JP4735018B2 - Multilayer ceramic substrate and manufacturing method thereof - Google Patents

Description

  The present invention relates to a multilayer ceramic substrate and a manufacturing method thereof, and more particularly to a multilayer ceramic substrate including a through conductor provided so as to penetrate a specific ceramic layer in a thickness direction and a manufacturing method thereof.

The multilayer ceramic substrate has a three-dimensional wiring conductor composed of a film-like in-plane conductor extending along the main surface of the ceramic layer and a through conductor (via hole conductor) penetrating the ceramic layer in the thickness direction. Is formed. The through conductor is provided with a through hole in the ceramic green sheet by, for example, irradiation of CO ₂ laser light or punching, and then the through hole is filled with a conductive paste in which conductive powder is dispersed in an organic vehicle. It is formed by going through each step.

  However, the process for providing the through-hole and the process for filling the through-hole with the conductive paste are very difficult and time-consuming, and therefore require a high cost.

For example, when a CO ₂ laser is used to provide a through hole for a through conductor, in addition to the device itself being expensive, the irradiated portion is scattered when the ceramic green sheet is irradiated with laser light, The scattered matter may adhere to the peripheral wall of the through hole, and the through hole having a desired shape may not be formed.

  On the other hand, when punching is used to provide the through-holes, it is difficult to form many through-holes, particularly small-diameter through-holes at a time, because the punching is mechanical.

  Furthermore, the through conductors are miniaturized as the density of the multilayer ceramic substrate increases. Therefore, as the through hole for the through conductor is miniaturized and the miniaturization of the through hole proceeds, the filling process of the conductive paste into the through hole becomes more difficult, resulting in poor filling. It is easy to cause disconnection at the through conductor.

  In view of such a situation, several methods for manufacturing a multilayer ceramic substrate having a three-dimensional wiring conductor are proposed without going through a through hole forming step for providing a through conductor and a conductive paste filling step. Has been.

  For example, in Japanese Patent Application Laid-Open No. 2003-347731 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2001-135548 (Patent Document 2), a protruding conductor (bump portion or conductor protrusion) is formed on a first ceramic green sheet. It is described that a through conductor is formed by piercing the second ceramic green sheet to form a three-dimensional wiring conductor inside the multilayer ceramic substrate.

However, according to the above method, depending on the hardness of each of the first and second ceramic green sheets and the protruding conductor, the protruding conductor may not pierce the second ceramic green sheet. In some cases, poor conduction is caused between the in-plane conductor provided on the second ceramic green sheet and the through conductor provided by the protruding conductor.
JP 2003-347731 A JP 2001-135548 A

  Therefore, the object of the present invention can stably form a through conductor with high connection reliability without going through the through hole forming step and the conductive paste filling step, while solving the above-described problems. An object is to provide a method for manufacturing a multilayer ceramic substrate.

  Another object of the present invention is to provide a multilayer ceramic substrate structure that can be manufactured by the manufacturing method as described above.

In order to solve the above-described technical problem, the method for manufacturing a multilayer ceramic substrate according to the present invention substantially includes a firing temperature for sintering the first ceramic green sheet on the first ceramic green sheet. Forming a first constraining layer containing an inorganic material powder that is not sintered, and forming a first projecting conductor so that at least a part of the first constraining layer is located on the first constraining layer. A first embedding step of embedding the first protruding conductor together with the first constraining layer in the first ceramic green sheet, and stacking a plurality of ceramic green sheets including the first ceramic green sheet, In addition, a green sheet laminate is produced by pressing a plurality of ceramic green sheets in the laminating direction. To formed, it is mainly characterized in that it comprises a firing step.
In the first embodiment, in the first embedding step, a part of the first constraining layer is in a state of scooping up along at least a part of the peripheral side surface of the first protruding conductor. Yes.

The first embodiment further includes a step of forming a first in-plane conductor using a conductive paste obtained by dispersing conductive powder in an organic vehicle, and the first protruding conductor described above is provided. In the forming step, the first protruding conductor is formed so that at least a part of the first in-plane conductor is placed on the portion located on the first constraining layer. In the first embedding step described above, The first projecting conductor is preferably embedded in the first ceramic green sheet together with each of the first constraining layer and the first in-plane conductor.
In the above case, in the first embedding step, at least a part of the end surface at the front end in the embedding direction of the first protruding conductor is covered with both the first constraining layer and the first in-plane conductor. A step of forming a second in-plane conductor on the second ceramic green sheet using a conductive paste, and the laminating step includes the first projecting conductor and the second in-plane A step of laminating the first ceramic green sheet and the second ceramic green sheet so that the conductor is in contact, and the firing step includes sintering the first protruding conductor and the second in-plane conductor by sintering; It is more preferable to provide the process to join.

In the first embodiment , the first embedding step is preferably performed so as to press the entire first ceramic green sheet in the thickness direction together with the first protruding conductor.

In the above case , a step of forming a second constraining layer containing inorganic material powder on the second ceramic green sheet, a step of forming a second protruding conductor on the second constraining layer, The entire second ceramic green sheet is pressed in the thickness direction together with the two projecting conductors, so that the second projecting conductor is bonded to the second ceramic green sheet together with a part of the second constraining layer. And a second embedding step embedded therein, and the laminating step includes a step of stacking the first and second ceramic green sheets and pressing in the laminating direction after the first and second embedding steps. It may be .

