102b) and the alloy layer 107 (interlayer connection portion). Then, the contact between the conductor layer 102a (102b) and the conductive paste 105 becomes insufficient due to the crack, and a problem occurs in electrical conduction.

  An object of the present invention is to provide a multilayer wiring board having high electrical connection reliability between a conductor layer and a conductive paste and having high electrical connection reliability even in an environment of a thermal cycle and a method for manufacturing the same. It is in.

  In order to achieve the above object, the invention according to claim 1 is directed to an electroconductive composition in which first and second conductor layers are disposed on both sides of an insulating layer and filled in interlayer conduction holes formed in the insulating layer. A multilayer wiring board in which the first and second conductor layers are electrically connected by a layer, wherein a plurality of connection interfaces extending in the depth direction of the interlayer conduction holes are formed, and a plurality of types of conductive compositions are formed. Filled in layers along the radial direction of the interlayer conduction holes, the conductive composition layer includes a layer made of a first conductive composition, a layer made of a second conductive composition, and the first conductive composition layer And a layer made of an alloy layer containing an alloy of the first conductive metal in one conductive composition and the second conductive metal in the second conductive composition.

  The invention according to claim 2 includes an insulating base material and an adhesive layer laminated to each other, an insulating layer in which an interlayer conduction hole is formed, and a plurality of connection interfaces extending in the depth direction of the interlayer conduction hole. The conductive composition layer formed and filled in layers along the radial direction of the interlayer conduction hole, and the conductive composition formed at the position of the interlayer conduction hole on the surface of the insulating layer on the insulating substrate side A first conductor layer electrically connected to the object, and a second conductor layer formed at a position of the interlayer conduction hole on the surface of the insulating layer on the adhesive layer side and electrically connected to the conductive composition The conductive composition layer includes a layer made of a first conductive composition, a layer made of a second conductive composition, and a first conductive metal in the first conductive composition. And a layer made of an alloy layer containing an alloy with the second conductive metal in the second conductive composition. A multilayer wiring board, wherein.

  According to a third aspect of the present invention, a conductive layer is disposed on both sides of an insulating layer having an insulating base material and an adhesive layer, and the conductive layer is electrically connected to an interlayer conduction hole formed in the insulating layer. A method of manufacturing a multilayer wiring board in which a wiring board filled with a conductive composition is laminated, wherein an adhesive layer and a mask are provided on a surface opposite to the conductor layer of an insulating substrate provided with a conductor layer on one side. Forming a layer, forming an interlayer conduction hole having the conductor layer as a bottom in the insulating base, and forming a plurality of connection interfaces extending in a depth direction of the interlayer conduction hole. A step of filling a seed conductive composition in layers along the radial direction of the interlayer conduction hole, and a step of removing the mask layer to expose the adhesive layer and the end of the conductive composition And stacking a plurality of wiring boards including the wiring boards manufactured through the above steps Characterized in that it comprises the step of wearing.

  The invention according to claim 4 comprises the step of forming a through hole having a diameter smaller than the diameter of the interlayer conduction hole in the conductor layer as the bottom of the interlayer conduction hole according to claim 3, In the step of filling, the outside of the through hole is set to a negative pressure, a part of the conductive composition introduced from the upper part of the interlayer conduction hole is pulled out from the through hole, and the remaining conductive composition is removed. It is a method for manufacturing a multilayer wiring board, wherein the multilayer wiring board is formed on a side wall of the interlayer conduction hole.

  According to the present invention, since a different kind of alloy layer is formed along the radial direction of the interlayer insulating hole, the crack in the interlayer connection portion is less likely to grow compared to the conventional structure in which a uniform interface is formed, and the conductor layer And the durability of electrical conduction between the conductive composition and the conductive composition can be enhanced. Therefore, a multilayer wiring board with high conduction reliability can be obtained even in an environment of a thermal cycle.

  Hereinafter, embodiments of a multilayer wiring board and a manufacturing method thereof according to the present invention will be described.

[Embodiment 1]
FIG. 1 is a partial sectional view of a multilayer wiring board according to the first embodiment, and particularly shows the structure of an IVH portion. The printed wiring board 10 shown in the present embodiment includes a laminated board (insulating layer) having an insulating base material 11 and an adhesive layer 13 bonded to each other, and via holes (interlayer conduction holes) 14 formed at predetermined positions. 20. A conductive layer 12 a serving as a circuit pattern is formed at the position of the via hole 14 on the surface of the laminate 20 on the insulating base material 11 side. A conductive paste layer 15 made of a plurality of conductive pastes (conductive composition), which will be described later, is formed inside the via hole 14 having the conductor layer 12a as a bottom. In FIG. 1, a conductor layer 12b disposed below the conductive paste layer 15 indicates a conductor layer formed on another printed wiring board (not shown) that is laminated.

