JP2007115852A - Manufacturing method of ceramic substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a ceramic substrate capable of forming a bump electrode while suppressing contraction at baking. <P>SOLUTION: (1) A non-baked compound laminate is formed on one main surface of a non-baked ceramic substrate to which a confinement layer is tightly fitted with a non-baked bump electrode pattern that contains the metal material baked at the temperature for a hole forming material and non-baked ceramic substrate, in the base material that is not substantially baked at the temperature for non-baked ceramic substrate. (2) The non-baked compound laminate is baked at such temperature that the basic material of the confinement layer is not substantially baked, the hole forming material disappears, and the non-baked ceramic substrate as well as a metal material contained in the non-baked bump electrode pattern of the confinement layer are baked. (3) The base material of the confinement layer is removed to take out a ceramic substrate 15 comprising a bump electrode 18 on one main surface of a substrate body 16 where the non-baked bump electrode pattern is baked. The bump electrode 18 comprises a hole 18x formed from the hole forming material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a ceramic substrate, and more particularly to a method for manufacturing a ceramic substrate having a protruding electrode on one main surface.

  In order to increase the functionality, density, and performance of a multilayer ceramic substrate, it is effective to form wirings at a high density on the multilayer ceramic substrate. However, in the firing step for obtaining the multilayer ceramic substrate, the multilayer ceramic substrate is contracted and it is difficult to avoid variations in the shrinkage. For this reason, shrinkage, particularly shrinkage in the planar direction and variations thereof, are factors that hinder high-density wiring in the multilayer ceramic substrate. Under such a background, a so-called non-shrinking process has been proposed that can suppress shrinkage in a planar direction in a firing step for obtaining a multilayer ceramic substrate.

  In the non-shrink process, a plurality of ceramic green sheets for a substrate containing a ceramic material are prepared, and a ceramic green sheet for shrinkage suppression containing a ceramic that is not sintered at the firing temperature of the ceramic green sheet for a substrate is prepared. Then, a composite laminate is produced in which a ceramic green sheet for suppressing shrinkage is arranged so as to sandwich, for example, an unfired laminate for a substrate formed by laminating a plurality of ceramic green sheets for a substrate. On the other hand, a baking process is applied.

  In this firing step, only the substrate laminate is sintered so that the substrate laminate is a multilayer ceramic substrate, and the shrinkage-suppressing ceramic green sheet exists as a shrinkage-suppressing support in an unsintered state. By applying a force that suppresses firing shrinkage of the substrate laminate, that is, a restraining force, to the substrate laminate, shrinkage in the planar direction of the substrate laminate is suppressed.

As described above, according to the non-shrinkage process, it is difficult to cause shrinkage in the planar direction of the laminate for a substrate, so that the dimensional accuracy in the planar direction of the obtained multilayer ceramic substrate can be increased. It is possible to advantageously increase the density of wiring in (see, for example, Patent Document 1).
JP 2001-111223 A

  If components such as capacitors, resistors, and ICs are mounted on both main surfaces of such a multilayer ceramic substrate and mounted on a printed wiring board, the density can be increased easily. At this time, a predetermined interval is secured between the multilayer ceramic substrate and the printed wiring board so that components mounted on the main surface of the multilayer ceramic substrate facing the printed wiring board do not interfere with the printed wiring board. Therefore, it is conceivable to provide columnar protruding electrodes on the main surface of the multilayer ceramic substrate on the printed wiring board side.

  For example, a hole is formed in a specific ceramic green sheet for suppressing shrinkage, and the hole is filled with a conductive paste mainly composed of Ag. A green substrate laminate having a conductor pattern and vias is laminated to prepare an unfired laminate for a substrate to be a multilayer ceramic substrate. A ceramic green sheet for suppressing shrinkage in which a hole is filled with a conductive paste is laminated on one main surface of the unfired substrate laminate, and a ceramic green sheet for shrinkage suppression having no hole on the other main surface. Are laminated to produce a composite laminate. By firing the composite laminate, a protruding electrode obtained by sintering a conductive paste filled in a hole of a specific shrinkage-suppressing ceramic green sheet can be provided on one main surface of the multilayer ceramic substrate.

  The conductive paste that fills the holes in a specific shrinkage-constrained ceramic green sheet to provide a protruding electrode on one main surface of the ceramic multilayer substrate sinters and shrinks during firing of the composite laminate. In some cases, a dent (sink) occurs at the tip, or a gap is formed at the interface of each layer of a specific shrinkage-restraining ceramic green sheet, resulting in a so-called opening.

  That is, as shown in FIG. 12A, constraining layers 120 and 122 of an unfired ceramic green sheet for shrinkage suppression are provided on both main surfaces of an unfired laminated body 110 for an unfired board on which ceramic green sheets for a board are laminated. In the composite laminate 100, one constraining layer 122 is filled with a conductive paste in a hole to form an unfired ceramic green sheet for suppressing shrinkage formed as a protruding electrode, and unfired shrinkage suppressed without a hole. When the composite laminate 100 is fired, when the composite laminate 100 is fired, the portion 130 serving as the protruding electrode is fired and contracted with the side surface 132 and the tip surface 134 being constrained. 12 (b), at the interface of the shrinkage-suppressing ceramic green sheet on which the portion 130 to be the protruding electrode is formed, the so-called opening 1 There is that 6 occurs.