In the second embodiment, in the method of manufacturing a multilayer ceramic substrate according to the present invention, in addition to the main features described above, the first embedding step includes the first projecting conductor and the entire first ceramic green sheet. Forming a second constraining layer containing an inorganic material powder on the second ceramic green sheet, and a second projecting conductor on the second constraining layer. And the step of laminating the first ceramic green sheet after the first embedding step with the second projecting conductor formed side facing the first ceramic green sheet. The second ceramic green sheets are stacked on top of each other, and the first and second ceramic green sheets are pressed in the stacking direction so that the second protruding conductors are part of the second constraining layer. Both embedded within the second ceramic green sheet, and further comprising a second embedding step.
In the second embodiment described above, the method further includes the step of forming the second in-plane conductor using a conductive paste so that at least a part of the second in-plane conductor is placed on the second constraining layer, The conductor is formed so that at least a part of the conductor rides on the second in-plane conductor, and the second embedding step is configured to connect the second projecting conductor to the second constraining layer and the second in-plane conductor. It is preferable to implement so as to be embedded in the second ceramic green sheet together with each part.

  In the present invention, preferably, the protruding conductor is formed using a conductive paste in which conductive powder is dispersed in an organic vehicle.

  In the present invention, the constraining layer is preferably formed over the entire surface of the ceramic green sheet.

  The present invention is also directed to a multilayer ceramic substrate having the following structural features.

That is, in the first embodiment , the multilayer ceramic substrate according to the present invention includes a plurality of laminated ceramic layers, an in-plane conductor provided so as to extend along the main surface of the specific ceramic layer, and a specific A through conductor provided so as to penetrate the ceramic layer in the thickness direction, and at least a portion of the material of the ceramic layer from the constraining layer penetrates between the ceramic layer and the in-plane conductor. The intervening layer containing the inorganic material powder adhered thereto is formed, and each of the intervening layer and each of the in-plane conductors crawls along at least a part of the peripheral side surface of the through conductor.
In the second embodiment, the multilayer ceramic substrate according to the present invention is connected to the plurality of laminated ceramic layers, a through conductor provided so as to penetrate the specific ceramic layer in the thickness direction, and the through conductor. First and second in-plane conductors provided to extend along the main surface of the specific ceramic layer and the main surface of the ceramic layer adjacent to the ceramic layer, and at least the ceramic layer and the first surface An intervening layer including an inorganic material powder in which a part of the material of the ceramic layer permeates and is fixed is formed between the inner conductor and the inner conductor. Each part of the in-plane conductor of 1 is scooped up, and at least a part of one end face of the through conductor is not covered by any of the intervening layer and the first in-plane conductor, and the second face Inner conductor is penetrating It is characterized by being bonded directly when.

  In the multilayer ceramic substrate according to the present invention, the in-plane conductor that crawls up along the peripheral side surface of the through conductor is a surface formed along the main surface of the ceramic layer adjacent to the ceramic layer forming the in-plane conductor. It is preferable to be electrically connected directly to the inner conductor.

  The multilayer ceramic substrate according to the present invention may further include a surface mount component mounted on the surface.

  According to the method for manufacturing a multilayer ceramic substrate according to the present invention, in order to provide the through conductor that penetrates the ceramic layer in the thickness direction, the protruding conductor is embedded in the ceramic green sheet itself on which the protruding conductor is formed. As a result, neither the process of forming a through hole in the ceramic green sheet nor the process of filling the through hole with a conductive paste is required. Therefore, not only can the number of steps to be performed to manufacture a multilayer ceramic substrate be reduced, but also the steps with high difficulty can be eliminated, and as a result, defects that are likely to occur in the steps with high difficulty. , And productivity can be improved, and a highly reliable multilayer ceramic substrate can be manufactured.

  Further, according to the method for manufacturing a multilayer ceramic substrate according to the present invention, a constraining layer containing an inorganic material powder that does not substantially sinter at a firing temperature for sintering the ceramic green sheet is formed on the ceramic green sheet. However, since the protruding conductor is formed so that at least a part of the protruding conductor is placed on the portion located on the constraining layer, when the protruding conductor is embedded in the ceramic green sheet, the constraining layer also accompanies it. Is called.

  Therefore, first, it is possible to obtain a state in which a part of the constraining layer crawls up along at least a part of the peripheral side surface of the protruding conductor embedded in the ceramic green sheet. According to this state, since the shrinkage of the constraining layer does not substantially occur in the firing step, the constraining layer acts so as to suppress the shrinkage in the stacking direction of the protruding conductors, and in the stacking direction of the protruding conductors. The dimensions can be maintained well. As a result, when an in-plane conductor is formed in relation to the protruding conductor, the reliability of the electrical connection between the in-plane conductor and another adjacent in-plane conductor in the stacking direction is improved. Can be increased. In particular, when the protruding conductor is formed using a conductive paste in which conductive powder is dispersed in an organic vehicle, the problem of shrinkage in the firing process is unavoidable, so the above-mentioned effect is more prominent. Demonstrated.

