JP4957117B2 - Method for producing multilayer ceramic substrate and composite green sheet for producing multilayer ceramic substrate - Google Patents

Description

  The present invention relates to a method for producing a multilayer ceramic substrate and a composite green sheet for producing a multilayer ceramic substrate, and more particularly to a method for producing a multilayer ceramic substrate using a so-called non-shrinkage process, and to produce a multilayer ceramic substrate. The present invention relates to a composite green sheet for producing a multilayer ceramic substrate.

  As a method for manufacturing a multilayer ceramic substrate that is of interest to the present invention, there is one described in Japanese Patent Laid-Open No. 2003-273513 (Patent Document 1). Patent Document 1 describes a method of manufacturing a multilayer ceramic substrate with a cavity by applying a so-called shrinkless process. More specifically, an unfired laminate is prepared in a raw state to be a multi-layer ceramic substrate with a cavity having a structure in which a plurality of unfired ceramic base layers including a low-temperature sintered ceramic powder are laminated. The laminated body is sandwiched between outer constraining layers containing a hardly sinterable ceramic powder, and the unfired laminated body is fired while exerting a shrinkage suppressing action from the outer constraining layer.

  In this case, since the shrinkage suppressing action by the outer constraining layer is weakened, a relatively high degree of shrinkage occurs at a position away from the opening end of the cavity, and the cavity may be deformed undesirably. In the present invention, an interlayer constrained layer containing a hardly sinterable ceramic powder is formed at the interface between a plurality of unfired ceramic substrate layers, thereby trying to suppress undesired deformation at the bank of the cavity.

  After the firing step, the outer constraining layer can be easily removed because the hardly sinterable ceramic powder contained therein is not sintered. On the other hand, the hardly sinterable ceramic powder contained in the interlayer constrained layer is fixed to each other when the glass contained in the base material layer penetrates in the firing step, and as a result, the interlayer constrained layer is densified, Integrated with the layer.

  For this reason, the thickness of the interlayer constrained layer must be such that it can be solidified by the penetration of the glass contained in the substrate layer. In patent document 1, the thickness of about 1-2 micrometers is disclosed as a preferable thickness of an interlayer constrained layer.

  Therefore, the unfired ceramic green sheet that serves as an interlayer constraining layer is very thin and is difficult to handle in the process for producing the unfired laminate to be a multilayer ceramic substrate. In the punching process for forming the film, there is a problem that defects such as tearing and chipping tend to occur. Similar cracks and chipping may occur in the process of providing a through hole for the interlayer connection conductor. As described above, when the above-described defects occur in the ceramic green sheet for the interlayer constraining layer, the shrinkage suppressing effect by the interlayer constraining layer is weakened, and thus the resulting multilayer ceramic substrate is deformed, cracked, disconnected, etc. Causes it to be easier.

In addition, each of the base material layer, the interlayer constrained layer, and the outer constrained layer, which are provided in the green laminate to be fired, each include an organic binder, and prior to the firing step, the organic binder A binder removal process is performed to remove. In this binder removal step, when the amount of the organic binder to be removed is large, the removal of the organic binder does not proceed smoothly, and a non-negligible amount of carbon may remain. In particular, as described above, when an outer constraining layer is provided to produce a multilayer ceramic substrate with cavities, the amount of organic binder to be removed in the debinding process increases. As a result, in the firing step after the binder removal step, there may be a problem that delamination occurs at the interface between the base material layer and the interlayer constraining layer due to residual carbon. Delamination reduces the reliability of the resulting multilayer ceramic substrate.
JP 2003-273513 A

  Accordingly, an object of the present invention is to provide a method for manufacturing a multilayer ceramic substrate that can solve the above-described problems.

  Another object of the present invention is to provide a composite green sheet for producing a multilayer ceramic substrate, which is used for producing the multilayer ceramic substrate described above.