  Further, as shown in FIG. 13A, constraining layers 120 and 124 of unfired ceramic green sheets for suppressing shrinkage are provided on both main surfaces of the unfired laminated body for substrates 110 on which the ceramic green sheets for substrates are laminated. In the composite laminate 102, when one constraining layer 124 is composed only of an unfired ceramic green sheet for suppressing shrinkage in which a hole 130 is filled with a conductive paste to form a protruding electrode 130, this composite laminate When the portion 102 is fired, the portion 130 that becomes the protruding electrode is fired and contracted in a state where the side surface 132 is constrained. Therefore, after baking, as shown in FIG. A so-called dent 138 may occur.

  The dent at the tip of the protruding electrode and the opening at the middle position cause problems such as poor connection when the ceramic multilayer substrate is mounted on the printed wiring board.

  In view of such circumstances, the present invention intends to provide a method for manufacturing a ceramic substrate, which can form a protruding electrode while suppressing shrinkage during firing.

  In order to solve the above problems, the present invention provides a method for manufacturing a ceramic substrate configured as follows.

  The method for manufacturing a ceramic substrate includes first to third steps. In the first step, the pore forming material and the firing temperature of the unfired ceramic substrate in the base material that is not substantially sintered at the firing temperature of the unfired ceramic substrate are formed on one main surface of the unfired ceramic substrate. An unfired composite laminate is formed by adhering a constraining layer having an unfired bump electrode pattern containing a metal material to be sintered. In the second step, the base material of the constraining layer does not substantially sinter, the void forming material contained in the protruding electrode pattern of the constraining layer disappears, and the unfired ceramic substrate and The unfired composite laminate is fired at a temperature at which the metal material included in the unfired protruding electrode pattern of the constraining layer can be sintered. In the third step, the base material of the constraining layer is removed, and the main surface of the substrate body formed by firing the unsintered ceramic substrate is subjected to firing of the pattern for protruding electrodes of the constraining layer. The ceramic substrate having the protruding electrode formed is taken out. The protruding electrode includes a hole formed of the hole forming material included in the protruding electrode pattern of the constraining layer in the second step.

  According to the above method, when the pore forming material contained in the protruding electrode pattern of the constraining layer disappears due to the firing in the second step, the void is formed in the unfired protruding electrode pattern of the constraining layer. It is formed. Thereby, while suppressing shrinkage of the unfired protruding electrode pattern of the constraining layer during firing, the protruding metal can be formed by sintering the metal material in the unfired protruding electrode pattern of the constraining layer.

  The protruding electrode is preferably a columnar shape such as a substantially circular column or a substantially rectangular column, but may have a substantially conical shape, a truncated pyramid (approximately a truncated cone or a substantially truncated pyramid), or a substantially hemispherical shape. It is.

  Preferably, in the first step, the protruding electrode pattern fills a through hole provided in the base material of the constraining layer with a conductive paste containing the hole forming material and the metal material. Is formed.

  In this case, the pattern for protruding electrodes can be easily formed by printing the conductive paste by a printing method.

  Preferably, in the first step, the pore forming material is formed in such a ratio that the voids occupy 0.1 to 20% by volume of the protruding electrode in the third step. Included in.

  In this case, the ratio of the holes included in the protruding electrode can be made appropriate. That is, if the void content in the protruding electrode is less than 0.1% by volume, cracks occur between the substrate body of the ceramic substrate and the protruding electrode, and the void content exceeds 20% by volume. Since the conduction resistance of the protruding electrode tends to become extremely large, the content of voids is preferably 0.1 to 20% by volume.

  Preferably, the pore forming material contained in the conductive paste in the first step is selected so that the diameter of the pores is 0.1 to 10 μmφ in the third step. Yes.

  In this case, the dimension of the diameter of the hole contained in the protruding electrode can be made appropriate. That is, if the hole diameter is less than 0.1 μmφ, a crack occurs between the substrate body of the ceramic substrate and the protruding electrode, and if the hole diameter exceeds 10 μmφ, the conduction resistance of the protruding electrode is extremely large. Therefore, the pore diameter is preferably 0.1 to 10 μmφ.

  Preferably, the conductive paste includes a binder resin and a solvent. The pore forming material is resin beads that do not dissolve in the solvent.

  In this case, it is easy to form holes in the protruding electrodes.

  More preferably, the resin beads are mainly composed of polypropylene, and the polypropylene accounts for 0.01 to 2.0% by weight of the conductive paste.

  In this case, the ratio of the holes included in the protruding electrode can be made appropriate. That is, when the polypropylene in the conductive paste is less than 0.01% by weight, the void content in the bump electrode is less than 0.1% by volume, and a crack is formed between the substrate body of the ceramic substrate and the bump electrode. May occur. If the polypropylene in the conductive paste exceeds 2.0% by weight, the void content in the protruding electrode may exceed 20% by volume, and the conductive resistance of the protruding electrode may become extremely large. Therefore, 0.01 to 2.0% by weight of the polypropylene in the conductive paste is preferable.

  Preferably, the metal material accounts for 80 to 98% by weight of the conductive paste.

