JP2007123448A - Manufacturing method of ceramic substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a ceramic substrate, which improves the strength of a protruded electrode. <P>SOLUTION: (1) There is formed a non-calcined composite laminate on at least one principal surface of a non-calcined ceramic substrate body, with which a restriction layer is brought into close contact, the restriction layer which includes a non-calcined protruded electrode pattern containing a metal material sintered at a calcination temperature of the ceramic substrate body in a base member not substantially sintered at the calcination temperature of the ceramic substrate body. (2) The non-calcined composite laminate is calcined at a temperature where the ceramic substrate body is sintered without permitting the base member of the restriction layer to be substantially sintered, but where the metal material contained in the protruded electrode pattern of the restriction layer is sintered. (3) The ceramic substrate 15 having a protruded electrode 18 formed by the calcination of the protruded electrode pattern is taken out on the one principal surface of the calcined ceramic substrate body 16 by removing the base member of the restriction layer. In a second process, at least a part of the metal material contained in the protruded electrode pattern is melted. <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 at least 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, 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 this composite laminate, a protruding electrode obtained by sintering a conductive paste filled in a hole of a specific shrinkage-suppressing ceramic green sheet is provided on one main surface of the multilayer ceramic substrate.

  In the multilayer ceramic substrate thus manufactured, the protruding electrode is made of a sintered body, and therefore, the protruding electrode is made of a structure formed by necking of Ag grains. This structure by necking of Ag grains causes necking of Ag grains without completely eliminating the space existing between adjacent Ag grains. Therefore, the interior of the protruding electrode after firing has a space between Ag grains. It will be in the state.

Therefore, the protruding electrode supported by the necking of the Ag grains is under a high pressure of about 0.1 × 10 ⁶ to 10 × 10 ⁶ Pa for removing the shrinkage-suppressing support after firing in the non-shrink process. In the blast cleaning, the necking is cut off and it is easy to break at the protruding electrode. In particular, among the protruding electrodes, the protruding electrode obtained by mixing and sintering shrinkage additive such as alumina in the protruding electrode Ag paste further inhibits the necking of Ag particles, so that the protruding electrode is a non-shrinking process. It becomes easier to break when removing the shrinkage-suppressing support.

  In view of such circumstances, the present invention intends to provide a method for manufacturing a ceramic substrate capable of improving the strength of a protruding electrode.

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

  The method for producing a ceramic substrate includes: (1) the unfired ceramic substrate in at least one main surface of the unfired ceramic substrate body in a base material that is not substantially sintered at the firing temperature of the unfired ceramic substrate body. A first step of forming an unfired composite laminate formed by adhering a constraining layer having an unfired protruding electrode pattern containing a metal material sintered at the firing temperature of the main body, and (2) unfired The ceramic substrate body is sintered, the base material of the constraining layer is not substantially sintered, and the metal material contained in the unfired pattern for protruding electrodes of the constraining layer is sintered. A second step of firing the unfired composite laminate at a sintering temperature; and (3) a substrate formed by firing the unfired ceramic substrate body by removing the base material of the constraining layer. The constraining layer is formed on one main surface of the main body. And a third step of removing a ceramic substrate having protruding electrodes formed by firing of the projecting electrode pattern of the green. In the second step, at least a part of the metal material contained in the protruding electrode pattern of the constraining layer is melted.

  According to the above method, when the metal material in the protruding electrode pattern of the constraining layer forms a eutectic phase during firing in the second step, the additive metal in contact with the main component metal powder, for example, Ag powder, Since the contacting Cu powder has a melting point below the maximum temperature of firing, Ag and Cu dissolve and become a liquid metal during firing. The Ag powder around the liquid metal is necked due to sintering behavior, and the liquid metal comes into contact with the surrounding Ag powder and is suitably wetted. It will be a thing. Therefore, it exhibits physical properties such as thicker necking, higher density, lower porosity, and eutectic phase compared to a normal Ag sintered body, and the bonding of metal particles becomes stronger. Therefore, the protruding electrode is difficult to break when the base material of the constraining layer is removed in the third step.

  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 unfired projecting electrode pattern is formed of a conductive paste containing a plurality of types of the metal materials. The conductive paste includes, as a plurality of types of metal materials, a main component of Ag and a metal other than Ag capable of forming a eutectic with Ag at a temperature equal to or lower than the temperature in the second step (hereinafter referred to as “additional”). "Metal").