  In the method for manufacturing a multilayer ceramic substrate according to the present invention, when the protruding conductor is formed so that at least a part is placed on the portion located on the constraining layer of the in-plane conductor, it is embedded in the ceramic green sheet. It is possible to obtain a state in which a part of the in-plane conductor crawls up along at least part of the peripheral side surface of the protruding conductor. According to this state, the bonding reliability between the through conductor formed by the protruding conductor and the in-plane conductor is high, and therefore the reliability of electrical connection can be further increased.

According to the second embodiment of the method for manufacturing a multilayer ceramic substrate according to the present invention, when the protruding conductor is embedded in the ceramic green sheet, the entire ceramic green sheet is pressed in the thickness direction together with the protruding conductor. Therefore , the plurality of protruding conductors can be embedded at a time, and the density of the ceramic green sheets can be increased and made harder than that before pressing. Therefore, after the first embedding step, the second ceramic green sheet is stacked on the first ceramic green sheet with the side on which the second protruding conductor is formed facing the first ceramic green sheet, In addition, the first and second ceramic green sheets are pressed in the laminating direction, thereby enabling the second embedding process to be performed, in which the second protruding conductors are embedded in the second ceramic green sheet.

  Further, in the method for manufacturing a multilayer ceramic substrate according to the present invention, when the constraining layer is formed over the entire surface of the ceramic green sheet, the constraining layer can contribute to the improvement of the dimensional accuracy of the obtained multilayer ceramic substrate. .

  According to the multilayer ceramic substrate according to the present invention, since each part of the intervening layer and the in-plane conductor crawls along at least a part of the peripheral side surface of the through conductor, the shape of the through conductor is well maintained. In addition, a highly reliable electrical connection state can be obtained between the through conductor and the in-plane conductor.

  In the multilayer ceramic substrate according to the present invention, the in-plane conductor that crawls along the peripheral side surface of the through conductor is formed along the main surface of the ceramic layer adjacent to the ceramic layer that forms the in-plane conductor. If the two in-plane conductors are electrically connected directly, a highly reliable electrical connection state can be obtained even between these two in-plane conductors.

  1 to 3 are for explaining a first embodiment of the present invention. Here, FIG. 1 is a cross-sectional view showing the multilayer ceramic substrate 1, and FIG. 2 is an enlarged cross-sectional view showing a part of the multilayer ceramic substrate 1 shown in FIG.

  As shown in FIG. 1, a multilayer ceramic substrate 1 includes a plurality of laminated ceramic layers 2, and a plurality of in-plane conductors 3 provided so as to extend in a film shape along the main surface of the specific ceramic layer 2. And a plurality of through conductors 4 provided so as to penetrate the specific ceramic layer 2 in the thickness direction.

  The multilayer ceramic substrate 1 is also provided with several external electrodes 5 on its external surface. The multilayer ceramic substrate 1 includes several surface mount components 6 and 7 mounted on the surface thereof. The surface mount component 6 is electrically connected to a specific outer surface electrode 5 by solder 8, and the surface mount component 7 is electrically connected to a specific outer surface electrode 5 by solder 9.

  In such a multilayer ceramic substrate 1, an intervening layer 18 is formed at least between the ceramic layer 2 and the in-plane conductor 3. In this embodiment, the intervening layer 18 is formed over the entire surface of each ceramic layer 2. The intervening layer 18 includes an inorganic material powder that does not substantially sinter in the firing step for obtaining the sintered ceramic layer 2, and the inorganic powder penetrates part of the material of the ceramic layer 2. It is fixed.

  In the multilayer ceramic substrate 1, each part of the intervening layer 18 and the in-plane conductor 3 is in a state of rising along at least a part of the peripheral side surface 10 of the through conductor 4.

  In FIG. 1, no intervening layer is present on the peripheral side surface 10 of the through conductor 4 in the lowermost ceramic layer 2, but each of the intervening layer and the in-plane conductor is also present on the peripheral side surface 10 of the through conductor 4. The part may crawl up. In particular, in a multilayer ceramic substrate, the connection strength between the in-plane conductor or through conductor provided in the ceramic layer on the surface and the ceramic layer may be a problem, so the lowermost ceramic layer, and further the uppermost ceramic layer. Then, it is preferable that each part of the intervening layer and the in-plane conductor is in a state where it crawls up to at least a part, preferably all of the peripheral side surface of the through conductor.

  2, specific ones of the ceramic layer 2, the in-plane conductor 3, the through conductor 4, and the intervening layer 18 shown in FIG. 1 are shown. Here, when it is necessary to distinguish each of the four ceramic layers 2, the three in-plane conductors 3, the two through conductors 4, and the three intervening layers 18 shown in FIG. Are denoted by reference numerals 2 (a), 2 (b), 2 (c) and 2 (d), and for the in-plane conductor 3, 3 (a), 3 (b) and 3 (c) Reference numerals are attached, the through conductors 4 are assigned reference numerals 4 (a) and 4 (b), and the intervening layer 18 is referenced 18 (a), 18 (b) and 18 (c). A sign is attached.