  In this case, the dimension of the diameter of the hole contained in the protruding electrode can be made appropriate. That is, if the metal material in the conductive paste is less than 80% by weight, the diameter of the pores in the protruding electrode may exceed 10 μmφ, and the conductive resistance of the protruding electrode may become extremely large. When the metal material in the conductive paste exceeds 98% by weight, the diameter of the pores in the protruding electrode becomes less than 0.1 μmφ, and a crack may occur between the substrate body of the ceramic substrate and the protruding electrode. Therefore, the metal material in the conductive paste is preferably 80 to 98% by weight.

  Preferably, in the first step, the protruding electrode patterns provided on the base material of the plurality of constraining layers are connected to each other, and the hole formation in the protruding electrode pattern is formed for each constraining layer. Different material content. The protruding electrode is formed by firing the connected protruding electrode pattern.

  In this case, by changing the ratio of the hole forming material by the constraining layer, the holes of the protruding electrode can be made to have a desired distribution.

  As a preferred embodiment, the content of the hole forming material contained in the pattern for projecting electrode of the plurality of constraining layers in the first step is such that the content of the hole forming material in the projecting electrode is closer to the substrate body. It selects so that the ratio of the said void | hole may increase.

  In this case, the shear stress due to the deflection of the printed circuit board on which the ceramic substrate is mounted can be relaxed on the base end side (substrate body side) of the protruding electrode having a large percentage of holes.

  As another preferable aspect, the content of the hole forming material contained in the pattern for the projecting electrode of the plurality of constraining layers in the first step is such that the projecting electrode on the side opposite to the substrate body. It selects so that the ratio of the said void | hole in the inside may increase.

  In this case, the shear stress due to the deflection of the printed wiring board on which the ceramic substrate is mounted can be relaxed on the tip end side (opposite side of the substrate body) of the protruding electrode having a large percentage of holes.

  Preferably, in the third step, the protruding electrode is disposed along a peripheral edge of the one main surface of the substrate body. The semiconductor device further includes a fourth step of mounting a mounting component in a region surrounded by the protruding electrode on the one main surface of the substrate body.

  In this case, when the ceramic substrate is mounted on the printed wiring board, the mounting component mounted on the ceramic substrate is disposed between the ceramic substrate and the printed wiring board and protected.

  More preferably, the fourth step includes a step of mounting another mounting component on the other main surface of the substrate body.

  In this case, mounting components can be mounted on the ceramic substrate at a higher density.

  Preferably, the unfired ceramic substrate includes a plurality of unfired ceramic layers stacked, and has an unfired interlayer connection electrode pattern and an unfired in-plane electrode pattern inside the unfired ceramic substrate. .

  In this case, the mounting density can be increased by forming an electric circuit inside the substrate body.

  The present invention also provides a ceramic substrate configured as follows.

  The ceramic substrate has a protruding electrode formed on at least one main surface of the ceramic substrate by simultaneous firing with the ceramic substrate and having pores therein.

  According to the above configuration, the protruding electrode can be formed while suppressing shrinkage during firing, and the strength of the protruding electrode can be increased by the voids inside the protruding electrode.

  The protruding electrode is preferably a columnar shape such as a substantially circular column or a substantially rectangular column, but may have a substantially conical shape, a truncated pyramid (approximately a truncated cone or a substantially truncated pyramid), or a substantially hemispherical shape. It is.

  Preferably, the holes occupy 0.1 to 20% by volume of the protruding electrodes.

  In this case, the ratio of the holes included in the protruding electrode can be made appropriate. That is, if the void content in the protruding electrode is less than 0.1% by volume, cracks occur between the substrate body of the ceramic substrate and the protruding electrode, and the void content exceeds 20% by volume. Since the conduction resistance of the protruding electrode may become extremely large, the void content is preferably 0.1 to 20% by volume.

  Preferably, the hole has a diameter of 0.1 to 10 μmφ.

  In this case, the dimension of the diameter of the hole contained in the protruding electrode can be made appropriate. That is, if the hole diameter is less than 0.1 μmφ, a crack occurs between the substrate body of the ceramic substrate and the protruding electrode, and if the hole diameter exceeds 10 μmφ, the conduction resistance of the protruding electrode is extremely large. Therefore, the pore diameter is preferably 0.1 to 10 μmφ.

  According to the present invention, a protruding electrode can be formed while suppressing shrinkage during firing.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  (Example 1) The manufacturing method of a ceramic substrate is demonstrated referring FIGS. 1-5, FIG.

  First, as shown in FIG. 1, ceramic green sheets 11 a to 11 d for the base material layer 10 and ceramic green sheets 21 a to 21 d; 23 a to 23 d for the constraining layers 20 and 22 are prepared.

The ceramic green sheets 11a to 11d for the base material layer 10 are produced using a ceramic material. Specifically, glass powder 50 to 64 wt% of a composition comprising CaO 10 to 55 wt%, SiO ₂ 45 to 70 wt%, Al ₂ O ₃ 0 to ₃₀ wt%, impurities 0 to 10 wt%, and B ₂ O ₃ 5 to 20 wt%. Then, a mixture composed of 35 to 50 wt% of Al ₂ O ₃ powder having impurities of 0 to 10 wt% is dispersed in an organic vehicle including an organic solvent, a plasticizer, and the like to prepare a slurry. Subsequently, the obtained slurry is formed into a sheet shape by a doctor blade method or a casting method to produce a ceramic green sheet of unsintered glass ceramic.