  As the insulating substrate 11, for example, a flexible resin film such as polyimide or LCP (Liquid Crystal Polymer) can be used.

  As the conductor layers 12a and 12b, for example, conductive members such as copper foil can be used.

  As the adhesive layer 13, for example, a thermoplastic resin film such as thermoplastic polyimide, or a thermosetting resin film such as epoxy, polyester, phenol, or acrylic can be used.

  The conductive paste layer 15 includes a first conductive paste 16, a second conductive paste 17, and an alloy layer 18 formed at the connection interface between these two pastes. As the first and second conductive pastes 16 and 17, polymer type conductive paste in which μm-sized metal filler (copper, tin, silver, etc.) is dispersed in a resin binder and mixed with a viscous medium containing a solvent to form a paste. Can be used. In the present embodiment, as will be described later, an example in which a copper paste is used as the first conductive paste 16 and a tin paste is used as the second conductive paste 17 is shown as a plurality of types of conductive paste. However, the present invention is not limited to this, and any combination of conductive pastes of different types may be used.

  Furthermore, as a method of filling the above-described conductive paste into the via hole 14, for example, a screen printing method, a dispensing method, an ink jet method, electroless plating, or the like can be used.

The first conductive paste 16 and the second conductive paste 17 are filled in layers along the radial direction of the via hole 14 so that a plurality of connection interfaces extending in the depth direction of the via hole 14 are formed. . That is, the first conductive paste 16 is first formed on the side wall of the via hole 14, and then the second conductive paste 17 is formed inside the via hole 14 having the first conductive paste 16 as an inner wall. 14 is filled with two types of conductive paste. The first conductive paste 16 and the second conductive paste 17 are formed concentrically when viewed from an arrow A in FIG. When the via hole 14 is filled with the first conductive paste 16 and the second conductive paste 17 and then subjected to a sintering process, the connection between the first conductive paste 16 and the second conductive paste 17 is performed. An alloy layer 18 containing an alloy of the conductive metal in the first conductive paste 16 and the conductive metal in the second conductive paste 17 is formed at the interface. In addition, you may form the alloy layer 18 by sintering simultaneously with the thermocompression bonding of the laminated printed wiring board.
By laminating a predetermined number of printed wiring boards including the printed wiring board 10 configured as described above and thermocompression bonding, the conductor layer 12a, the conductive paste layer 15, and the conductor layer 12b are in close contact with each other. Electrical conduction between the conductor layers 12a and 12b is obtained via the conductive paste layer 15.

  In the present embodiment, the printed wiring board 10 constituting the multilayer wiring board has a plurality of types of conductive paste along the radial direction of the via hole 14 so that a plurality of connection interfaces extending in the depth direction of the via hole 14 are formed. FIG. 1 is a partially enlarged view of FIG. 1 at each connection interface between the conductor layer 12a (12b), the first and second conductive pastes 16 and 17, and the alloy layer 18. As shown in FIG. 2, alloy layers 16a, 17a and 18a having different thicknesses and connection strengths are formed.

  Thus, since a plurality of alloy layers having different thicknesses and connection strengths are formed at the connection interface between the conductor layer 12a (12b) and the conductive paste layer 15, a conventional structure in which a uniform alloy layer is formed. As shown in FIG. 9, cracks generated in the interlayer connection portion do not grow at a stretch, and the growth of cracks is suppressed in any alloy layer.

  That is, according to the structure of the present embodiment, a plurality of different alloy layers are formed along the radial direction of the via hole 14, so that cracks are less likely to grow compared to the conventional structure in which a uniform interface is formed. There is. Therefore, the contact between the conductor layer 12a (12b) and the conductive paste layer 15 is maintained, and the durability of electrical conduction can be enhanced. As a result, a multilayer wiring board with high conduction reliability can be obtained even in an environment of a thermal cycle.

