JP2009231414A - Multilayer wiring board, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer wiring board having good dimensional accuracy and suppressed intrusion of moisture into the board; and a manufacturing method thereof. <P>SOLUTION: This multilayer wiring board is provided with: an insulating base 1 including two kinds of glass ceramic insulation layers with burning shrinkages started at temperatures different from each other, and formed by stacking first glass ceramic insulation layers 11a-11e with burning shrinkage started at the low-temperature side and second glass ceramic insulation layers 12a-12d with burning shrinkage started at the high-temperature side relative to the first glass ceramic insulation layers 11a-11e to contact one another; through conductors 4 formed by penetrating through the first glass ceramic insulation layers 11a and 11e constituting surface layers; and land conductors 2 formed on the surfaces of the insulating base 1 and connected to the through conductors 4. The multilayer wiring board is characterized in that the land conductor 2 is composed of a land body 21 and an annular projection part 22 projecting toward the inside of the insulating base 1 from the land body 21 to surround the through conductor 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a multilayer wiring board that suppresses firing shrinkage in a planar direction by laminating and firing two types of glass ceramic green sheets that start firing shrinkage at different temperatures, and a method for manufacturing the same.

  Conventionally, in a multilayer wiring board used in the field of mobile communication, etc., gold, silver, copper, aluminum or a mixture thereof having a high conductivity is used as a wiring layer material, and a melting point of the wiring layer material as an insulating layer material The thing using the glass ceramics which can be baked at a temperature lower than this is known.

  In this multilayer wiring board, the wiring layer and the wiring layer are electrically connected by a through conductor penetrating the inside of the insulating layer. As a manufacturing method, a through hole is formed in a glass ceramic green sheet, and a conductive paste serving as a through conductor is filled in the through hole, and a conductor paste serving as a land conductor and a wiring layer is formed on one main surface of the glass ceramic green sheet. Examples thereof include a method of printing by a screen printing method or the like, and laminating a plurality of glass ceramic green sheets thus produced and firing. Here, the land conductor is one of the insulating layers in order to improve the connection between the through conductor, the through conductor, the connection between the through conductor and the wiring layer, and the connection between the through conductor and the surface mount component. It is a conductor layer formed on the surface connected to the through conductor, and is formed in a disk shape, for example.

  By the way, the volume of the glass ceramic green sheet laminate for forming a multilayer wiring board using glass ceramics shrinks by about 40 to 50% by firing shrinkage (sintering). At this time, the shrinkage rate in the direction (plane direction) perpendicular to the laminating direction of the glass ceramic green sheet laminate varies in average about 15 to 20% in one direction. Due to this variation, the dimensional accuracy of the multilayer wiring board is poor. It was.

Therefore, as a method for improving the dimensional accuracy of the multilayer wiring board, two or more types of ceramic green sheets having different firing shrinkage start temperatures and firing shrinkage end temperatures (in the case of two types, the first glass ceramic insulating layer and the second layer after firing) And a method of suppressing shrinkage in the planar direction and mainly shrinking in the laminating direction has been proposed (see, for example, Patent Document 1).
JP 2003-69236 A

  In the method described in Patent Document 1, the firing shrinkage start temperature and firing shrinkage end temperature of the first glass ceramic green sheet that becomes the first glass ceramic insulating layer after firing, and the second glass ceramic insulating layer after firing. Since the firing shrinkage start temperature and firing shrinkage end temperature of the second glass ceramic green sheet are different, the shrinkage in the planar direction is restrained and restrained. For example, when the second glass ceramic green sheet starts firing shrinkage (sintering) after the firing shrinkage (sintering) of the first glass ceramic green sheet, the first glass ceramic green sheet is At the time of firing shrinkage, the second glass ceramic green sheet has not started firing shrinkage, so that shrinkage in the planar direction of the first glass ceramic green sheet is suppressed. On the other hand, at the time of firing shrinkage (sintering) of the second glass ceramic green sheet, the first glass ceramic green sheet has already finished firing shrinkage by the first glass ceramic insulating layer. Shrinkage in the plane direction is suppressed. In this way, the glass ceramic green sheets are constrained to each other, so that the shrinkage in the planar direction is reduced, and the shrinkage variation in the planar direction can be reduced.

  However, since the conductor pastes (penetrating conductors) formed on the respective glass ceramic green sheets and in direct contact with each other are made of the same material, they are not constrained to each other and contract in the planar direction. Therefore, a large difference occurs in the shrinkage rate between the glass ceramic green sheet and the conductive paste (through conductor).