  The base material layer 10 may be composed of only one ceramic green sheet instead of laminating a plurality of ceramic green sheets.

  Moreover, although it is preferable to use the ceramic green sheet | seat of the unsintered glass ceramic formed by the sheet forming method mentioned above for the base material layer 10, the unsintered thick film printed layer formed by the thick film printing method is used. May be.

  In addition to the insulator material described above, the ceramic powder may be a magnetic material such as ferrite, or a dielectric material such as barium titanate. However, the ceramic green sheet for the substrate layer 10 is 1050 ° C. or lower. A low-temperature sintered ceramic green sheet that sinters at a temperature of 5 ° C. is preferable. For this reason, the above-described glass powder preferably has a softening point of 750 ° C. or lower.

  Next, on the ceramic green sheet of unsintered glass ceramic, via patterns 13a to 13d to be interlayer connection electrode patterns, conductor patterns 12a to be surface conductor patterns, and conductor patterns 12b to 12d to be in-plane electrode patterns Form. The via patterns 13a to 13d are formed by, for example, printing a conductive paste obtained by kneading a conductive material powder together with an organic binder or a solvent into a through-hole processed in a green glass ceramic green sheet by punching or laser processing. Embed by For the conductor patterns 12a to 12d, a conductive paste obtained by kneading a conductor material powder with an organic binder or a solvent is printed by, for example, a screen printing method or a gravure printing method, or a metal foil having a predetermined pattern shape is transferred. It is formed by the method of doing. The conductive paste will be described later.

  The conductor pattern on the surface includes a portion where a through conductor such as a via conductor or a through-hole conductor for connecting conductor patterns between upper and lower layers is exposed on the surface.

  The ceramic green sheets 21a to 21d; 23a to 23d for the constraining layers 20 and 22 are made of ceramic powder such as alumina that does not substantially sinter at the firing temperature of the ceramic green sheets 11a to 11d for the base layer 10. By using a binder in an organic vehicle composed of an organic binder, an organic solvent, a plasticizer, etc., preparing a slurry, and forming the resulting slurry into a sheet based on a doctor blade method, a casting method, etc. Make it. The sintering temperature of the ceramic green sheets 21a to 21d; 23a to 23d for the constraining layers 20 and 22 is, for example, 1400 to 1600 ° C., and is substantially equal to the sintering temperature of the unsintered glass ceramic green sheet for the base material layer 10. Does not sinter.

  For the purpose of forming the protruding electrode 18 described later, an unfired protrusion is formed by embedding a conductive paste described later by printing or the like in a through hole formed in the ceramic green sheet for the constraining layer 22 by punching or laser processing. Ceramic green sheets 23a-23c for constraining layer 22 having electrode patterns 25a-25c are formed.

  The constraining layers 20 and 22 may also be composed of only one ceramic green sheet.

  Here, the average particle size of the ceramic powder used for the constraining layers 20 and 22 is preferably 0.1 to 5.0 μm. When the average particle size of the ceramic powder is less than 0.1 μm, it reacts violently during firing with the glass contained in the vicinity of the surface layer of the unsintered glass ceramic sheet, and the ceramic layer and the constraining layer adhere firmly after firing. This makes it difficult to remove the constraining layer, and due to the small particle size, not only the ceramic green sheet for the constraining layer but also the organic components such as the binder in the unsintered glass ceramic green sheet are difficult to decompose and scatter during firing. Delamination may occur inside. On the other hand, if the thickness exceeds 5.0 μm, the suppression of firing shrinkage is reduced, and the substrate tends to shrink or swell in the plane direction more than necessary.

  Moreover, the ceramic powder which comprises the constrained layers 20 and 22 should just be a ceramic powder which does not sinter substantially at the calcination temperature of the ceramic green sheets 11a-11d of the base material layer 10, In addition to an alumina, zirconia, magnesia, etc. The ceramic powder can also be used.

  However, in order to sufficiently apply the restraining force of the constraining layers 20 and 22 to the base material layer 10, the glass near the surface layer is constrained at the boundary where the surface layer of the base material layer 10 and the constraining layers 20 and 22 are in contact with each other. It is necessary to wet the layers 20 and 22 suitably. Therefore, the ceramic powder constituting the constraining layers 20 and 22 is preferably the same type of ceramic powder as the ceramic powder constituting the base layer 10.

  The conductive paste used for the conductor patterns 12a to 12d and the via patterns 13a to 13d of the base material layer 10 and the protruding electrode patterns 25a to 25c of the constraining layer 22 is a low resistance and hardly oxidizable material as a conductor material in the paste. What has Ag as a main component is preferable.

  The conductive paste used for the protruding electrode patterns 25a to 25c of the constraining layer 22 is mainly used as a hole forming material for allowing the holes 18x to exist in the protruding electrodes 18 as shown in FIG. 6B after firing. In addition to the component Ag, resin beads that do not dissolve in the solvent are included. As the resin beads of the pore forming material, at least one kind mainly composed of polypropylene, polyethylene, polystyrene, polyester or the like is added. The resin beads are not limited to a spherical shape, and various shapes such as a flat shape can be used.