  Next, the manufacturing method of the multilayer wiring board concerning this embodiment is demonstrated, referring FIG.3 and FIG.4. FIGS. 3A to 3I and FIGS. 4J to 4L are schematic views showing the manufacturing process of the multilayer wiring board according to this embodiment. In the embodiments described below, materials, processing methods, and the like are merely examples. That is, the present invention includes various embodiments that are not described herein, and the technical scope of the present invention is determined only by the invention specifying matters related to the appropriate claims from the above description. Is.

  First, as shown in FIG. 3A, a laminate (insulating layer) 20 in which a copper foil conductor layer 12 is bonded to the surface of an insulating base material 11 made of polyimide is used as a starting material, and shown in FIG. 3B. As described above, the circuit pattern is formed by photolithography so that only necessary portions become wiring. Hereinafter, the conductor layers 12 a and 12 b are also referred to as the conductor layer 12.

  Next, as shown in FIG. 3C, a thermoplastic polyimide resin film to be the adhesive layer 13 is laminated on the back surface of the insulating base material 11. Subsequently, as shown in FIG. 3D, a plastic film that becomes the masking film 19 is laminated on the surface of the adhesive layer 13. The masking film 19 serves to prevent the first conductive paste described later from being applied to the adhesive layer 13 except for the inside of the via hole 14.

  The material of the masking film 19 is not particularly limited, and a plastic film such as polyethylene terephthalate, polyethylene naphthalate, polyfinylene sulfite, polyimide, polypropylene, polyethylene, epoxy resin, silicone resin, phenol resin, melamine resin may be used. it can. The lamination of the masking film 19 can be performed using a roll laminator or a parallel plate press. Moreover, you may make it implement these methods in a vacuum.

  Next, as shown in FIG. 3 (e), a carbon dioxide laser is irradiated from a predetermined position on the masking film 19 to form a via hole 14 having the conductor layer 12 as a bottom. In addition to the carbon dioxide laser, for example, a laser such as a UV-YAG laser or an excimer laser can be used to form the via hole 14.

  In addition, after the via hole 14 is formed, in order to improve the connection reliability between the conductor layer 12 and the conductive paste layer 15, a desmear process for removing smear remaining in the via hole 14 is performed as necessary. Also good. Moreover, in order to remove copper oxide, you may wash | clean using aqueous solutions, such as hydrochloric acid and a sulfuric acid.

  Next, as shown in FIG. 3F, a copper paste to be the first conductive paste 16 is formed on the sidewall of the via hole 14 by screen printing. Next, after the copper paste is dried, as shown in FIG. 3G, a tin paste to be the second conductive paste 17 is formed by screen printing in the via hole 14 having the first conductive paste 16 as an inner wall. Form. And as shown in FIG.3 (h), the 1st conductive paste 16 and the 2nd conductive paste 17 are sintered, and the connection interface of the 1st conductive paste 16 and the 2nd conductive paste 17 is carried out. The alloy layer 18 is formed. Thereby, the first conductive paste 16 and the second conductive paste 17 are filled in layers along the radial direction of the via hole 14 so that a plurality of connection interfaces extending in the depth direction of the via hole 14 are formed. It will be. Further, as shown in FIG. 3I, the masking film 19 is removed to expose the adhesive layer 13 and the protrusion 15a of the conductive paste layer 15, respectively.

  Through the above steps (a) to (i), one printed wiring board 10 is completed. This is produced as much as necessary.

Next, as shown in FIG. 4 (j), a plurality of printed wiring boards 10 manufactured in the same process as described above, and a lowermost layer in which a conductor layer 12 serving as a circuit pattern is formed on an insulating base material 11. The printed wiring board 30 is aligned and stacked. The alignment is performed using, for example, a method based on image recognition or a method such as passing a pin through a hole (not shown) provided in each printed wiring board 10. Further, as shown in FIG. 4 (k), the stacked printed wiring boards 10 and 30 are thermocompression bonded by a press machine. At this time, sintering is performed simultaneously, and alloy layers 16a, 17a, and 18a are formed between the conductive paste layer 15 and the conductor layer 12b.
As a result, the adhesive layer 13 of the printed wiring boards 10 and 30 and the corresponding insulating base material 11 are adhered to each other to complete a multilayered wiring board 40. In addition, by thermocompression bonding, the protrusions 15 a of the conductive paste layer 15 are pressed against the conductive layer 12 b (circuit pattern) of the printed wiring board and are crushed to fill the via holes 14 with high density. At the same time, alloy layers 16a, 17a and 18a are formed between the conductive paste layer 15 and the conductor layer 12b, and the conductive paste layer 15 and the conductor layer 12b are in close contact with each other, so that electrical conduction between the front and back of the substrate is obtained. It is done.