  Although the melting point of Ag is about 960 ° C., for example, when 27 parts by weight of Cu is added to 100 parts by weight of Ag, the eutectic point (eutectic temperature) becomes about 780 ° C. That is, by adding an additive metal to the main component Ag and lowering the eutectic temperature of the metal material in the unfired projection electrode pattern to be lower than the firing temperature (about 800 to 1000 ° C.) in the second step, Melting of the protruding electrode can be promoted.

  Preferably, the additive metal is at least one selected from the group consisting of Cu, Al, Be, Bi, Ge, Mg, Si, and Sn.

  These additive metals are materials that can form a eutectic with Ag. Cu is particularly preferable from the viewpoints of availability and ease of adjustment.

  Preferably, the additive metal accounts for 0.1 to 10% by weight of the conductive paste.

  That is, when the additive metal in the conductive paste is less than 0.1% by weight, necking between Ag particles may not be strengthened. When the additive metal in the conductive paste is more than 10% by weight, a large gap is generated in the protruding electrode, and the protruding electrode may be easily broken when the substrate of the constraining layer is removed in the third step. . Therefore, the additive metal in the conductive paste is preferably 0.1 to 10% by weight, more preferably 3 to 8% by weight.

  Preferably, the Ag occupies 80 to 98% by weight of the conductive paste.

  That is, if the Ag in the conductive paste is less than 80% by weight, a large void is generated inside the protruding electrode, and not only the conduction resistance of the protruding electrode is extremely increased, but also it is weak against shear stress, In the worst case, the protruding electrode may break. When the metal material in the conductive paste exceeds 98% by weight, it is easily affected by the difference in thermal expansion between Ag and ceramic, and a crack may occur between the substrate body and the protruding electrode. Therefore, the metal material in the conductive paste is preferably 80 to 98% by weight, more preferably 85 to 95% by weight.

  Preferably, the conductive paste contains substantially only materials other than glass powder and ceramic powder.

  In general, the strength can be improved by adding glass powder or ceramic powder. However, in the case of the present invention, when such inorganic powder is contained, the inorganic powder serves as a base material for the constraining layer. It may react with the constituent material (for example, ceramic powder) and cause undesired deformation of the protruding electrode. It also causes a decrease in the conductivity of the protruding electrode (increase in specific resistance). Therefore, it is preferable that the conductive paste forming the protruding electrode does not substantially contain glass powder and ceramic powder.

  Preferably, in the first step, a plurality of the constraining layers are laminated to connect the unfired protruding electrode patterns provided on the base material of the constraining layer, and for each constraining layer The content of the metal material in the conductive paste for forming the unfired bump electrode pattern is varied. In the second step, at least a part of the metal material included in the protruding electrode pattern of at least one of the constraining layers among the connected protruding electrode patterns is melted. In the third step, the protruding electrode is formed by firing the protruding electrode pattern connected in the first step.

  The constraining layer projecting electrode pattern connected in the first step is best when the metal material in the projecting electrode pattern is in a molten state in all constraining layers during firing in the second step. If the metal material in the protruding electrode pattern is melted in at least one constraining layer, the strength of the protruding electrode can be improved. By making the content of the metal material in the pattern for the projecting electrode different for each constraining layer, the projecting electrode can be formed to have a gradient composition and a desired strength distribution.

  Preferably, in the second step, at least a part of the metal material contained in the pattern for the protruding electrode of at least one of the constraining layers on the side close to the ceramic substrate body is melted.

  In this case, since the metal material melts and sinters at least on the side close to the ceramic substrate main body, the strength of the base end side (substrate main body side) that is most likely to break in the bump electrode can be improved.

  Preferably, in the third step, the protruding electrode is disposed along a peripheral edge of at least one main surface of the substrate body. The method for manufacturing a ceramic substrate further includes (4) a fourth step of mounting a mounting component in a region surrounded by the protruding electrodes 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 board main body is disposed and protected between the board main body and the printed wiring board.

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

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

  Preferably, the unfired ceramic substrate body includes a plurality of laminated unfired ceramic layers, and an unfired interlayer connection electrode pattern and unfired in-plane electrodes are formed inside the unfired ceramic substrate body. It has a pattern for use.