  When polypropylene is used for the resin beads, the amount of polypropylene added is preferably 0.01 wt% to 2.0 wt%. In the case of less than 0.01 wt%, the content of the voids 18x is less than 0.1 vol% with respect to the unit volume of the protruding electrode 18 formed by baking the protruding electrode patterns 25a to 25c. The thermal stress applied to the protruding electrode 18 during cooling may not be sufficiently relaxed. Further, when the amount of polypropylene added is more than 2.0 wt%, the content ratio of the holes 18 x with respect to the unit volume of the protruding electrode 18 is more than 20.0 vol%, and the conductive resistance is increased. When energized, the power lost in this part may become extremely large.

  The conductive paste can be produced by adding a predetermined amount of an organic vehicle such as an organic binder and a solvent to the main component powder in a predetermined ratio, and stirring and kneading. However, the order of blending the main component powder, resin beads, organic vehicle and the like is not particularly limited.

  The content of Ag contained in the conductive paste is preferably 80 wt% to 98 wt%.

  When the amount is less than 80 wt%, the amount of Ag filled in the through-hole formed in the ceramic green sheet for the constraining layer 22 is reduced. As a result, a hole 18x larger than 10 μmφ is generated, and the protruding electrode 18 not only has an extremely large conduction resistance, but also weakens against shear stress, and the protruding electrode 18 may be broken at worst.

  On the other hand, if it exceeds 98 wt%, the Ag content in the protruding electrode patterns 25a to 25c of the ceramic green sheets 23a to 23c for the constraining layer 22 increases, so that Ag and the base material (ceramic) of the ceramic green sheet Due to the difference in the amount of shrinkage between the base material layer 10 and the protruding electrode 18 due to the cooling after forming the protruding electrode, a large thermal stress is applied to the protruding electrode 18 due to the difference in thermal expansion. Due to the thermal stress, a large crack is generated between the surface of the base material layer 10 and the protruding electrode 18, and as a result, it is impossible to satisfactorily connect the protruding electrode 18 and the conductor pattern or via of the base material layer 10. It becomes.

  Therefore, the content of Ag contained in the conductive paste is preferably 80 wt% to 98 wt%, and more preferably 85 wt% to 95 wt%.

  In addition, it is desirable that the Ag powder as the main component powder has no coarse powder or extremely agglomerated powder, and that the maximum coarse particle size after forming the conductive paste is 50 μm or less.

  The organic vehicle is a mixture of a binder resin and a solvent. As the binder resin, for example, ethyl cellulose, acrylic resin, polyvinyl butyral, methacrylic resin, or the like can be used.

  As the solvent, for example, terpineol, dihydroterpineol, dihydroterpineol acetate, butyl carbitol, butyl carbitol acetate, alcohols and the like can be used.

  Moreover, you may add various dispersing agents, a plasticizer, an activator, etc. as needed.

  In addition, the viscosity of the conductive paste is preferably 50 to 700 Pa · s in consideration of filling properties and printability.

  As the conductive patterns 12a to 12d and the via patterns 13a to 13d of the base material layer 10, the same conductive paste as that used for the protruding electrode patterns 25a to 25c to which resin beads such as polypropylene are added can be used. However, a resin to which resin beads are not added is usually used.

  Next, as shown in FIG. 2, ceramic green sheets 23 a to 23 d for the constraining layer 22 are superimposed on one main surface of the base material layer 10 having the ceramic green sheets 11 a to 11 d, and protrusions are formed on the other main surface. The ceramic green sheets 21a to 21d for the constraining layer 20 having no electrode pattern are superposed and pressure-bonded under a pressure of 5 to 200 MPa, for example, based on a hydrostatic press. As a result, the composite laminate 14 in which the constraining layers 20 and 22 are adhered to both main surfaces of the base material layer 10 is produced.

  Note that only the ceramic green sheets 23a to 23c for the constraining layer 22 having the protruding electrode patterns 25a to 25c are superimposed on one main surface of the base material layer 10, and the ceramic green for the constraining layer 22 without the protruding electrode pattern is overlapped. The sheet 23d may be omitted. On the contrary, ceramic green sheets 23a-23c for constraining layer 22 having projecting electrode patterns 25a-25c are superposed on one main surface of base material layer 10, and two or more constraining layers without projecting electrode patterns are superimposed. The ceramic green sheets 23d for 22 may be overlapped.

  The thickness of the constraining layers 20 and 22 is preferably 25 to 1000 μm. When the thickness of the constraining layers 20 and 22 is less than 25 μm, the suppression force of firing shrinkage is reduced, and the base material layer 10 may shrink or swell in the plane direction more than necessary, and on the other hand, when the thickness exceeds 1000 μm. In addition, organic components such as binders in the ceramic green sheets 11 a to 11 d of the base material layer 10 are not easily decomposed and scattered during firing, and delamination tends to occur in the base material layer 10.

  Next, as shown in FIG. 3, the composite laminate 14 is fired at a firing temperature of the ceramic green sheets 11 a to 11 d of the base material layer 10, for example, 800 to 1050 ° C. in a known belt furnace or batch furnace. The ceramic green sheets 11a to 11d of the material layer 10 are sintered. As the firing atmosphere, air, nitrogen, hydrogen, water, or the like may be introduced during firing as necessary.