  Referring to FIG. 2, for example, the in-plane conductor 3 (a) that crawls up along the peripheral side surface 10 of the through conductor 4 (a) is the ceramic layer 2 that forms the in-plane conductor 3 (a). It is electrically connected directly to the in-plane conductor 3 (b) formed along the main surface of the ceramic layer 2 (c) adjacent to b). Similarly, the in-plane conductor 3 (b) rising along the peripheral side surface 10 of the through conductor 4 (b) is adjacent to the ceramic layer 2 (c) forming the in-plane conductor 3 (b). An in-plane conductor 3 (c) formed along the main surface of the matching ceramic layer 2 (d) is electrically connected directly.

  The multilayer ceramic substrate 1 having the above configuration can be manufactured as follows. FIG. 3 is a cross-sectional view for explaining a method of manufacturing the multilayer ceramic substrate 1, and is particularly carried out for manufacturing a portion including the ceramic layers 2 (b) and 2 (c) shown in FIG. 2. The steps are sequentially shown. Therefore, in order to manufacture the multilayer ceramic substrate 1, the process shown in FIG. 3 is repeated until the ceramic layers 2 have a desired number of layers.

  As shown in FIG. 3A, a first ceramic green sheet 11 is prepared. The first ceramic green sheet 11 should be the ceramic layer 2 (b) shown in FIG. The plurality of ceramic green sheets including the first ceramic green sheet 11 prepared for manufacturing the multilayer ceramic substrate 1 are preferably composed of a glass ceramic material, that is, a low-temperature sintered ceramic material. It may contain a sintered ceramic material.

  The ceramic green sheet containing the low-temperature sintered ceramic material is mixed with, for example, powders of barium oxide, silicon oxide, alumina, calcium oxide and boron oxide, and as a binder, polyvinyl butyral as a binder and a plasticizer. A slurry prepared by further mixing di-n-butyl phthalate and a solvent composed of toluene and isopropylene alcohol is formed into a sheet shape on a carrier film by a doctor blade method or the like. In FIG. 3A, the first ceramic green sheet 11 is backed by the carrier film 12 used at the time of molding described above.

  Next, as shown in FIG. 3A, the first constraining layer 19 is formed on the first ceramic green sheet 11. The plurality of constraining layers including the first constraining layer 19 formed for manufacturing the multilayer ceramic substrate is substantially at a firing temperature for sintering the plurality of ceramic green sheets including the first ceramic green sheet 11. Inorganic powder, such as alumina, is not included.

  The constraining layer is formed by applying a paste prepared by mixing an inorganic material powder and an organic vehicle onto a ceramic green sheet by screen printing or the like. In this embodiment, the constraining layer is formed over the entire surface of the ceramic green sheet.

  Next, as shown in FIG. 3 (1), the first in-plane conductor 13 is formed using a conductive paste so that at least a part is on the first constraining layer 19. In this embodiment, all the portions of the first in-plane conductor 13 are formed on the first constraining layer 19.

  The plurality of in-plane conductors including the first in-plane conductor 13 are formed by a known printing method such as a screen printing method. The conductive paste used to form a plurality of in-plane conductors including the first in-plane conductor 13 is obtained by dispersing conductive powder in an organic vehicle.

  Here, as the conductive powder, for example, a powder made of Cu, Ni, Au, Ag, Ag-Pd, Ag-Pt or the like can be used. As the binder contained in the organic vehicle, for example, ethyl cellulose, acrylic Resin, polyvinyl butyral, and the like can be used. As the solvent contained in the organic vehicle, for example, terpineol, butyl carbitol, butyl carbitol acetate, alcohols, and the like can be used.

  Moreover, the content rate of the electroconductive powder in an electroconductive paste is chosen as 50 to 80 weight%, and the particle size of an electroconductive powder is chosen as about 0.1-10 micrometers.

  Next, as shown in FIG. 3 (1), the first projecting conductor 14 is placed so that at least a part of the first in-plane conductor 13 is placed on a portion located on the first constraining layer 19. Is formed. The positional relationship between the first in-plane conductor 13 and the first protruding conductor 14 is determined according to the design of the multilayer ceramic substrate 1 to be obtained. All the portions of the protruding conductor 14 are formed so as to ride on the first in-plane conductor 13.

  The plurality of protruding conductors including the first protruding conductors 14 are preferably made of the same conductive paste as the conductive paste for forming the above-mentioned in-plane conductors in order to avoid complicated process management. . However, when the protruding conductor is formed by printing, it needs to have a predetermined thickness or more, and must be in a state where it can flow by pressurization in a process described later. In consideration of these points, the conductive paste for the protruding conductor preferably has a conductive powder content of 75 to 95% by weight and a particle size of about 0.5 to 30 μm.

  The protruding conductor is preferably formed by printing using a metal mask in order to obtain a predetermined thickness or more. Further, in order to form the protruding conductor thicker, a method of repeating printing a plurality of times may be employed. The protruding conductor may be formed of a metal piece or a metal sintered body having a predetermined shape.

  Next, as shown in FIG. 3 (2), the first ceramic green sheet 11 is held by the upper press die 15 through the carrier film 12 in an inverted state, and the first protruding conductor 14 is The state is directed to the lower press die 16 side.