  Conventionally, there has been a problem that a gap is formed between the through conductor and the glass ceramic insulating layer due to the difference in shrinkage rate. Further, with the shrinkage of the conductor paste that becomes the through conductor, the conductor paste that becomes the land conductor shrinks so as to be pulled by the conductor paste that becomes the through conductor, and at the interface between the land conductor and the glass ceramic insulating layer after firing. However, there was a problem that the shear stress worked and a gap was formed. Due to the formation of such a gap, as a result, there is a problem that moisture such as a plating solution infiltrates from the surface of the multilayer wiring board into the interior, thereby reducing the reliability of the multilayer wiring board.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a multilayer wiring board with good dimensional accuracy and suppressed moisture permeation into the board, and a method for manufacturing the same.

  As a result of intensive studies, the present inventor has determined that the intrusion route does not penetrate from the surface to the inside even if a gap is formed between the through conductor and the glass ceramic insulating layer. As a result, the present invention has been achieved.

  That is, the present invention includes two types of glass ceramic insulating layers that have started firing shrinkage at different temperatures, the first glass ceramic insulating layer that has started firing shrinkage on the low temperature side, and a temperature higher than that of the first glass ceramic insulating layer. Insulation in which the first glass ceramic insulating layer or the second glass ceramic insulating layer constitutes a surface layer, and is laminated so as to be in contact with the second glass ceramic insulating layer that starts firing shrinkage on the side A base, a penetrating conductor formed through the first glass ceramic insulating layer or the second glass ceramic insulating layer constituting at least a surface layer of the insulating base, and a surface formed on the surface of the insulating base. A multi-layer wiring board including a land conductor connected to the through conductor, wherein the land conductor surrounds the land body and the through conductor. And it is characterized in that comprising a ridge portion of the annular protruding toward the inside of the insulating base from the land body.

  The present invention also provides a first glass ceramic green sheet containing a first glass powder that starts firing shrinkage on a low temperature side and a second glass ceramic green sheet containing a second glass powder that starts firing shrinkage on a high temperature side. And a first glass ceramic green sheet that is disposed on at least a surface layer of the laminate when producing a laminate including the first glass ceramic green sheet and the second glass ceramic green sheet. Alternatively, the first glass ceramic green sheet or the second glass ceramic is formed in the second glass ceramic green sheet by forming a through hole, filling the through hole with a conductive paste, and disposed at least on the surface layer of the laminate. An annular groove surrounding the through hole is formed on one main surface of the green sheet. A step of filling the annular groove with the conductive paste, and then applying the conductive paste from the upper side of the through hole to at least the upper side of the annular groove; a first glass ceramic green sheet and a second glass ceramic green Laminating the sheet so as to be in contact with the sheet, and producing a laminate having the one main surface of the first glass ceramic green sheet or the second glass ceramic green sheet disposed on the surface layer as a surface; And a step of firing the laminated body.

  According to the multilayer wiring board of the present invention, the land conductor formed on the surface of the insulating base is directed from the land main body toward the inside of the insulating base so as to surround the land main body and the through conductor connected to the land main body. Since it has a structure consisting of protruding annular ridges, there is no gap formed between the side wall on the through conductor side (inner diameter side) of the annular ridge and the glass ceramic insulating layer, A highly reliable multilayer wiring board in which moisture intrusion is suppressed can be realized.

  Further, according to the method for manufacturing a multilayer wiring board of the present invention, the conductor paste filled in the annular groove formed in the glass ceramic green sheet is drawn toward the side of the green sheet on the conductor paste side (inner diameter side) serving as a through conductor. As a result, the gap is not formed between the side wall on the through conductor side (inner diameter side) of the annular protrusion provided on the land conductor and the glass ceramic insulating layer. A highly reliable multilayer wiring board in which moisture permeation is suppressed can be manufactured.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view of an embodiment of a multilayer wiring board according to the present invention. The multilayer wiring board shown in FIG. 1 includes first glass ceramic insulating layers 11a to 11e made of different glass ceramics and second glass. Insulating substrate 1 in which ceramic insulating layers 12a to 12d are alternately laminated, surface wiring layer 3a formed on the surface of insulating substrate 1, internal wiring layer 3b formed inside insulating substrate 1, and insulating substrate 1 In this configuration, a through conductor 4 formed so as to penetrate at least the first glass ceramic insulating layers 11a and 11e constituting the surface layer and a land conductor 2 connected to the through conductor 4 are provided.