  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 substrate body by simultaneous firing with the substrate body. At least a part of the protruding electrode melts during the simultaneous firing.

  According to the above configuration, since the protruding electrode is in a molten state at the time of firing, the necking is thicker, the density is higher, the porosity is lower, and the eutectic is larger than when sintered without being melted. It exhibits physical properties such as exhibiting a phase, and the bonding of metal particles becomes stronger. Therefore, the protruding electrode is difficult to break when removing the base material of the constraining layer in close contact with the substrate body.

  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 protruding electrode contains Ag as a main component and further contains an additive metal other than Ag. The additive metal can form a eutectic with the Ag at a temperature equal to or lower than the temperature at the time of the co-firing.

  Although the melting point of Ag is about 960 ° C., for example, when 27 parts by weight of Cu is added to 100 parts by weight of Ag, the eutectic point (eutectic temperature) becomes about 780 ° C. That is, an additive metal is added to the main component Ag, and the eutectic temperature of the metal material for forming the protruding electrode is made lower than the temperature at the time of co-firing (about 800 to 1000 ° C.). Melting can proceed.

  Preferably, the additive metal is at least one selected from the group consisting of Cu, Al, Be, Bi, Ge, Mg, Si, and Sn.

  These additive metals are materials that can form a eutectic with Ag. Cu is particularly preferable from the viewpoints of availability and ease of adjustment.

  Preferably, the protruding electrode substantially contains only a material other than glass powder and ceramic powder.

  In general, the strength can be improved by adding glass powder or ceramic powder. However, in the case of the present invention, when such inorganic powder is contained, the inorganic powder is baked into the substrate body. It may react with the material (for example, ceramic powder) which comprises the base material of the constraining layer closely_contact | adhered to a board | substrate body in order to constrain a deformation | transformation, and may cause an unwanted deformation | transformation to a protruding electrode. It also causes a decrease in the conductivity of the protruding electrode (increase in specific resistance). Therefore, it is preferable that the protruding electrode does not substantially contain glass powder and ceramic powder.

  Preferably, the protruding electrode is formed by connecting a plurality of layers having different melting states during the simultaneous firing.

  According to the above configuration, the protruding electrode has a gradient composition and can have a desired intensity distribution.

  Preferably, at least a part of at least one of the layers on the side of the protruding electrode close to the ceramic substrate body is melted during the simultaneous firing.

  In this case, since at least a part of the protruding electrode is melted at least on the side close to the ceramic substrate body, it is possible to improve the strength of the base end side (ceramic substrate body side) that is most likely to be broken in the protruding electrode.

  According to the present invention, the strength of the protruding electrode can be improved.

  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.

  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, a glass having 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%. A mixture of 50 to 64% by weight of powder and 36 to 50% by weight of Al ₂ O ₃ powder having impurities of 0 to 10% by weight is dispersed in an organic vehicle made of 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 pressure film printed layer formed by the pressure 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 glass powder described above has a softening point of 750 ° C. or lower.

  Next, via patterns 13a to 13d serving as interlayer connection electrode patterns, conductor patterns 12a serving as surface conductor patterns, and conductor patterns 12b to 12d serving as in-plane electrode patterns are formed on the ceramic glass ceramic green sheet. . In the via patterns 13a to 13d, a conductive paste obtained by pasting a conductive material powder into a through-hole processed in a ceramic glass ceramic green sheet by punching, laser processing or the like is embedded by printing, for example. The conductive patterns 12a to 12d are formed by printing a conductive paste obtained by pasting a conductive material powder by, for example, a screen printing method or a gravure printing method, or by transferring a metal foil having a predetermined pattern shape.

  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.

  As a conductive material in the conductive paste, a material mainly composed of Ag which is a low resistance and hardly oxidizable material is preferable.

  Moreover, in order to obtain the projection electrodes 18 (see FIGS. 4 to 7) in which at least a part is melted in the projection electrode patterns 25a to 25c of the ceramic green sheets 23a to 23c of the constraining layer 22 described later, In addition to Ag, a bump electrode paste to which at least one additive such as Cu, Al, Be, Bi, Ge, Mg, Si, Sn is added is used.