Next, as shown in FIG. 3 (3), the upper press die 15 and the lower press die 16 are driven so as to be close to each other, and the entire first ceramic green sheet 11 is moved together with the first protruding conductors 14. , Pressed in the thickness direction. In this way, the first embedding process of embedding the first protruding conductor 14 in the first ceramic green sheet 11 is performed. In this first embedding step, as shown in FIG. 3 (3), a part of the first constraining layer 19 and a part of the first in-plane conductor 13 are associated with the first protruding conductor 14. The first constraining layer 19 and the first in-plane conductor 13 are at least partially embedded in the first ceramic green sheet 11 and at least part of the end surface at the front end in the embedding direction of the first protruding conductor 14. It is set as the state which is not coat | covered by any. At this time, if the press die, particularly the upper press die 15 is heated to about 40 to 100 ° C., the ceramic green sheet 11, particularly the surface vicinity of the ceramic green sheet 11 on the upper press die 15 side, becomes soft and has a protruding shape. It becomes easy to embed the conductor 14.

  Next, the upper press die 15 is separated from the first ceramic green sheet 11. At this time, the carrier film 12 lining the first ceramic green sheet 11 is removed from the first ceramic green sheet 11.

  Next, as shown in the upper half of FIG. 3 (4), the second ceramic green sheet 21 is prepared in a state of being lined with a carrier film 22. The second ceramic green sheet 21 should be the ceramic layer 2 (c) shown in FIG.

  A second constraining layer 29 containing an inorganic material powder is formed on the second ceramic green sheet 21, and then a conductive paste is used so that at least a part of the second constraining layer 29 is placed on the second constraining layer 29. The second in-plane conductor 23 is formed, and then the second projecting conductor 24 is placed such that at least a part of the second in-plane conductor 23 rides on a portion of the second in-plane conductor 23 located on the second constraining layer 29. Is formed. In this embodiment, all of the second protruding conductors 24 are formed on the second in-plane conductor 23, and all of the second in-plane conductors 23 are formed on the second constraining layer 29. .

  The second ceramic green sheet 21 is held by the upper press die 15 via the carrier film 22. At this time, the second ceramic green sheet 21 has the side on which the second protruding conductors 24 are formed facing the first ceramic green sheet 11.

  Next, as shown in FIG. 3 (5), the upper press die 15 and the lower press die 16 are close to each other while the second ceramic green sheet 21 is stacked on the first ceramic green sheet 11. So that the first and second ceramic green sheets 11 and 21 are pressed in the laminating direction. As a result of this pressing step, the second embedding step of embedding the second protruding conductor 24 in the second ceramic green sheet 21 is completed.

  That is, among the first and second ceramic green sheets 11 and 21 pressed against each other, the first ceramic green sheet 11 has already been pressed in the step of FIG. The second ceramic green sheet 21 is in a relatively soft state before pressing, whereas the second ceramic green sheet 21 is in a relatively hard state. 2 embedded in the ceramic green sheet 21. At this time, part of each of the second constraining layer 29 and the second in-plane conductor 23 is embedded in the second ceramic green sheet 21 along with the second protruding conductor 24. It is.

  When the lamination process shown in FIG. 3 (5) is completed, the density of the second ceramic green sheet 21 is also increased and is relatively hard as in the case of the first ceramic green sheet 11. ing.

In the structure shown in FIG. 3 (5), the first and second projecting conductors 14 and 24 penetrate the first and second ceramic green sheets 11 and 21 in the thickness direction, respectively. . The first in-plane conductor 13 realizes a state in contact with the second in-plane conductor 23. In addition, the end face at the front end of the first projecting conductor 14 in the embedding direction is in contact with the second in-plane conductor 23.

  In this way, a portion including the ceramic layers 2 (b) and 2 (c) shown in FIG. 2 is manufactured. And in order to obtain the green sheet laminated body for the multilayer ceramic substrate 1, the process demonstrated with reference to FIG. 3 (4) and (5) is repeated until a ceramic green sheet becomes the desired number of lamination | stacking.

  Since the first ceramic green sheet 11 is to be the ceramic layer 2 (b) shown in FIG. 2 as described above, the first ceramic green sheet 11 should be positioned at an intermediate portion in the stacking direction. Therefore, in practice, in the process shown in FIG. 3B, several ceramic green sheets that have already been subjected to the pressing process are arranged on the lower press die 16 in a stacked state.

  The green sheet laminate thus obtained is then fired. In this firing step, when the conductive component contained in the in-plane conductors 13 and 23 and the protruding conductors 14 and 24 contains Ag, for example, when a temperature of about 850 ° C. is applied in the air and Cu is contained, For example, a temperature around 950 ° C. is applied in nitrogen.

When the firing step described above is finished, the green sheet laminate is sintered, and the multilayer ceramic substrate 1 is obtained. Here, the first protruding conductor 14 and the second in-plane conductor 23 shown in FIG. 3 (5) are joined by sintering. In this multilayer ceramic substrate 1, the ceramic layers 2 (b) and 2 (c) shown in FIG. 2 are derived from the first and second ceramic green sheets 11 and 21 shown in FIG. The conductors 3 (a) and 3 (b) are derived from the first and second in-plane conductors 13 and 23, respectively, and the through conductors 4 (a) and 4 (b) are respectively the first and second conductors. The intervening layers 18 (a) and 18 (b) are derived from the first and second constraining layers 19 and 29, respectively.