  The first glass ceramic insulating layers 11a, 11b, 11c, 11d, 11e and the second glass ceramic insulating layers 12a, 12b, 12c, 12d constituting the insulating base 1 have different firing shrinkage start temperatures and firing shrinkage end temperatures. Each glass ceramic green sheet is sintered. The firing shrinkage start temperature and firing shrinkage end temperature of the second glass ceramic green sheet for forming the second glass ceramic insulation layers 12a, 12b, 12c, 12d are the first glass ceramic insulation layers 11a, 11b, 11c. , 11d and 11e are set to be higher than the firing shrinkage start temperature and firing shrinkage end temperature of the first glass ceramic green sheet. Desirably, the firing shrinkage start temperature of the second glass ceramic green sheet is higher than the firing shrinkage end temperature of the first glass ceramic green sheet, in other words, the first glass ceramic green sheet undergoes firing shrinkage. The second glass ceramic green sheet is set to start firing shrinkage after completion.

Specifically, in selecting the glass ceramic material, the crystallization temperature of the glass contained in the first glass ceramic green sheet is selected to be lower than the softening point of the glass contained in the second glass ceramic green sheet. ing. The simplest method for achieving this is to vary the softening point of the glass by varying the glass composition. In addition, it can also be achieved by varying the amount ratio of glass and filler, or by adding a nucleating agent such as TiO ₂ , CeO ₂ , or SnO as the third additive. As a result, when the second glass ceramic green sheet starts firing shrinkage, the firing shrinkage of the first glass ceramic green sheet is finished, and the shrinkage in the planar direction of each other can be suppressed.

  Here, the firing shrinkage start temperature is defined as the temperature at which the volume shrinks by 0.3% when the target material is fired alone. Moreover, the completion | finish temperature of baking shrinkage here means the temperature when 90% or more of volume shrinkage | contraction with respect to the shrinkage | contraction amount from the state before baking to the state after completion | finish of baking. The volume shrinkage is determined by converting the linear shrinkage of TMA (thermomechanical analysis) into volume shrinkage.

  The insulating substrate 1 (first glass ceramic insulating layers 11a, 11b, 11c, 11d, 11e and second glass ceramic insulating layers 12a, 12b, 12c, 12d) is 30% by mass or more of crystallized glass, and further 40 It is preferable from a viewpoint of sinterability to contain -90 mass%, especially 50-80 mass%. Of the crystallized glass contained in the insulating substrate 1 (the first glass ceramic insulating layers 11a, 11b, 11c, 11d, 11e and the second glass ceramic insulating layers 12a, 12b, 12c, 12d), the amount of residual glass (Amorphous part that is not crystallized) is 10% by mass or less, more preferably 5% by mass or less, and particularly 2% by mass or less. Desirable from a viewpoint. The residual glass amount can be determined from the XRD diffraction pattern by Rietveld analysis. Further, the glass can be determined by a program analysis in which a sample and ZnO (standard sample) are mixed at a predetermined ratio and all crystal phases formed on the sample and a ZnO standard sample are taken into consideration.

Specifically, the insulating substrate 1 (first glass ceramic insulating layers 11a, 11b, 11c, 11d, 11e and second glass ceramic insulating layers 12a, 12b, 12c, 12d) is made of crystallized glass and an inorganic filler. As the crystallized glass composed of diopside, hardestite, celsian, cordierite, anorthite, garnite, willemite, spinel, mullite, forsterite, and sourite preferable. Of these crystals, diopside, hardestite, celsian, willemite and forsterite are desirable in terms of dielectric properties, and diopside, celsian, cordierite and anorthite are desirable in terms of strength, and dielectric properties and strength. In this respect, diopside and celsian are desirable. The inorganic _{filler, Al 2 O 3, SiO 2} , MgTiO 3, CaZrO 3, CaTiO 3, Mg 2 SiO 4, BaTi 4 O 9, ZrTiO 4, SrTiO 3, BaTiO 3, TiO 12a lN, Si 3 N ₄ etc. can be illustrated. Among these, Al ₂ O ₃ , MgTiO ₃ , CaZrO ₃ , CaTiO ₃ , Mg ₂ SiO ₄ , and BaTi ₄ O ₉ are desirable in terms of dielectric characteristics, and Al ₂ O ₃ , AlN, Si ₃ N _{4 in} terms of strength. Al ₂ O ₃ is desirable in terms of dielectric properties and strength.

  The insulating substrate 1 (first glass ceramic insulating layers 11a, 11b, 11c, 11d, 11e and second glass ceramic insulating layers 12a, 12b, 12c, 12d) composed of such crystallized glass and inorganic filler is It can be produced by firing at a temperature of 1000 ° C. or lower.