  Then, as shown in FIG. 4L, a cover lay or a solder resist to be the insulating film 41 is formed so as to cover the surface of the printed wiring board 10 which is the uppermost layer. 4J to 4L, the cross section of the conductive paste layer 15 is represented by a single pattern.

[Embodiment 2]
Next, as a second embodiment, another method for filling the inside of the via hole 14 with the conductive paste layer 15 will be described. FIGS. 5A to 5E are schematic views showing a filling process of the conductive paste layer 15 in the second embodiment. Each process shown here corresponds to FIGS. 3 (f) and 3 (g), and the other processes are the same as those in the first embodiment, and thus the description thereof is omitted.

  Following the step of FIG. 3 (e) described in the first embodiment, as shown in FIG. 5 (a), a through hole 21 having a diameter smaller than the diameter of the via hole 14 is formed in the conductor layer 12 serving as the bottom of the via hole 14. Form. Next, as shown in FIG. 5B, a squeeze plate 22 is set on the surface of the masking film 19, and the squeeze plate 22 is moved in the direction of the arrow x to form a copper paste that becomes the first conductive paste 16. Squeeze At this time, the outside of the through hole 21 is set to a negative pressure by evacuating the through hole 21 with a predetermined degree of vacuum. As a result, as shown in FIG. 5C, a part of the first conductive paste 16 put into the via hole 14 by squeezing is extracted outside from the direction of the arrow y, and the remaining first conductive paste is removed. A paste 16 is formed on the side wall of the via hole 14. Next, as shown in FIG. 5 (d), the tin paste is squeezed by the same method while evacuating at a degree of vacuum so that the tin paste that becomes the second conductive paste 17 does not come off, and the second conductive paste The conductive paste 17 is formed on the side wall of the first conductive paste 16. As a result, the first conductive paste 16 and the second conductive paste 17 are filled into the via hole 14.

  Then, as shown in FIG. 5 (e), the first conductive paste 16 and the second conductive paste 17 are subjected to a sintering process, whereby a connection interface between the first conductive paste 16 and the second conductive paste 17 is obtained. The alloy layer 18 is formed. Thereby, the first conductive paste 16 and the second conductive paste 17 are filled in layers along the radial direction of the via hole 14 so that a plurality of connection interfaces extending in the depth direction of the via hole 14 are formed. It will be. The subsequent steps are the same as those shown in FIGS.

  In the present embodiment, since a part of the conductive paste layer 15 is exposed from the through hole 21 formed in the conductor layer 12, it is directly connected to the conductive paste layer 15 of the opposite printed wiring board at the time of lamination. .

  Further, in this embodiment, the negative pressure is applied to the outside of the through hole 21 formed in the conductor layer 12 during squeezing, so that each conductive paste can be efficiently filled in the via hole 14. . In addition, bubbles contained in the conductive paste are discharged from the through holes 21, and no bubbles remain in the via hole 14, so that the conductive paste can be filled more densely. Therefore, the adhesiveness between the conductor layer 12 and the conductive paste layer 15 can be improved, and the mechanical reliability and electrical reliability between the conductor layer 12 and the conductive paste layer 15 can be improved. Become.

[Embodiment 3]
In the first and second embodiments, the example in which the first conductive paste 16 and the second conductive paste 17 are formed in two layers along the radial direction of the via hole 14 has been described. In the third embodiment, a plurality of layers are further formed. An example in which is formed will be described.

  6A and 6B are schematic views showing a filling process of the conductive paste layer 15 in the third embodiment. Each process shown here corresponds to FIGS. 3 (f) and 3 (g), and the other processes are the same as those in the first embodiment, and thus the description thereof is omitted. Further, the method of forming the through hole 21 and the method of squeezing the conductive paste are the same as those shown in FIGS.

  Also in this embodiment, squeezing and vacuuming of the first conductive paste 16 and the second conductive paste 17 are alternately performed by the method described in the second embodiment. Here, as shown in FIG. 6A, the degree of vacuum is set so that the first conductive paste 16 and the second conductive paste 17 are formed thinner than in the second embodiment. Then, after forming the second conductive paste 17 after the first conductive paste 16, the first conductive paste 16 is formed again. The first conductive paste 16 that is finally filled is squeezed while being evacuated at a degree of vacuum so that the copper paste does not fall off, and is filled into the via hole 14.