  In the above-described firing step, the constraining layers 19 and 29 are not substantially contracted. Therefore, the constraining layers 19 and 29 act so as to suppress the contraction of the projecting conductors 14 and 24 in the stacking direction. The dimensions in the stacking direction of 14 and 24 are well maintained. As a result, as shown in FIG. 2, for example, electrical connection by the through conductor 4 (a) between the in-plane conductor 3 (a) and the in-plane conductor 3 (b) adjacent thereto in the stacking direction is performed. Reliability can be increased.

  In addition, as described above, the constraining layers 19 and 29 include an inorganic material powder that is not substantially sintered in the firing step. Therefore, in the intervening layer 18 after firing, the inorganic powder is the material of the ceramic layer 2. It is in a state of being fixed by some penetration.

  As described above, after finishing the firing step, the outer electrode 5 is formed by applying and baking the conductive paste, and the surface mount components 6 and 7 are mounted, and the multilayer ceramic substrate 1 shown in FIG. 1 is completed. . Note that the conductive paste for forming the outer electrode 5 is applied at the stage of the green sheet laminate, and at the same time, the conductive paste for the outer electrode 5 is baked in the firing of the green sheet laminate. It may be.

  In addition, when the green sheet laminate is in a mother state where a plurality of multilayer ceramic substrates 1 can be taken out, a groove for a break line is formed in the green sheet laminate before the firing step. After the surface-mounted components 6 and 7 are mounted, a dividing step along the break line is performed. And the process for attaching a metal cover (not shown) to the multilayer ceramic substrate 1 is implemented as needed.

  FIG. 4 is a view corresponding to FIG. 3 for explaining the second embodiment of the present invention. 4, elements corresponding to those shown in FIG. 3 are denoted by the same reference numerals, and redundant description is omitted.

  In short, in the second embodiment, the steps shown in FIGS. 3 (1) to (3) are performed in advance for each of a plurality of ceramic green sheets to be laminated at a stage before lamination. It is characterized by that.

  In the lower half of FIG. 4 (1), the first ceramic green sheet 11 after the process shown in FIG. 3 (3) is illustrated. On the other hand, the second ceramic green sheet 21 is shown in the upper half of FIG. 4 (1). The second ceramic green sheet 21 is also shown in FIGS. 3 (1) to 3 (3). The process has been completed.

  Therefore, in the first ceramic green sheet 11, the first protruding conductor 14 is embedded in the inside together with a part of the first constraining layer 19 and a part of the first in-plane conductor 13. In the second ceramic green sheet 21, the second projecting conductor 24 is placed inside the second constraining layer 29 and a part of the second in-plane conductor 23. It is in an embedded state.

  Next, as shown in FIG. 4B, the second ceramic green sheet 21 is stacked on the first ceramic green sheet 11, and in this state, the upper press die 15 and the lower press die 16 are mutually connected. By being driven close to each other, the first and second ceramic green sheets 11 and 21 are pressed in the stacking direction.

  The same process is performed on other ceramic green sheets, and a green sheet laminate for the multilayer ceramic substrate 1 is obtained. As for the pressing process, even when each of the plurality of ceramic green sheets including the first and second ceramic green sheets 11 and 21 is stacked, pressing is performed after all the ceramic green sheets are stacked. Alternatively, the pressing may be performed again after all the ceramic green sheets are stacked, while pressing each time the ceramic green sheets are stacked.

  FIG. 5 is a view corresponding to FIG. 3 for explaining a third embodiment of the present invention. In FIG. 5, elements corresponding to those shown in FIG. 3 are denoted by the same reference numerals, and redundant description is omitted.

  In short, the third embodiment is characterized in that the constraining layer is formed only in a region where the protruding conductor on the ceramic green sheet is to be formed.

  FIG. 5 (1) shows a process corresponding to the process shown in FIG. 3 (2). The first constraining layer 19 is not formed over the entire surface of the first ceramic green sheet 11, but is formed only in a region where the first protruding conductor 14 is to be formed.

  FIG. 5B shows a process corresponding to the process shown in FIG. When the upper press die 15 and the lower press die 16 are driven so as to be close to each other and the entire first ceramic green sheet 11 is pressed together with the first protruding conductors 14 in the thickness direction, Like the part of the first in-plane conductor 13, the constraining layer 19 is embedded in the first ceramic green sheet 11 along with the first projecting conductor 14, and the periphery of the first projecting conductor 14. It will be in the state extended along a side.

  Other points are substantially the same as in the case of the first embodiment.

  According to the third embodiment, the effect of improving the dimensional accuracy of the multilayer ceramic substrate by the constraining layer in the firing process cannot be expected so much. However, in order to maintain the shape of the through conductor derived from the protruding conductor, a partial constraining layer is sufficient as in this embodiment.

  In addition, when trying to improve the dimensional accuracy of the multilayer ceramic substrate described above, the following embodiment may be adopted.

  That is, a relatively high sintering temperature such as alumina that does not substantially sinter at the firing temperature in the firing step is disposed on at least one of the upper and lower principal surfaces of the green sheet laminate before firing to be a multilayer ceramic substrate. A green sheet for shrinkage suppression containing a high inorganic material powder is stacked, thereby producing a composite laminate comprising a green sheet laminate and a green sheet for shrinkage suppression. And a baking process is implemented with respect to a composite laminated body. The fired green sheet for shrinkage suppression is removed from the multilayer ceramic substrate.