  The first glass ceramic insulating layers 11a, 11b, 11c, 11d, and 11e and the second glass ceramic insulating layers 12a, 12b, 12c, and 12d have different firing shrinkage (sintering) behavior in the manufacturing process. However, not only this difference but also other characteristics such as relative dielectric constant, bending strength, dielectric loss, thermal conductivity, bulk density, and temperature coefficient may be different depending on the purpose.

Further, the difference in thermal expansion coefficient at 0 to 100 ° C. between the first glass ceramic insulating layers 11a, 11b, 11c, 11d, and 11e and the second glass ceramic insulating layers 12a, 12b, 12c, and 12d is 2 × 10 ^{−. It} is preferably ⁶ / ° C. or lower, particularly 1 × 10 ⁻⁶ / ° C. or lower. Within this range, in the temperature lowering process from the maximum firing temperature, at the interface between the first glass ceramic insulating layers 11a, 11b, 11c, 11d and 11e and the second glass ceramic insulating layers 12a, 12b, 12c and 12d. This is because the risk of cracks and delamination is reduced.

  Furthermore, in the present embodiment, the first glass ceramic insulating layer and the second glass ceramic insulating layer are alternately laminated. However, these do not necessarily have to be alternated, and at least the upper side or the lower side is not necessarily required. The glass ceramic insulating layer which has started firing shrinkage at different temperatures may be disposed on the side. Specifically, even if the layer immediately below the first glass ceramic insulating layer is the first glass ceramic insulating layer, the layer immediately above the first glass ceramic insulating layer is the second glass ceramic insulating layer. If it is. In addition, the layer which is arrange | positioned inside a surface layer (the uppermost layer and the lowest layer) and touches the said surface layer turns into a glass-ceramic insulating layer which started baking shrinkage at the temperature different from a surface layer.

  On the other hand, the surface wiring layer 3a, the internal wiring layer 3b, the through conductor 4, and the land conductor 2 (land main body 21, annular protrusion 22) are formed of a low resistance conductor mainly composed of Cu, Ag, Al or the like. ing. The insulating substrate 1 (first glass ceramic insulating layers 11a, 11b, 11c, 11d, 11e and second glass ceramic insulating layers 12a, 12b, 12c, 12d) can be manufactured by firing at a temperature of 1000 ° C. or less. Therefore, it is possible to use a low-resistance conductor mainly composed of Cu, Ag, etc. as a conductor material for forming the surface wiring layer 3a, the internal wiring layer 3b, the through conductor 4, and the land conductor 2, thereby realizing high-speed transmission. . The conductive material may contain inorganic components such as other metals, oxides, glass, ceramics, etc. within a range that does not deteriorate the electrical resistance and thermal conductivity with respect to these main components. Further, the surface wiring layer 3a, the internal wiring layer 3b, the land main body 21, the through conductor 4, and the annular protrusion 22 have different manufacturing methods depending on the application and filling. For example, glass, inorganic filler, etc. The subcomponents may be different.

  In the land conductor 2, a poor connection between the through conductors 4 or a poor connection between the through conductor 4 and the wiring layer (surface wiring layer 3 a, internal wiring layer 3 b) occurs due to a stacking deviation or the like. In order to prevent the occurrence of poor connection, the connection conductor 4 is formed to be connected.

  The insulating substrate 1 is formed so as to penetrate at least the first glass ceramic insulating layer or the second glass ceramic insulating layer (in this embodiment, the first glass ceramic insulating layers 11a and 11e) constituting the surface layer. The land conductor 2 connected to the through conductor 4 and formed on the surface of the insulating base 1 protrudes from the land main body 21 toward the inside of the insulating base 1 so as to surround the land main body 21 and the through conductor 4. It is important to consist of the strip 22.

  The land conductor 2 formed on the surface of the insulating base 1 is directed from the land body 21 toward the inside of the insulating base 1 so as to surround the through conductor 4 formed in the first glass ceramic insulating layers 11a and 11e as the surface layer. By having the projecting annular protrusion 22, moisture such as a plating solution is prevented from entering the inside of the multilayer wiring board from the inside, and a highly reliable multilayer wiring board is obtained.