  When using Cu for an additive, the addition amount of Cu is preferably 0.1% by weight to 10% by weight. If it is less than 0.1% by weight, the melted portion in the protruding electrode becomes extremely small at the time of firing, and it becomes impossible to obtain a strong necking between Ag particles, so that the protruding electrode breaks during blast cleaning under high pressure. It is easy to end.

  On the other hand, if it exceeds 10% by weight, the number of melted portions in the bump electrode during firing becomes extremely large, and the space that existed between the Ag grains becomes extremely small. In the worst case, adjacent protruding electrodes come into contact with each other, and electrical insulation cannot be maintained. Alternatively, a large gap is generated inside the protruding electrode, and the protruding electrode is likely to be broken during blast cleaning under high pressure.

  The conductive paste can be produced by adding a predetermined amount of an organic vehicle at a predetermined ratio to the above main component powder, stirring and kneading. However, the order of blending the main component powder, additive component powder, organic vehicle and the like is not particularly limited.

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

  When the amount is less than 80% by weight, the amount of filling into the through holes formed in the ceramic green sheets 23a to 23c for the constraining layer 22 is reduced, so that a large void is generated inside the protruding electrode due to the constraining force of the constraining layer 22. As a result, not only the conduction resistance of the protruding electrode becomes extremely large but also weak against the shear stress, and the protruding electrode is broken at worst.

  On the other hand, if it exceeds 98% by weight, the amount of filling in the through holes of the ceramic green sheets 23a to 23c for the constraining layer 22 increases, so that it is easily affected by the difference in thermal expansion between Ag and ceramic. Due to the difference in shrinkage between the base material layer 10 and the protruding electrode 18 due to cooling, a large thermal stress is applied to the protruding electrode 18, and the surface of the base material layer 10 and the protruding electrode 18 are caused by this thermal stress. As a result, a large crack is generated between the protruding electrode 18 and the conductive pattern or via of the base material layer 10.

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

  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.

  The viscosity of the conductive paste is preferably 50 to 700 Pa · s in consideration of printability.

  In addition, conductive paste different from the bump electrode paste, that is, an additive such as Cu is added to the via patterns 13a to 13d and the conductor patterns 12a to 12 of the ceramic green sheets 11a to 11d of the base material layer 10. A paste that is not used may be used.

  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 a protruding electrode, for the unfired protruding electrode by means such as embedding the protruding electrode paste in a through hole formed in the ceramic green sheet for the constraining layer 22 by punching, laser processing or the like. Ceramic green sheets 23a to 23c for the constraining layer 22 having patterns 25a to 25c are formed.

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

  Here, the average particle diameter 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 vigorously during firing with the glass contained in the vicinity of the surface layer of the unsintered glass ceramic layer (base material layer 10), and the ceramic layer after firing There are cases where the constraining layer is in close contact and the constraining layer cannot be removed, or due to the small particle size, organic components such as a binder in the sheet are hardly decomposed and scattered during firing, and delamination may occur in the substrate. On the other hand, when the thickness exceeds 5.0 μm, the suppression force of firing shrinkage becomes small, 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 for a large amount of glass to be present in the surface layer region of the base material layer 10, it is necessary that the glass on the surface layer be suitably wet with respect to the constraining layers 20 and 22 at the boundary where the surface layer and the constraining layers 20 and 22 are in contact with each other. 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 substrate layer 10.

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 × 10 ^{6 to} 20 × 10 ⁶ Pa, 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.

  The constraining layers 20 and 22 preferably have a thickness of 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.

  Further, ceramic green sheets 23a to 23c for the constraining layer 22 having protruding electrode patterns 25a to 25c are superposed on one main surface of the base material layer 10, and further, the constraining layer 22 having no two or more protruding electrode patterns. Ceramic green sheets 23d for use may be overlaid. On the other hand, 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 for the constraining layer 22 having no protruding electrode pattern is overlapped. The green sheet 23d may be eliminated.

  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 substrate other than the base material of the constraining layers 20 and 22, that is, the protruding electrodes 18, is not substantially sintered, and the organic components contained before firing are scattered. However, since it is in a porous state, it can be easily removed by a sand blast method, a wet blast method, an ultrasonic vibration method, or the like.

At this time, since the protruding electrodes 18 are tightly necked between the Ag particles, the restraint by the sand blasting method, the wet blasting method, the ultrasonic vibration method or the like under a high pressure of about 0.1 × 10 ⁶ to 10 × 10 ⁶ Pa. Even when the layers 20 and 22 are removed, the constraining layers 20 and 22 can be satisfactorily removed without breaking the protruding electrode 18.