  In the above-described firing step, the shrinkage-suppressing green sheet is not substantially sintered and therefore hardly shrinks, and acts to suppress shrinkage in the main surface direction with respect to the green sheet laminate in contact therewith. As a result, the dimensional accuracy of the obtained multilayer ceramic substrate 1 can be increased.

  Note that firing the green sheet laminate in a state in which the above-described shrinkage-suppressing green sheets are stacked can be applied to, for example, the first and second embodiments described above.

  FIG. 6 is an enlarged cross-sectional view showing a part of the multilayer ceramic substrate 41 for explaining a fourth embodiment of the present invention. FIG. 6 shows in-plane conductors 45 and 46 and an intervening layer 49 formed along the main surfaces of the first to third ceramic layers 42 to 44 and the second and third ceramic layers 43 and 44, respectively. And a through conductor 47 provided so as to penetrate the second ceramic layer 43 in the thickness direction.

  In the fourth embodiment, a part of the in-plane conductor 45 and a part of the intervening layer 49 crawl up along the peripheral side surface 48 of the penetrating conductor 47. Yes, the other in-plane conductor 46 is not reached. Such a structure is likely to occur when the viscosity of the conductive paste for forming the in-plane conductor 48 and / or the viscosity of the paste containing the inorganic material powder for forming the intervening layer 49 is relatively high.

  FIG. 7 is an enlarged cross-sectional view showing a part of the multilayer ceramic substrate 51 for explaining the fifth embodiment of the present invention. FIG. 7 shows first to third ceramic layers 52 to 54, in-plane conductors 55 and 56 formed along the main surfaces of the second and third ceramic layers 53 and 54, and an intervening layer 60, respectively. 1 and 61, and a through conductor 57 provided so as to penetrate the second ceramic layer 53 in the thickness direction are illustrated.

  In the fifth embodiment, a part of the in-plane conductor 55 is not only crawled up along the peripheral side surface 58 of the through conductor 57 but also on the upper surface 59 of the through conductor 57. It is formed to extend to the inner conductor 56. Such a structure is likely to occur when the viscosity of the conductive paste for forming the in-plane conductor 55 is relatively low.

  Further, in the fifth embodiment, the in-plane conductor 55 does not crawl over the entire circumference of the peripheral side surface 58 of the through conductor 57 but crawls only in a part of the circumferential direction. This is a result of the design for the in-plane conductor 55 and the through conductor 57, so that when the ceramic layer 53 is at the stage of the ceramic green sheet, only part of the in-plane conductor 55 is placed on the in-plane conductor 55. This is because a protruding conductor to be the through conductor 57 is formed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a multilayer ceramic substrate 1 for explaining a first embodiment of the present invention. It is sectional drawing which expands and shows a part of the multilayer ceramic substrate 1 shown in FIG. FIG. 3 is a cross-sectional view sequentially showing steps performed for manufacturing the multilayer ceramic substrate 1 shown in FIG. 1, particularly a portion including the ceramic layers 2 (b) and 2 (c) shown in FIG. 2. It is a figure corresponding to FIG. 3 for demonstrating 2nd Embodiment of this invention. It is a figure corresponding to FIG. 3 for demonstrating the 3rd Embodiment of this invention. FIG. 9 is an enlarged cross-sectional view illustrating a part of a multilayer ceramic substrate 41 for explaining a fourth embodiment of the present invention. FIG. 9 is an enlarged cross-sectional view illustrating a part of a multilayer ceramic substrate 51 for explaining a fifth embodiment of the present invention.

Explanation of symbols

1, 41, 51 Multilayer ceramic substrate 2, 42-44, 52-54 Ceramic layer 3, 13, 23, 45, 46, 55, 56 In-plane conductor 4, 47, 57 Through-conductor 6, 7, Surface mount component 10, 48, 58 Peripheral side surfaces 11, 21 Ceramic green sheets 14, 24 Protruding conductor 15 Upper press die 16 Lower press die 18, 49, 50, 60, 61 Intervening layer 19, 29 Constraining layer

Claims (13)