  This is because, conventionally, a large difference in shrinkage ratio occurs between the conductive paste that becomes a through conductor after firing and the glass ceramic green sheet, and a gap is formed between the fired glass ceramic insulating layer and the through conductor. As a result, the conductor paste that becomes the land conductor shrinks so as to be pulled by the conductor paste that becomes the through conductor, and a gap is formed between the land conductor after firing and the glass ceramic insulating layer, resulting in plating. There has been a problem that moisture such as liquid enters the inside from the surface of the multilayer wiring board and the reliability of the multilayer wiring board decreases. On the other hand, an annular groove is formed so as to surround the through-hole in the manufacturing stage, and this annular groove is filled with a conductive paste that becomes the annular protrusion 22, so that this annular protrusion is fired. Since the conductor paste that becomes the portion 22 shrinks in such a manner that both the inner diameter and the outer diameter become smaller, the glass ceramic green that exists between the conductor paste that becomes the through conductor 4 and the conductor paste that becomes the protruding portion 22. This is because stress that tightens the sheet is generated, and no gap is generated between the inner diameter side wall surface 221 of the annular protrusion 22 after firing and the glass ceramic insulating layer.

  Further, according to this configuration, the glass ceramic green sheet existing between the conductor paste to be the through conductor 4 and the conductor paste to be the annular protrusion 22 is formed into the conductor paste and the land to be the annular protrusion 22. In order to generate stress so as to prevent contraction of the conductor paste that becomes the main body 21 toward the penetrating conductor, it is suppressed from being contracted so as to be pulled by the conductor paste that becomes the penetrating conductor, and as a result, the land conductor 2 after firing And the formation of a gap between the glass ceramic insulating layers (11a to 11e, 12a to 12d) can be suppressed.

  The land body 21 is generally formed in a disk shape, but the shape is not particularly limited. Further, the annular protrusion 22 may be provided so as to protrude from any position of the land main body 21 as long as it does not come into contact with the through conductor 4. From the viewpoint of stress relaxation, it is preferably provided so as to protrude from the vicinity of the outer periphery.

  The width and height of the annular ridge 22 are preferably thicker and higher in terms of suppressing the formation of gaps, but the conductor paste is filled in the annular groove during manufacturing. In consideration of the characteristics and high-frequency signal transmission properties, the width is preferably 15 to 50 μm and the height is preferably 15 to 50 μm.

  Furthermore, in order to enhance the effect of suppressing the formation of a gap between the fired glass ceramic insulating layer and the through conductor, as shown in FIG. 22 is preferably provided.

  With the above configuration, a gap is not formed between the through conductor side wall surface (inner diameter side wall surface 221) of the annular protrusion 22 and the glass ceramic insulating layer, and the moisture intrusion into the interior is suppressed. A multilayer wiring board with high performance can be realized.

  Next, a method for manufacturing the multilayer wiring board will be described.

  First, a first glass ceramic green sheet containing a first glass powder that starts firing shrinkage at a different temperature and starts firing shrinkage at a low temperature side, and a second glass powder containing a second glass powder that starts firing shrinkage at a high temperature side. 2 glass ceramic green sheets are prepared.

As the first glass ceramic green sheet containing the first glass powder that starts firing shrinkage on the low temperature side that becomes the first glass ceramic insulating layers 11a, 11b, 11c, 11d, and 11e after firing, for example, SiO ₂ is used. and 10 to 30 wt%, and the _Al 2 _{O 3} 1 to 9 wt%, and 5 to 30 wt% of MgO, and 21 to 35 wt% of _BaO, and the B 2 _{O 3} 10 to 30 wt%, Y _{2 O 3, CaO, SrO,} ZnO, TiO 2, Na 2 O, 40~90 mass consisting of at least one of 0 to 20 wt% selected from _{SnO 2, P 2 O 5,} ZrO 2 and Li ₂ O % glass _{powder, Al 2 O 3, SiO 2} , MgTiO 3, CaZrO 3, CaTiO 3, BaTi 4 O 9, SrTiO 3, ZrO 2, TiO 2, AlN and Si Raw material powder composed of 10 to 60 wt% of ceramic filler containing at least one selected from N ₄ is employed.

On the other hand, as the second glass ceramic green sheet containing the second glass powder that starts firing shrinkage on the high temperature side that becomes the second glass ceramic insulating layers 12a, 12b, 12c, 12d after firing, for example, SiO ₂ and 20 to 60 wt%, _Al 2 and _{O 3} 10 to 25 wt%, the MgO 8 to 35 wt%, and 10 to 20 wt% of _{BaO, B 2 O 3, Y} 2 O 3, CaO, SrO, At least one selected from Na ₂ O, SnO ₂ , P ₂ O ₅ , ZrO ₂ and Li ₂ O, 30 to 100% by mass of glass powder, Al ₂ O ₃ , SiO _{2 , MgTiO 3, CaZrO 3, CaTiO} 3, BaTi 4 O 9, SrTiO 3, 0 comprising _{the ZrO 2,} TiO _{2, AlN,} at least one selected from _Si 3 _{N 4} Raw material powder is employed comprised of a 70 wt% ceramic filler.