  Next, by removing the base material of the constraining layers 20 and 22 from the fired composite laminate 14, a protruding electrode is formed on one main surface of the fired base material layer 10, that is, the substrate body 16, as shown in FIG. 4. The ceramic substrate 15 provided with the protruding electrodes 18 formed by firing the patterns 25a to 25c is taken out.

  In the composite laminate 14 after firing, the constraining layers 20 and 22 are not substantially sintered except for the protruding electrodes 18, and the organic components contained before firing are scattered and porous. Since it is in a quality state, it can be easily removed by a sand blast method, a wet blast method, an ultrasonic vibration method, or the like.

  Next, as shown in FIG. 5, a passive component 30 such as a multilayer ceramic capacitor is mounted with solder 31 on the surface electrodes 17a and 17b on both main surfaces of the substrate body 16 of the ceramic substrate 15, and an IC 32 having bump electrodes is soldered. The composite ceramic substrate 40 is formed by flip-chip bonding via the ball 33 and wire bonding the IC 34 with the bonding wire 35.

  As shown in FIG. 11, the IC 34 is mounted in a region 19 surrounded by the protruding electrodes 18 formed along the periphery on one main surface of the substrate body 16 of the ceramic substrate 15. The IC 34 may be sealed with resin as necessary. At this time, the surface of the protruding electrode 18 is somewhat deviated due to the disappearance of the resin beads. Therefore, the bonding force with the sealing resin is high, and the omission of the sealing resin is suppressed.

  As shown in FIG. 6A, the composite ceramic substrate 40 is connected to the pad electrode 52 of the printed wiring board 50 by the solder 54 on the tip 18 s side of the protruding electrode 18.

  As schematically shown in the enlarged view of FIG. 6B, pores 18x (pores or pores) are dispersed in the metal sintered body at a predetermined ratio inside the protruding electrode 18. .

  The presence of the holes 18x in the protruding electrode 18 causes a large amount in the protruding electrode 18 due to a difference in contraction amount between the base material of the constraining layers 20 and 22 and the protruding electrode patterns 25a to 25c during cooling after firing. The occurrence of cracks (so-called opening or dents) is suppressed, and as a result, the strength of the protruding electrodes 18, the plating resistance can be improved, and the conduction resistance can be reduced.

  In particular, when the holes 18x are distributed on the base end 18t side (board body 16 side) of the protruding electrode 18, in the structure in which the ceramic board 15 is mounted on the printed wiring board 50, the printed wiring board 50 is subjected to external force. When the bent state is applied, the shear stress generated between the substrate body 16 and the protruding electrode 18 of the ceramic substrate 15 is relieved, and peeling between the substrate body 16 and the protruding electrode 18 is less likely to occur. . The protruding electrode as described above may be provided on the main surface opposite to the main surface on which the protruding electrode 18 is provided.

  (Modification) With reference to FIGS. 7 to 10, a modification in which the ratio of the holes (porosity) included in the protruding electrodes is inclined will be described.

  Prepare a plurality of unfired ceramic green sheets for constraining layers having protruding electrode patterns filled with through-holes of conductive pastes with different mixing amounts of resin beads such as polypropylene, and combine them appropriately to obtain unfired substrates By superposing on one main surface of the layer 10, the vacancies of the protruding electrodes can be made to have a desired distribution.

  For example, as in the protruding electrode 18a shown in FIG. 7, the number of holes 18x is increased on the base end 18t side. In this case, peeling between the substrate body 16 and the protruding electrode 18a is less likely to occur, and mouth opening in the protruding electrode 18a can be suppressed at the interface between the ceramic green sheets 23a and 23b for the constraining layer 22. .

  As in the protruding electrode 18b shown in FIG. 8, the number of holes 18x may increase on the tip 18s side. In this case, the opening in the protruding electrode 18b at the interface between the ceramic green sheets 23b and 23c for the constraining layer 22 can be suppressed.

  Further, the holes 18x may be intermittently distributed as in the protruding electrodes 18c and 18d of FIGS. In this case, a conductive paste containing resin beads and a conductive paste not containing resin beads are alternately used for the protruding electrode pattern of each sheet of the constraining layer.

  In the conductive paste containing resin beads, the conductive paste containing resin beads is increased by increasing the resin bead content, compared to the case where all protruding electrode patterns are formed using the same conductive paste. It is preferable to compensate for the shrinkage during firing of the used pattern for protruding electrodes.

  The conductive paste not containing resin beads can be the same as that used for the conductive patterns 12a to 12d and the via patterns 13a to 13d of the ceramic green sheets 11a to 11d of the base material layer 10. That is, it is desirable to form a large number of pores where the opening is likely to occur in the protruding electrode, in other words, where the stress due to the difference between the firing shrinkage force of the protruding electrode and the constraining force of the constraining layer tends to concentrate.

  (Specific example) Next, the specific example which produced the ceramic substrate is demonstrated.