Forming on the first ceramic green sheet a first constraining layer containing an inorganic material powder that is not substantially sintered at a firing temperature for sintering the first ceramic green sheet;
Forming a first protruding conductor such that at least a portion is on a portion located on the first constraining layer;
The first projecting conductor is embedded in the first ceramic green sheet together with the first constraining layer, and a part of the first constraining layer is a peripheral side surface of the first projecting conductor. A first embedding step that crawls up along at least a portion of
Stacking a plurality of ceramic green sheets including the first ceramic green sheets, and pressing the plurality of ceramic green sheets in a stacking direction to produce a green sheet laminate, a stacking step,
The manufacturing method of a multilayer ceramic substrate provided with the baking process of baking the said green sheet laminated body. A step of forming a first in-plane conductor using a conductive paste in which conductive powder is dispersed in an organic vehicle so that at least a part of the first constrained layer is placed on the first constraining layer;
The step of forming the first projecting conductor includes placing the first projecting conductor so that at least a part of the first projecting conductor rides on a portion of the first in-plane conductor located on the first constraining layer. Comprising the step of forming,
The first embedding step includes a step of embedding the first projecting conductor in the first ceramic green sheet together with each of the first constraining layer and the first in-plane conductor. The manufacturing method of the multilayer ceramic substrate of Claim 1 provided. In the first embedding step, at least a part of the end face at the front end of the first projecting conductor in the embedding direction is covered with either the first constraining layer or the first in-plane conductor. It is not in the state
Using the conductive paste, further comprising the step of forming a second in-plane conductor on the second ceramic green sheet;
The laminating step includes a step of laminating the first ceramic green sheet and the second ceramic green sheet so that the first projecting conductor and the second in-plane conductor are in contact with each other,
The firing step includes a step of joining the first protruding conductor and the second in-plane conductor by sintering.
The manufacturing method of the multilayer ceramic substrate of Claim 2.   3. The method of manufacturing a multilayer ceramic substrate according to claim 1, wherein the first embedding step includes a step of pressing the entire first ceramic green sheet in the thickness direction together with the first protruding conductor. . Forming a second constraining layer containing the inorganic material powder on a second ceramic green sheet;
Forming a second protruding conductor on the second constraining layer;
Along with the second protruding conductor, the entire second ceramic green sheet is pressed in the thickness direction thereof, whereby the second protruding conductor is moved together with a part of the second constraining layer. A second embedding step of embedding in the ceramic green sheet of 2,
The stacking step includes a step of stacking the first and second ceramic green sheets after the first and second embedding steps and pressing in the stacking direction.
The manufacturing method of the multilayer ceramic substrate of Claim 4 . Forming on the first ceramic green sheet a first constraining layer containing an inorganic material powder that is not substantially sintered at a firing temperature for sintering the first ceramic green sheet;
Forming a first protruding conductor such that at least a portion is on a portion located on the first constraining layer;
A first embedding step of embedding the first protruding conductor together with the first constraining layer in the first ceramic green sheet;
Stacking a plurality of ceramic green sheets including the first ceramic green sheets, and pressing the plurality of ceramic green sheets in a stacking direction to produce a green sheet laminate, a stacking step,
Firing the green sheet laminate, and firing step;
With
The first embedding step includes a step of pressing the entire first ceramic green sheet in the thickness direction together with the first protruding conductor,
Forming a second constraining layer containing the inorganic material powder on a second ceramic green sheet;
Forming a second protruding conductor on the second constraining layer;
Further comprising
In the stacking step, after the first embedding step, the side on which the second protruding conductor is formed is directed to the first ceramic green sheet, and the first ceramic green sheet is placed on the first ceramic green sheet. Two ceramic green sheets and pressing the first and second ceramic green sheets in the laminating direction, whereby the second projecting conductors together with a part of the second constraining layer, Including a second embedding step of embedding in the second ceramic green sheet;
A method for producing a multilayer ceramic substrate. The method further includes forming a second in-plane conductor using the conductive paste so that at least part of the second constrained layer is on the second constraining layer. And the second embedding step is configured so that each of the second constraining layer and each of the second in-plane conductors is formed on the second in-plane conductor. The method for producing a multilayer ceramic substrate according to claim 6 , wherein the method is performed so as to be embedded in the second ceramic green sheet together with a part. It said projecting conductors are conductive powder dispersed in an organic vehicle is formed by using a conductive paste comprising, a method for manufacturing a multilayer ceramic substrate according to any one of claims 1 to 7. The constraining layer, the are formed on the entire surface of the ceramic green sheet, a method for manufacturing a multilayer ceramic substrate according to any one of claims 1 to 8. A plurality of laminated ceramic layers, an in-plane conductor provided so as to extend along a main surface of the specific ceramic layer, and a through conductor provided so as to penetrate the specific ceramic layer in the thickness direction; A multilayer ceramic substrate comprising:
At least between the ceramic layer and the in-plane conductor is formed an intervening layer containing an inorganic material powder in which a part of the material of the ceramic layer penetrates and is fixed,
A multilayer ceramic substrate, wherein each of the intervening layer and each of the in-plane conductors crawls up along at least a part of a peripheral side surface of the through conductor. A plurality of laminated ceramic layers, a through conductor provided so as to penetrate the specific ceramic layer in the thickness direction, and connected to the through conductor, adjacent to the main surface of the specific ceramic layer and the ceramic layer A multilayer ceramic substrate comprising first and second in-plane conductors provided to extend along the major surfaces of the mating ceramic layers,
Between at least the ceramic layer and the first in-plane conductor, an intervening layer containing an inorganic material powder to which a part of the material of the ceramic layer has permeated and fixed is formed,
Along each at least part of the peripheral side surface of the through conductor, each part of the intervening layer and the first in-plane conductor crawls up
At least a part of one end face of the through conductor is not covered with either the intervening layer or the first in-plane conductor,
The multilayer ceramic substrate, wherein the second in-plane conductor is directly joined to the through conductor. The in-plane conductor rising up along the peripheral side surface of the through conductor is electrically connected to the in-plane conductor formed along the main surface of the ceramic layer adjacent to the ceramic layer forming the in-plane conductor. The multilayer ceramic substrate according to claim 10 or 11 , which is directly connected. The multilayer ceramic substrate according to claim 10, further comprising a surface mounting component mounted on the surface.

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