  The first glass ceramic green sheet and the second glass ceramic green sheet are slurries obtained by mixing the raw material powder with a volatile organic binder and an organic solvent that easily volatilize during firing, and, if necessary, a plasticizer. This slurry is used to form a tape by a lip coater method, a doctor blade method, or the like, and cut into a predetermined size.

  At this time, one glass ceramic green sheet and one glass ceramic green sheet may be thermocompression bonded to produce a composite glass ceramic green sheet. And the annular groove are formed after the composite glass ceramic green sheet is produced. In this case, either one of the first glass ceramic green sheet and the second glass ceramic green sheet may be pasted (insulator paste).

  Next, when the laminated body containing the 1st glass ceramic green sheet and the 2nd glass ceramic green sheet is produced, the 1st glass ceramic green sheet or 2nd glass ceramic arrange | positioned at least on the surface layer of a laminated body A through hole is formed in the green sheet, and the through hole is filled with a conductive paste. Also, a conductor paste is applied to one main surface of the first glass ceramic green sheet or the second glass ceramic green sheet disposed on at least the surface layer of the laminate from the upper side of the through hole to at least the upper side of the annular groove. Apply.

  Specifically, the formation of through holes in the first glass ceramic green sheet or the second glass ceramic green sheet disposed in at least the surface layer (the uppermost layer and the lowermost layer) of the laminate formed later is punching, It is performed by a method such as laser or etching. Here, a through hole is formed on one main surface of the first glass ceramic green sheet or the second glass ceramic green sheet disposed in at least the surface layer (the uppermost layer and the lowermost layer) of the laminate formed later. At the same time, an annular groove surrounding the through hole is formed. When the through hole is formed by punching, it includes a pin for forming the through hole, a disk-like portion fixed perpendicularly to the root of the pin, and an annular ridge protruding from the disk-like portion. By preparing and punching a mold having a substantially T-shaped section, a through-hole and an annular groove can be simultaneously formed in the glass ceramic green sheet. Further, when the through hole is formed with a laser, an annular groove can be formed with a laser by suppressing the output or the number of shots as compared with the formation of the through hole.

  Then, the conductor paste is filled into the through hole and the annular groove. As a conductive paste, an organic binder, an organic solvent, and, if necessary, an organic or inorganic additive added to gold powder, silver powder, copper powder, or aluminum powder, and kneaded with three rolls Is used. For the filling, a screen printing method is used by using a metal mask or an emulsion mesh screen mask perforated at a position corresponding to the through conductor forming position. At this time, as a method for extruding the conductor paste through the mask, a method using a normal polyurethane plate-like (or sword-like) squeegee may be used, and a method of pressurizing and injecting the paste using a paste extrusion type squeegee head But you can. Further, the viscosity of the conductor paste and the printing conditions are adjusted, and the filled conductor paste is overfilled so as to protrude from the surface of the ceramic green sheet on the through hole and the annular groove. Thereafter, the protruding conductor paste is pressed and pushed in as necessary.

  Further, a conductor paste that becomes the surface wiring layer 3a, the internal wiring layer 3b, and the land body 21 is applied by a screen printing method or the like. As a conductive paste, an organic binder, an organic solvent, and, if necessary, an organic or inorganic additive added to gold powder, silver powder, copper powder, or aluminum powder, and kneaded with three rolls Is used. The conductor paste used here has a viscosity different from that of the conductor paste filled in the through-holes and the annular grooves, for example, by means such as varying the amount of the organic solvent. Specifically, by making the viscosity lower than that of the conductor paste filled in the through holes and the annular grooves, the thickness can be reduced and an accurate pattern can be formed. On the other hand, the conductive paste filled in the through holes and the annular grooves has a high viscosity so that it does not sag after filling.

  Each glass ceramic green sheet obtained in this way is laminated according to a predetermined lamination order to form a laminate. Specifically, the first glass ceramic green sheet or the second glass ceramic green sheet is laminated so that the first glass ceramic green sheet and the second glass ceramic green sheet are in contact with each other and arranged on the surface layer. A laminate having one main surface as a surface is produced.

  Finally, the laminate is fired. If desired, heat treatment is performed at 100 to 800 ° C., particularly 400 to 750 ° C. to decompose and remove the organic components in the laminate, and then it is sufficiently sintered and prevented from oversintering, particularly 800 to 1000 ° C. Bake at 850-950 ° C.