The present invention is positioned such that a plurality of laminated unfired ceramic substrate layers including a low-temperature sintered ceramic powder and a first organic binder and at least one main surface thereof is in contact with the unfired ceramic substrate layer. And a step of producing an unfired composite laminate comprising an unfired ceramic constraining layer comprising a non-sinterable ceramic powder and a second organic binder, and for removing the first and second binders, A binder removal step for removing the binder from the fired composite laminate, and then sintering the low-temperature sintered ceramic powder in the unfired ceramic base layer into the unfired composite laminate, sinterable ceramic powder is sintered at a temperature not substantially sintered, and a firing step, in the step of producing the green composite laminate, the green ceramic substrate The unfired ceramic constraining layer has a thickness of 20 to 200 μm, and the unfired ceramic constraining layer has a thickness of 1 to 10 μm. The firing step penetrates the unfired ceramic constraining layer with the glass component generated in the unfired ceramic base layer. In order to solve the technical problem described above, the present invention is directed to a method for manufacturing a multilayer ceramic substrate comprising a step of densifying the green ceramic constraining layer. An acrylic resin is used as the first organic binder, and a butyral resin is used as the second organic binder in the unfired ceramic constraining layer.

  The present invention is particularly advantageously applied to a method of manufacturing a multilayer ceramic substrate with a cavity. In this case, the unfired composite laminate has a cavity structure composed of a flat plate portion and a bank portion, but it is preferable that an unfired ceramic constraining layer is provided at least on the bank portion.

  As described above, the present invention is advantageously applied to a method for manufacturing a multilayer ceramic substrate using an outer constraining layer. That is, before the binder removal step, a step of providing a non-sintered ceramic outer constraining layer containing a non-sinterable ceramic powder and an organic binder on at least one main surface of the unfired composite laminate is performed, and after the firing step A step of removing the unfired ceramic outer constraining layer is performed.

  In the present invention, the low-temperature sintered ceramic powder preferably includes a ceramic powder and a glass powder.

  In addition, in the step of producing the unfired composite laminate, a step of forming a conductor pattern mainly composed of gold, silver, or copper is performed in relation to the unfired ceramic base layer and / or the unfired ceramic constraining layer. It is preferred that

  In addition, after the firing step, a step of mounting the surface mount electronic component may be further performed on at least one main surface of the composite laminate obtained by firing the unfired composite laminate.

  The present invention is also directed to a composite green sheet for producing a multilayer ceramic substrate, which is used for producing a multilayer ceramic substrate as described above.

The composite green sheet for producing a multilayer ceramic substrate according to the present invention has a form held by a carrier film, and includes a low-temperature sintered ceramic powder and a first organic binder and has an unfired thickness of 20 to 200 μm. A non-fired ceramic having a thickness of 1 to 10 μm , including a ceramic base material layer, at least one main surface thereof being in contact with the non-fired ceramic base material layer, and comprising a non-sinterable ceramic powder and a second organic binder In the firing step for obtaining a multilayer ceramic substrate, the glass component produced in the unfired ceramic base layer is infiltrated into the unfired ceramic restraint layer, thereby forming the unfired ceramic restraint layer. To be densified. An acrylic resin is used as the first organic binder in the unfired ceramic base layer, and a butyral resin is used as the second organic binder in the unfired ceramic constraining layer.

  In this invention, two types of organic materials are used, such as using an acrylic resin as the first organic binder in the unfired ceramic substrate and using a butyral resin as the second organic binder in the unfired ceramic constraining layer. Different binders are used. Comparing the removal behavior of acrylic resin and butyral resin in each binder removal process, acrylic resin belongs to the category of thermal decomposition binder resin, and is a reaction that is mainly vaporized by polymer decomposition due to heat. That is, it is removed by a thermal decomposition reaction. On the other hand, butyral resins belong to the category of combustion binder resins, and are removed by a reaction in which carbon in the resin is combined with oxygen to generate carbon dioxide or carbon monoxide, that is, a combustion reaction.