  Then, as shown in FIG. 6B, the first conductive paste 16 and the second conductive paste 17 are sintered to sinter the first conductive paste 16 and the second conductive paste 17. A plurality of alloy layers 18 are formed. Thereby, the first conductive paste 16 and the second conductive paste 17 are filled in layers along the radial direction of the via hole 14 so that a plurality of connection interfaces extending in the depth direction of the via hole 14 are formed. It will be. The subsequent steps are the same as those shown in FIGS.

  Also in this embodiment, since a part of the conductive paste layer 15 is exposed from the through hole 21 formed in the conductor layer 12, it is directly connected to the conductive paste layer 15 of the opposite printed wiring board at the time of lamination. Become.

  According to the configuration of the present embodiment, more alloy layers having different thicknesses and connection strengths are formed at the connection interface between the conductor layer 12 and the conductive paste layer 15 than in the first embodiment. The effect of suppressing the growth of can be further enhanced.

  By repeating the step of forming the first conductive paste 16 and the second conductive paste 17 as described above alternately any number of times, the thickness or the thickness of the connection interface between the conductor layer 12 and the conductive paste layer 15 can be reduced. More alloy layers having different connection strengths can be formed.

  Examples of the multilayer wiring board according to the present invention and comparative examples will be described below. In addition, this invention is not limited to what was shown in the following Example, In the range which does not change the summary, it can change suitably and can implement.

[Test 1]
Here, the multilayer wiring board having the structure of the second embodiment described above is referred to as Example 1. That is, in Example 1, as shown in FIG. 5E of the second embodiment, a multilayer wiring board having a structure in which a first conductive paste 16 is formed in one layer and the second conductive paste 17 is filled therein is formed. did. Moreover, the multilayer wiring board was produced with the structure of the patent documents 1-3 demonstrated previously as a comparative example. That is, Patent Document 1 (JP-A-7-176646) is compared with Comparative Example 1, Patent Document 2 (JP-B-7-79195) is compared with Comparative Example 2, and Patent Document 3 (JP-A 2005-340279) is compared. Example 3 was used.

  As a common configuration, a 12 μm thick copper foil was laminated on the surface of an insulating base material made of 25 μm thick polyimide to form a conductor layer. The size of the circuit pattern was 50 μm × 50 μm. Furthermore, five printed wiring boards each having the structure of Example 1 and each comparative example were prepared, and aligned with the printed wiring board for the lowermost layer to laminate, thereby producing a six-layer multilayer wiring board.

  Further, as a cooling / heating cycle test, a process of leaving at −40 ° C. for 30 minutes and then leaving at 125 ° C. for 30 minutes was defined as one cycle, and a thermal shock was repeated 1000 times. Then, the resistance value change rate between the conductor layer and the conductive paste layer (interlayer connection portion) was confirmed by a tester every cycle. This is because, as the crack generated in the interlayer connection grows, the rate of change in resistance value due to electrical continuity failure also increases, so the degree of crack growth in the interlayer connection is verified by examining the rate of change in resistance value. To do. The test results are shown in FIG.

  In this test, the resistance value change rate after 1000 cycles was 37% for the resistance value of Comparative Example 1, 48% for the resistance value of Comparative Example 2, and 29% for the resistance value of Comparative Example 3. It became. On the other hand, in the multilayer wiring board of Example 1, it was found that the rate of change in resistance value after 1000 cycles was as small as 8%. This is probably because a plurality of different types of alloy layers were formed at the connection interface between the conductor layer 12 and the conductive paste layer 15, so that crack growth due to material expansion / contraction was suppressed at the interlayer connection portion. Is done.

[Test 2]
Here, as Example 2, as shown in FIG. 6B of Embodiment 3, one layer of the first conductive paste 16 is formed, and one layer of the second conductive paste 17 is formed on the inside thereof. A multilayer wiring board having a structure in which the first conductive paste 16 was formed was prepared. The contents of Comparative Examples 1 to 3 and the cooling and cycling test are the same as in Test 1. The test results are shown in FIG.

  In this test, the resistance change rate of Comparative Examples 1 to 3 is the same as Test 1. The multilayer wiring board of Example 2 was found to have a very small resistance value change rate of 2% after 1000 cycles. This is because a plurality of different types of alloy layers are formed at the connection interface between the conductor layer 12 and the conductive paste layer 15 as compared with the first embodiment, so that cracks due to material expansion / contraction occur in the interlayer connection portion. It is surmised that this growth was further suppressed than in Example 1.