  By such a manufacturing method, the conductive paste filled in the annular groove formed in the glass ceramic green sheet shrinks by firing so as to be drawn to the side of the green sheet on the conductor paste side (inner diameter side) serving as a through conductor. In addition, there is no gap formed between the side wall on the through conductor side (inner diameter side) of the annular ridge provided on the land conductor and the glass ceramic insulating layer, and the reliability of moisture penetration is suppressed. A multilayer wiring board having a high level can be obtained.

First, as the raw material powder for forming the first glass ceramic green sheet that becomes the first glass ceramic insulating layer after firing, 23.8% by mass of SiO ₂ , 8.4% by mass of Al ₂ O ₃ , 15.4 mass% of MgO, 26.5 wt% of BaO, 17.9 wt% of _B 2 _O 3, 4.9 wt% of CaO, 0.4 wt% of SrO, _SnO 2 of 1.0 wt%, 1 A material composed of 60% by mass of glass powder composed of 0.7% by mass of ZrO ₂ and 40% by mass of Al ₂ O ₃ filler was prepared.

Further, as the raw material powder for forming the second glass-ceramic green sheets serving as the second glass-ceramic insulating layer after firing, 43.3 wt% of _SiO 2, 12.9 wt% of _Al 2 _O 3, 18.0 mass% of MgO, 14.1 wt% of BaO, 7.5 wt% of _B 2 _O 3, 1.0 wt% of _Y 2 _O 3, 1.7 wt% of CaO, 0.5 wt% of SrO A glass powder composed of 60% by mass of ZrO ₂ and 1.0% by mass of ZrO ₂ and 40% by mass of Al ₂ O ₃ filler was prepared.

  Acrylic organic binder, plasticizer, and organic solvent are added to each raw material powder to produce a slurry, which is made into a thin layer by a doctor blade method to produce a first glass ceramic green sheet and a second glass ceramic green sheet. did. At this time, the thickness of the first glass ceramic green sheet was prepared to be 37 μm after firing. The second glass ceramic green sheet was prepared to have a thickness of 74 μm.

  In addition, one glass ceramic green sheet and one second glass ceramic green sheet were thermocompression bonded to produce a composite glass ceramic green sheet.

  Next, beta quartz, barium borosilicate glass and organic vehicle are added to the silver powder, and these are stirred and then mixed with a three-roll mill until there is no aggregate of silver powder and organic binder. Produced. The organic vehicle was composed of 5% by mass of ethyl cellulose as an organic binder and 95% by mass of α-terpineol as an organic solvent, and 15 parts by mass of this organic vehicle was added to 100 parts by mass of silver powder.

  Next, through holes were formed by punching in order to form through conductors in the first glass ceramic green sheet, the second glass ceramic green sheet, and the composite glass ceramic green sheet. In addition, the cyclic | annular groove | channel was formed simultaneously with the through-hole using the metal mold | die of the structure which has the cyclic | annular protrusion part which forms an annular groove around the pin for forming a through-hole.

  Next, the above-mentioned conductor paste was filled in the through holes and the annular grooves. An on-contact printer equipped with a paste extrusion head was used for filling the conductor paste.

  Also, a conductive paste serving as a surface wiring layer, an internal wiring layer, and a land body on the surface of the composite glass ceramic green sheet (first glass ceramic green sheet and second glass ceramic green sheet) and the first glass ceramic green sheet. Was deposited by screen printing. The viscosity is lower than that of the conductor paste filled in the through holes and the annular grooves.

  Next, the first glass ceramic green sheet, the second glass ceramic green sheet and the composite glass ceramic green sheet filled with the conductive paste are pressed with a flat plate mold, and the first glass ceramic green sheet and the second glass ceramic are pressed. A green sheet and a composite glass ceramic green sheet were laminated to produce a laminate, and a portion protruding from the surface of the conductor paste laminate was pushed into the through hole.

  At this time, the first glass ceramic green sheet is disposed as a surface layer (the uppermost layer and the lowermost layer), the second glass ceramic green sheet is disposed so as to contact the inside of the surface layer, and the first glass ceramic green sheet and the first glass ceramic green sheet The composite glass ceramic green sheets (the first glass ceramic green sheet and the second glass ceramic green sheet) and the first glass ceramic green sheet were combined so that the two glass ceramic green sheets were alternately arranged. Specifically, a laminate composed of a total of 9 layers of glass ceramic green sheets was formed using five first glass ceramic green sheets and four second glass ceramic green sheets.