  In the protruding electrode 18, it is not necessary that all Ag grains are melted. In this case, the protruding electrode includes a sintered Ag region and a molten Ag region. Further, it is preferable that a part of all the protruding electrodes arranged on the periphery is melted. However, only one of the plurality of protruding electrodes may be in a molten state. Absent. In addition, the protruding electrodes may be formed on both surfaces of the ceramic substrate.

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

  As shown in FIG. 7, 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 ceramic substrate body 16 of the ceramic substrate 15.

  For example, as shown in FIG. 6, 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.

  (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. Subsequently, this slurry was formed into a sheet by a doctor blade method to produce a ceramic green sheet for an auxiliary layer having a thickness of 100 μm. The sintering temperature of the auxiliary layer ceramic green sheet is 1600 ° C.

  In addition, as a conductive paste, the content of Cu, Al, Be, Bi, Ge, Mg, Si, Sn in the paste with Ag as a main component is adjusted to an amount as shown in Table 1 below. 1% by weight of ethyl cellulose resin and terpineol were mixed to produce a viscosity of about 200 Pa · s.

  Next, via holes of 200 μmφ were formed by punching in the ceramic green sheet for the unsintered glass ceramic layer, and through holes of 600 μm × 600 μm were formed in the ceramic green sheet for the auxiliary layer, and the conductive paste was filled by printing. The number of vias and through holes was 1000.

  Next, the ceramic green sheet for the auxiliary layer with the filled through hole is superimposed on one main surface of the ceramic green sheet for the unsintered glass ceramic layer on which the conductor pattern is formed, and no through hole is formed on the other main surface. The protruding electrode evaluation glass having the auxiliary layer ceramic green sheets on both main surfaces of the ceramic green sheet for the unsintered glass ceramic layer by overlapping the ceramic green sheets for the auxiliary layer and press-bonding them at a pressure of 100 Pa. A ceramic green sheet composite laminate was prepared.

Next, the resulting 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 auxiliary layer in the porous state was removed from the fired composite laminate by wet blasting at a pressure of 10 × 10 ⁶ Pa, and the glass ceramic substrate was taken out.

  The shape of the protruding electrode was observed with a stereomicroscope at a magnification of 10 to 50 times for the glass ceramic substrate, and the number of broken 1000 pieces was measured.

The above is summarized as shown in Table 1 below.

  From Table 1, in order to obtain a ceramic substrate in which the number of folds of protruding electrodes is less than 5 out of 1000, all additives should be in the range of 0.1 to 15.0% by weight. It turns out that is necessary.

  On the other hand, when the content of the additive in the conductive paste was less than 0.1% by weight, 5 or more protruding electrodes were broken during 1000 blast cleaning. This is because most of the sintered body is formed in the formation of the protruding electrode, and thus necking between Ag grains is weakened.

  In addition, when the content of the additive in the conductive paste is more than 10.0% by weight, a large gap of 50 μmφ or more is generated in the protruding electrode, and as a result, the protruding electrode is easily broken during blast cleaning. Oops.

  (Summary) As described above, the protruding electrode 18 can be improved in strength by at least partially melting during firing.

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

  For example, the protruding electrode is preferably in the shape of a column such as a substantially cylinder or a substantially prism, but can also have a substantially conical shape, a truncated pyramid (approximately a truncated cone or a truncated pyramid), or a substantially hemispherical shape. It is. Further, the protruding electrodes may be provided on both main surfaces of the ceramic substrate body.

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 mounting state of a composite ceramic substrate. It is a perspective view of a ceramic substrate. (Example)

Explanation of symbols

10 substrate layer 11a to 11d ceramic green sheet (unfired ceramic layer)
DESCRIPTION OF SYMBOLS 14 Composite laminated body 15 Ceramic substrate 16 Board | substrate body 18,18a, 18b, 18c, 18d Protrusion electrode 18s Tip 18x Hole 19 area | region 20 Constrained layer 21a-21d Ceramic green sheet 22 Constrained layer 23a-23d Ceramic green sheet 25a-25c Protrusion Conductor 40 Composite ceramic board 50 Printed wiring board

Claims (17)