1 is a partial cross-sectional view of a multilayer wiring board according to Embodiment 1. FIG. It is the elements on larger scale of FIG. (A)-(i) is process drawing which shows the manufacturing method of the multilayer wiring board concerning Embodiment 1. FIG. (J)-(l) is process drawing which shows the manufacturing method of the multilayer wiring board concerning Embodiment 1. FIG. (A)-(e) is a schematic diagram which shows the filling process of the electrically conductive paste layer in Embodiment 2. FIG. (A), (b) is a schematic diagram which shows the filling process of the electrically conductive paste layer in Embodiment 3. FIG. It is a graph which shows the result of the test 1 in an Example. It is a graph which shows the result of the test 2 in an Example. It is a fragmentary sectional view of the IVH part in the conventional multilayer wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Printed wiring board 11 ... Insulation base material 12 (12a, 12b) ... Conductor layer 13 ... Adhesive material layer 14 ... Via hole (interlayer conduction hole)
DESCRIPTION OF SYMBOLS 15 ... Conductive paste layer 15a ... Protrusion part 16 ... 1st conductive paste (conductive composition)
16a, 17a, 18a, 18 ... alloy layer 17 ... second conductive paste (conductive composition)
19 ... Masking film 20 ... Laminate (insulating layer)
DESCRIPTION OF SYMBOLS 21 ... Through-hole 22 ... Squeeze plate 30 ... Printed wiring board 40 ... Multilayer wiring board 41 ... Insulating film

Claims (4)

First and second conductor layers are disposed on both sides of the insulating layer, and the first and second conductor layers are electrically connected by a layer of a conductive composition filled in an interlayer conduction hole formed in the insulating layer. Multi-layered wiring board,
A plurality of connection interfaces extending in the depth direction of the interlayer conduction holes are formed, and a plurality of types of conductive compositions are filled in layers along the radial direction of the interlayer conduction holes,
The conductive composition layer includes a first conductive composition layer, a second conductive composition layer, a first conductive metal in the first conductive composition, and a second conductive composition. And a layer made of an alloy layer containing an alloy with the second conductive metal in the conductive composition. An insulating layer having an insulating base material and an adhesive layer laminated to each other, and having an interlayer conduction hole;
A plurality of connection interfaces extending in the depth direction of the interlayer conduction holes are formed, and a layer of a conductive composition filled in layers along the radial direction of the interlayer conduction holes;
A first conductor layer formed at a position of the interlayer conduction hole on the surface of the insulating layer on the insulating substrate side and electrically connected to the conductive composition;
A second conductor layer formed at a position of the interlayer conduction hole on the surface of the insulating layer on the adhesive layer side and electrically connected to the conductive composition;
Have
The conductive composition layer includes a first conductive composition layer, a second conductive composition layer, a first conductive metal in the first conductive composition, and a second conductive composition. And a layer made of an alloy layer containing an alloy with the second conductive metal in the conductive composition. A wiring in which a conductor layer is disposed on both sides of an insulating layer having an insulating base and an adhesive layer, and a conductive composition for electrically connecting the conductor layers to the interlayer conductive holes formed in the insulating layer is filled A method for producing a multilayer wiring board obtained by laminating boards,
Forming an adhesive layer and a mask layer on the surface opposite to the conductor layer of the insulating base provided with a conductor layer on one side;
Forming an interlayer conduction hole having the conductor layer as a bottom in the insulating base;
Filling a plurality of types of conductive compositions in layers along the radial direction of the interlayer conduction holes so that a plurality of connection interfaces extending in the depth direction of the interlayer conduction holes are formed;
Removing the mask layer to expose the adhesive layer and the end of the conductive composition;
Laminating and thermocompression bonding a plurality of wiring boards including the wiring board produced through the above steps;
A method for producing a multilayer wiring board, comprising: Comprising a step of forming a through hole having a diameter smaller than the diameter of the interlayer conduction hole in the conductor layer serving as the bottom of the interlayer conduction hole;
In the step of filling the conductive composition, the outside of the through hole is set to a negative pressure, a part of the conductive composition introduced from the upper part of the interlayer conductive hole is pulled out from the through hole, and the remaining the Forming a conductive composition on a sidewall of the interlayer conduction hole;
The method for producing a multilayer wiring board according to claim 3.

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