  Therefore, in general, the acrylic resin is more excellent in degreasing properties. This is because when the temperature reaches a predetermined temperature, the decomposition (degreasing) of the resin proceeds at a stretch. On the other hand, the butyral resin does not burn unless it is combined with oxygen in the atmosphere, and therefore combustion (degreasing) gradually proceeds.

  On the other hand, when trying to obtain a greater restraining force in the unfired ceramic constrained layer, it is better that the powder density of the hardly sinterable ceramic powder contained therein is higher. It is necessary to reduce the amount of binder. Under such circumstances, the butyral resin has a higher strength as a binder than the acrylic resin. Therefore, according to the butyral resin, a relatively high strength can be obtained even in a small amount in the ceramic green sheet serving as the unfired ceramic constraining layer.

  In summary, by using a butyral resin in the unfired ceramic constraining layer, even if it is thinned, the strength of the ceramic green sheet that becomes the unfired ceramic base layer is ensured, and tearing and chipping during handling The generation of defects can be suppressed, and the powder density in the unfired ceramic constraining layer can be increased so that a large restraining force can be obtained. On the other hand, since an acrylic resin excellent in degreasing properties is used in the unfired ceramic base material layer, even if the volume ratio of the unfired ceramic base material layer is increased in the unfired ceramic composite laminate, the binder removal step is performed. It can proceed smoothly, and delamination at the interface between the base material layer and the constraining layer due to residual carbon can be advantageously suppressed.

  In the present invention, when the unfired composite laminate has a cavity structure and the unfired ceramic constraining layer is provided at least on the bank of the cavity, the multilayer is free of undesired deformation or little deformation in the cavity. A ceramic substrate can be obtained.

Further, according to the present invention, in the firing step, the unfired glass component generated in the ceramic base layer penetrates the unfired ceramic constraining layer, thereby, the green ceramic constraining layer is densified, The mechanical strength of the obtained multilayer ceramic substrate can be increased.

Further, according to the present invention, the unfired ceramic constraining layer is thinner than the unfired ceramic base material layer, and the thickness of the unfired ceramic constraining layer is 1 with respect to the unfired ceramic base material layer having a thickness of 20 to 200 μm. because are 10 .mu.m, in the baking step, it is possible to produce a glass component in an amount sufficient in the green ceramic substrate layers, the entire region of the green ceramic constraining layer, such glass components easily penetrate Can be made.

  When the low-temperature sintered ceramic powder contained in the unfired ceramic substrate layer contains ceramic powder and glass powder, a glass component can be easily generated in the firing step.

  When a conductor pattern mainly composed of gold, silver or copper is formed on the unfired composite laminate, such a conductor pattern can be fired simultaneously with firing to obtain a multilayer ceramic substrate, and Since the electric resistance of the conductor pattern can be lowered, insertion loss due to the electric resistance of the conductor pattern can be reduced.

  According to the composite green sheet for producing a multilayer ceramic substrate according to the present invention, an unfired composite laminate produced for producing a multilayer ceramic substrate can be efficiently produced.

  FIG. 1 is a cross-sectional view showing a first example of a multilayer ceramic substrate manufactured by applying the manufacturing method according to the present invention.

  A multilayer ceramic substrate 1 shown in FIG. 1 includes a plurality of stacked base material layers 2, a constraining layer 3 positioned so that at least one main surface thereof is in contact with the base material layer 2, A composite laminate 5 having a laminate structure including a conductor film 4 formed so as to extend in the main surface direction is provided. Inside the composite laminate 5, several via-hole conductors 6 are formed so as to penetrate the specific base material layer 2 and the constraining layer 3 in the thickness direction while being electrically connected to a specific one of the conductor films 4. Is provided. In this embodiment, the base material layers 2 and the constraining layers 3 are alternately laminated. Further, the constraining layer 3 is made thinner than the base material layer 2.