Metal sintered at the firing temperature of the unfired ceramic substrate body in a base material that does not substantially sinter at the firing temperature of the unfired ceramic substrate body on at least one main surface of the unfired ceramic substrate body A first step of forming an unfired composite laminate formed by adhering a constraining layer having an unfired protruding electrode pattern containing a material;
The unfired ceramic substrate body is sintered, the base material of the constraining layer is not substantially sintered, and the metal material contained in the unfired pattern for protruding electrodes of the constraining layer A second step of firing the unfired composite laminate at a temperature at which sintering is performed;
The substrate of the constraining layer is removed and formed on one main surface of the substrate body formed by firing the unfired ceramic substrate body by firing the unfired pattern for protruding electrodes of the constraining layer. A third step of removing the ceramic substrate having the protruding electrode,
In the second step, at least a part of the metal material contained in the protruding electrode pattern of the constraining layer is melted. The unfired pattern for protruding electrodes is formed by a conductive paste containing a plurality of types of the metal materials,
The conductive paste includes, as a plurality of types of metal materials, a main component of Ag and a metal other than Ag capable of forming a eutectic with Ag at a temperature equal to or lower than the temperature in the second step (hereinafter referred to as “additional”). 2. The method for producing a ceramic substrate according to claim 1, wherein the ceramic substrate contains metal.   The method for manufacturing a ceramic substrate according to claim 2, wherein the additive metal is at least one selected from the group consisting of Cu, Al, Be, Bi, Ge, Mg, Si, and Sn.   4. The method of manufacturing a ceramic substrate according to claim 2, wherein the additive metal occupies 0.1 to 10% by weight of the conductive paste. 5.   5. The method of manufacturing a ceramic substrate according to claim 2, wherein the Ag occupies 80 to 98 wt% of the conductive paste.   6. The method of manufacturing a ceramic substrate according to claim 2, wherein the conductive paste substantially contains only a material other than glass powder and ceramic powder. In the first step, a plurality of the constraining layers are stacked, the unfired protruding electrode patterns provided on the base material of the constraining layer are connected, and unfired for each constraining layer. Different content of the metal material in the conductive paste forming the pattern for the protruding electrode,
In the second step, among the connected projecting electrode patterns, at least a part of the metal material included in the projecting electrode pattern of at least one constraining layer is melted,
7. The projecting electrode according to claim 1, wherein, in the third step, the projecting electrode is formed by firing the projecting electrode pattern connected in the first step. 8. Ceramic substrate manufacturing method.   In the second step, at least a part of the metal material contained in the protruding electrode pattern of at least one of the constraining layers on the side close to the ceramic substrate body is melted. Item 8. A method for producing a ceramic substrate according to Item 7. In the third step, the protruding electrode is disposed along a peripheral edge of at least one main surface of the substrate body,
9. 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. Ceramic substrate manufacturing method.   The method of manufacturing a ceramic substrate according to claim 9, wherein the fourth step includes a step of mounting another mounting component on the other main surface of the substrate body.   The unfired ceramic substrate body includes a plurality of laminated unfired ceramic layers, and the unfired ceramic substrate body includes unfired interlayer connection electrode patterns and unfired in-plane electrode patterns. The method for manufacturing a ceramic substrate according to claim 1, wherein the method is provided. At least one main surface of the substrate body has a protruding electrode formed by simultaneous firing with the substrate body,
The protruding electrode is a ceramic substrate, wherein at least a part of the protruding electrode melts during the simultaneous firing. The protruding electrode contains Ag as a main component, and further contains an additive metal other than Ag.
The ceramic substrate according to claim 12, wherein the additive metal can form a eutectic with the Ag at a temperature equal to or lower than the temperature at the time of the co-firing.   The ceramic substrate according to claim 13, wherein the additive metal is at least one selected from the group consisting of Cu, Al, Be, Bi, Ge, Mg, Si, and Sn.   15. The ceramic substrate according to claim 12, 13, or 14, wherein the protruding electrode substantially includes only a material other than glass powder and ceramic powder.   The ceramic substrate according to any one of claims 12 to 15, wherein the protruding electrode is formed by connecting a plurality of layers having different melting states during the simultaneous firing.   The ceramic substrate according to claim 16, wherein at least one of the layers on the side of the protruding electrode close to the substrate body is melted at the time of the simultaneous firing.

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