First, 40 parts by weight of alumina powder and 60 parts by weight of SiO ₂ (60% by weight) -B ₂ O ₃ (8% by weight) -Al ₂ O ₃ (6% by weight) -CaO (26% by weight) glass. A powder (softening point: 700 ° C.) is dispersed in an organic vehicle containing an organic binder made of acrylic, an organic solvent made of toluene and isopropylene alcohol, and a plasticizer made of di-n-butyl phthalate to prepare a slurry. did. Subsequently, this slurry was formed into a sheet by a doctor blade method to produce a ceramic green sheet for an unsintered glass ceramic layer.

  Also, an alumina powder (average particle size: 0.4 μm) that does not substantially sinter at the firing temperature of the ceramic green sheet for an unsintered glass ceramic layer is made of an organic binder made of polyvinyl butyral, toluene, and isopropylene alcohol. A slurry was prepared by dispersing in an organic vehicle containing an organic solvent and a plasticizer comprising di-n-butyl phthalate. Next, the slurry was formed into a sheet by a doctor blade method to produce a ceramic green sheet for constraining layer having a thickness of 100 μm. The sintering temperature of the constraining layer ceramic green sheet is 1600 ° C.

  In addition, as a conductive paste, Ag is used as a main component, and the content in the polypropylene paste is adjusted to the amount shown in Table 1 below, and 1 wt% of ethyl cellulose resin and terpineol are mixed to give a viscosity of about It was produced so as to be 200 Pa · s.

  Next, 200 μmφ vias were formed on the ceramic green sheet for the unsintered glass ceramic layer by punching, and 600 μm × 600 μm vias were formed on the ceramic green sheet for the constraining layer, and the conductive paste was filled by printing.

  Next, four ceramic green sheets for constraining layers with through holes filled in one main surface of the ceramic green sheet for unsintered glass ceramic layer on which the conductor pattern is formed, and ceramic green sheets for constraining layers without through holes 1 Two ceramic green sheets for unsintered glass ceramic layers are laminated by stacking 5 sheets of ceramic green sheets for constraining layers without through-holes on the other main surface and pressing them at a pressure of 100 MPa. A glass ceramic green sheet composite laminate for evaluation of protruding electrodes having a ceramic green sheet for constraining layer on the main surface was prepared.

  Next, the obtained composite laminate was introduced into the atmosphere up to 750 ° C. (oxygen concentration of 10,000 ppm or more), nitrogen was introduced from 750 ° C. to 900 ° C. to 750 ° C., and the oxygen concentration in the range of 850 ° C. to 900 ° C. was 1000 ppm or less. The green glass ceramic layer was sintered as follows. Thereafter, the constraining layer in a porous state was removed from the fired composite laminate by a wet blast method, and the glass ceramic substrate was taken out.

  About the obtained glass-ceramic substrate for protruding electrode evaluation, after polishing the cross section of the said glass-ceramic substrate into a mirror surface, the quantity of the void | hole per unit area of a protruding electrode was measured by SEM. The measurement results are shown in Table 1 below.

  Moreover, about the obtained glass-ceramic board for protruding electrode evaluation, it solder-mounts to a 100 mm x 40 mm x 1.6mm printed circuit board, and the printed circuit board surface from the surface opposite to the mounting surface of this ceramic board is 2 mm / s. The printed circuit board was deformed by applying a load so as to obtain a constant displacement amount, and the displacement amount of the printed circuit board when the protruding electrode evaluation ceramic substrate was broken was determined as the flexural strength. Of the obtained deflection strengths, those less than 2 mm were determined as defective.

  Moreover, about the obtained glass ceramic substrate for protruding electrode evaluation, the conduction resistance of the 0.6 mm × 0.6 mm × 0.5 mm protruding electrode was measured by a two-terminal method. Of the obtained conduction resistance, 1Ω or more was judged as defective.

The above is summarized as shown in Table 1 below.

  From Table 1, in order to obtain a glass ceramic substrate having a deflection strength of 2 mm or more and a conduction resistance of less than 1 Ω, the void content in the protruding electrode is required to be 0.1 to 20.0 vol%, and therefore It is understood that the polypropylene content in the conductive paste is required to be 0.01 to 2.0 wt%.

  On the other hand, when the polypropylene content in the conductive paste is less than 0.01 wt%, the void content in the bump electrode is less than 0.1 vol%, and a large crack is generated between the ceramic surface and the bump electrode. I have. This is because a large thermal stress is applied to the protruding electrode due to the difference in shrinkage between the dielectric and the protruding conductor due to cooling after the protruding electrode is formed, and a large crack is generated between the ceramic surface and the protruding electrode due to the stress. As a result, it becomes impossible to connect the protruding conductor and the via well. Moreover, when the content of polypropylene in the conductive paste was more than 2.0 wt%, the void content in the protruding electrode was more than 20.0 vol%, and the conduction resistance was extremely increased.

  (Summary) As described above, by including resin beads in the conductive paste for forming the protruding electrode, the protruding electrode can be formed while suppressing shrinkage during firing.

  The present invention is not limited to the above-described embodiment, and can be implemented with various modifications.

  For example, a resin other than resin beads may be used as the hole forming material. In addition to the columnar shape such as a substantially columnar shape or a substantially prismatic shape, the protruding electrode may have a shape such as a substantially conical shape, a truncated pyramid shape (approximately a truncated cone shape or a substantially truncated pyramid shape), or a substantially hemispherical shape.