  Thereafter, this laminate was subjected to binder removal treatment at 400 ° C. for 3 hours in the atmosphere, and further fired at 900 ° C. for 1 hour in the atmosphere, so that land conductors having annular protrusions having a height shown in Table 1 were formed on the surface. The provided multilayer wiring board was produced.

  And in the obtained multilayer wiring board, in order to investigate the presence or absence of moisture permeation to the periphery of the through conductor formed in the first glass ceramic insulating layer constituting the surface layer, 2 After vacuum-pressurizing for a period of time and wiping off the fluorescent flaw detection liquid on the surface, the upper surface was polished to remove the land body, and light emission under black light irradiation was observed with an optical microscope. The multilayer wiring board has 289 through conductors in the uppermost layer, and the measurement was performed on 12 multilayer conductors on a total of 3468 through conductors. The results are shown in Table 1.

  Sample No. In Nos. 1 to 6, the height of the annular ridges constituting the land conductor is changed to confirm whether or not the fluorescent flaw detection liquid has entered.

  Sample No. in which no ring-shaped protrusion is formed on the land conductor. In 1, the emission of fluorescent flaw detection liquid was observed in 210 (6.1%) with respect to 3468 through conductors, and it was confirmed that moisture permeation occurred.

  On the other hand, sample No. 1 in which an annular protrusion having a height of 5 to 10 μm was formed on the land conductor. In 2 and 3, it was confirmed that the fluorescence flaw detection liquid emits very little light.

  In particular, sample No. 1 in which an annular protrusion having a height of 15 to 25 μm was formed on the land conductor. In Nos. 4 to 6, it was confirmed that the fluorescence flaw detection liquid did not emit light and that no moisture had entered the periphery of the through conductor.

  From the above results, it can be seen that the emission rate of the fluorescent flaw detection liquid tends to decrease as the height of the annular ridge increases. This is thought to be due to an increase in the bonding area between the through-conductor side wall surface (inner diameter side wall surface) of the annular ridge formed on the land conductor and the glass ceramic insulating layer due to the height of the annular ridge. It is done.

It is a schematic sectional drawing of one Embodiment of the multilayer wiring board of this invention. It is a schematic sectional drawing of other embodiment of the multilayer wiring board of this invention, and has shown the structure by which the cyclic | annular protrusion was provided in all the land conductors.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulating base | substrate 11a, 11b, 11c, 11d, 11e 1st glass ceramic insulating layer 12a, 12b, 12c, 12d 2nd glass ceramic insulating layer 2 Land conductor 21 Land main body 22 Annular rib part 221 Inner diameter side wall surface 3a Surface wiring layer 3b Internal wiring layer 4 Through conductor

Claims (2)

It includes two types of glass ceramic insulating layers that have started firing shrinkage at different temperatures, the first glass ceramic insulating layer that has started firing shrinkage on the low temperature side, and the firing shrinkage on the higher temperature side than the first glass ceramic insulating layer An insulating substrate which is laminated so as to be in contact with the started second glass ceramic insulating layer, and at least the first glass ceramic insulating layer or the second glass ceramic insulating layer constitutes a surface layer; and the insulation A through conductor formed through the first glass ceramic insulating layer or the second glass ceramic insulating layer constituting at least a surface layer of the base, and a surface formed on the insulating base and connected to the through conductor A multi-layer wiring board provided with a land conductor, wherein the land conductor surrounds the land body and the through conductor so as to surround the land body. Multi-layer wiring board, characterized in that comprising a ridge portion of the annular protruding toward the inside of the insulating substrate. Producing a first glass ceramic green sheet containing a first glass powder that starts firing shrinkage on a low temperature side and a second glass ceramic green sheet containing a second glass powder starting firing shrinkage on a high temperature side; ,
The first glass ceramic green sheet or the second glass ceramic disposed in at least the surface layer of the laminate when the laminate including the first glass ceramic green sheet and the second glass ceramic green sheet is produced. A through hole is formed in the green sheet, the conductor paste is filled in the through hole, and one of the first glass ceramic green sheet or the second glass ceramic green sheet disposed on at least the surface layer of the laminate is provided. A step of forming an annular groove surrounding the through-hole on the surface and filling the annular groove with a conductive paste, and then applying the conductive paste from the upper side of the through-hole to at least the upper side of the annular groove. When,
The first glass ceramic green sheet or the second glass ceramic green sheet is laminated so that the first glass ceramic green sheet and the second glass ceramic green sheet are in contact with each other, and the first glass ceramic green sheet or the second glass ceramic green sheet disposed on the surface layer. Producing a laminate having a surface as a surface;
And a step of firing the laminated body.

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