It is explanatory drawing of the manufacturing process of a ceramic substrate. (Example) It is explanatory drawing of the manufacturing process of a ceramic substrate. (Example) It is explanatory drawing of the manufacturing process of a ceramic substrate. (Example) It is explanatory drawing of the manufacturing process of a ceramic substrate. (Example) It is explanatory drawing of a composite ceramic substrate. (Example) It is explanatory drawing of the mounted state of a composite ceramic substrate, (B) It is an expanded sectional view of a protruding electrode. It is an expanded sectional view of a protruding electrode. (Modification 1) It is an expanded sectional view of a protruding electrode. (Modification 2) It is an expanded sectional view of a protruding electrode. (Modification 3) It is an expanded sectional view of a protruding electrode. (Modification 4) It is a perspective view of a ceramic substrate. (Example) It is explanatory drawing of a mouth opening. It is explanatory drawing of a dent.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Base material layer 11a-11d Ceramic green sheet 14 Composite laminated body 15 Ceramic substrate 16 Board | substrate main body 18,18a, 18b, 18c, 18d Protrusion electrode 18s Tip 18t Base end 18x Hole 19 area | region 20 Restriction layer 21a-21d Ceramic green sheet 22 constraining layers 23a to 23d ceramic green sheets 25a to 25c protruding conductors 40 composite ceramic substrate 50 printed wiring board

Claims (16)

One main surface of the unfired ceramic substrate includes a pore forming material and a metal material sintered at the firing temperature of the unfired ceramic substrate in a base material that is not substantially sintered at the firing temperature of the unfired ceramic substrate. A first step of forming an unfired composite laminate formed by adhering a constraining layer having an unfired protruding electrode pattern;
The base material of the constraining layer does not substantially sinter, the void forming material contained in the protruding electrode pattern of the constraining layer disappears, and the unfired ceramic substrate and the unfired of the constraining layer A second step of firing the unfired composite laminate at a temperature at which the metal material contained in the pattern for protruding electrodes can be sintered;
The base material of the constraining layer is removed, and a projecting electrode formed by firing the pattern for the projecting electrode of the constraining layer is provided on one main surface of the substrate body formed by firing the unfired ceramic substrate. A third step of taking out the ceramic substrate,
The method of manufacturing a ceramic substrate, wherein the protruding electrode includes a hole formed of the hole forming material included in the protruding electrode pattern of the constraining layer in the second step.   In the first step, the protruding electrode pattern is formed by filling a through hole provided in the base material of the constraining layer with a conductive paste containing the hole forming material and the metal material. The manufacturing method according to claim 1, wherein:   In the first step, the hole forming material is included in the conductive paste at a ratio in which the voids occupy 0.1 to 20% by volume of the protruding electrode in the third step. The manufacturing method according to claim 2, wherein:   The hole forming material contained in the conductive paste in the first step is selected so that the diameter of the hole is 0.1 to 10 μmφ in the third step. The manufacturing method according to claim 2, wherein the manufacturing method is characterized. The conductive paste includes a binder resin and a solvent,
The manufacturing method according to claim 2, 3, or 4, wherein the pore forming material is resin beads that do not dissolve in the solvent.   The manufacturing method according to claim 5, wherein the resin beads are mainly composed of polypropylene, and the polypropylene accounts for 0.01 to 2.0% by weight of the conductive paste.   The manufacturing method according to claim 2, wherein the metal material accounts for 80 to 98% by weight of the conductive paste. In the first step, the protruding electrode patterns provided on the base material of the plurality of constraining layers are connected to each other, and the void forming material is included in the protruding electrode pattern for each constraining layer. Vary the amount,
The manufacturing method according to claim 1, wherein the protruding electrode is formed by firing the connected pattern for protruding electrodes.   In the first step, the content of the hole forming material included in the protruding electrode patterns of the plurality of constraining layers is such that the ratio of the holes in the protruding electrode is closer to the substrate body. 9. The manufacturing method according to claim 8, wherein the number is selected so as to increase.   In the first step, the content of the hole forming material included in the protruding electrode pattern of the plurality of constraining layers is a ratio of the holes in the protruding electrode on the side opposite to the substrate body. 9. The manufacturing method according to claim 8, wherein the selection is made so that the number of In the third step, the protruding electrode is disposed along a peripheral edge of the one main surface of the substrate body,
11. The method according to claim 1, further comprising a fourth step of mounting a mounting component in a region surrounded by the protruding electrode on the one main surface of the substrate body. Manufacturing method.   The manufacturing method according to claim 11, wherein the fourth step includes a step of mounting another mounting component on the other main surface of the substrate body. The green ceramic substrate includes a plurality of stacked green ceramic layers,
10. The method according to claim 1, further comprising an unfired interlayer connection electrode pattern and an unfired in-plane electrode pattern inside the unfired ceramic substrate.   A ceramic substrate comprising a protruding electrode formed on at least one main surface of the ceramic substrate by simultaneous firing with the ceramic substrate and having pores therein.   The ceramic substrate according to claim 14, wherein the pores occupy 0.1 to 20% by volume of the protruding electrodes.   The ceramic substrate according to claim 14 or 15, wherein a diameter of the holes is 0.1 to 10 µmφ.

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