  The base material layer 2 is composed of a low-temperature sintered ceramic material such as glass ceramic. On the other hand, the constraining layer 3 is constituted by an aggregate of hardly sinterable ceramic powders such as alumina and zirconia, which are not substantially sintered at the sintering temperature of the low-temperature sintered ceramic material constituting the base material layer 2. . That is, the constraining layer 3 is in a state in which the glass component generated in the base material layer 2 penetrates into the constraining layer 3 and the hardly sinterable ceramic powders are fixed to each other.

  Conductive patterns such as the conductive film 4 and the via-hole conductor 6 are obtained by sintering a conductive paste. The conductive component contained in the conductive paste is preferably composed mainly of gold, silver, or copper. Is used.

  On the upper main surface of the composite laminate 5, chip components 8 and 9 as surface mount electronic components are mounted. Chip components 8 and 9 are electrically connected to conductor film 4 formed on the upper main surface of composite laminate 5. The conductor film formed on the lower main surface of the composite laminate 5 is used to electrically connect and mechanically fix the multilayer ceramic substrate 1 to the motherboard when the multilayer ceramic substrate 1 is mounted on the motherboard. Used for.

  The multilayer ceramic substrate 1 is manufactured as follows.

  First, a raw material of the composite laminate 5 shown in FIG. 1 is prepared. The raw state of the composite laminate 5, ie, the unfired composite laminate 5a is shown in FIG. Referring to FIG. 2, the unfired composite laminate 5 includes an unfired ceramic base layer 2 a that becomes the base layer 2, an unfired ceramic constrained layer 3 a that becomes the constraining layer 3, and an unfired that becomes the conductor film 4. A conductive film 4 a and an unfired via-hole conductor 6 a that becomes the via-hole conductor 6 are provided.

  The unfired ceramic base layer 2a includes a low-temperature sintered ceramic powder made of, for example, ceramic powder and glass powder and a first organic binder, and an acrylic resin is used as the first organic binder. The unfired ceramic constraining layer 3a includes the hard-to-sinter ceramic powder and the second organic binder as described above, and a butyral resin is used as the second organic binder. As described above, the unfired conductor film 4a and the unfired via-hole conductor 6a are preferably made of a conductive paste containing a conductive component mainly composed of gold, silver, or copper.

  In order to produce the unfired composite laminate 5a, typically, a green sheet for the base layer to be the unfired ceramic base layer 2a and a green sheet for the constraining layer to be the unfired ceramic constraining layer 3a are prepared. Is done. In this case, for example, the constraining layer green sheet may be formed on the base layer green sheet, or may be prepared in the state of a composite green sheet obtained by the reverse forming order. Details of the composite green sheet will be described later. Next, in order to form an unfired via-hole conductor 6a in a predetermined green sheet or composite green sheet, a through hole is provided, and a conductive paste is filled therein, and an unfired conductor film 4a is formed. A conductive paste is printed. And a green sheet or a composite green sheet is laminated | stacked in a predetermined order, and the unbaking composite laminated body 5a is obtained by crimping | bonding.

  Next, in order to remove the acrylic resin as the first binder and the butyral resin as the second binder, the unfired composite laminate 5a is, for example, at a temperature of 300 to 500 ° C. in the air. The binder is removed.

  In the binder removal process described above, since the unfired ceramic base material layer 2a occupying most of the volume of the unfired composite laminate 5a uses an acrylic resin excellent in degreasing properties as a binder, the binder removal treatment is smoothly performed. Can proceed.

  Next, the unfired composite laminate 5a is fired. The temperature condition given in this firing step is that the low-temperature sintered ceramic powder in the unfired ceramic base layer 2a is sintered as a result of the firing step, but the hardly sinterable ceramic powder in the unfired ceramic constraining layer 3a is substantially Is chosen not to sinter.

  Due to the firing step, a part of the glass component contained in the unfired ceramic base layer 2a diffuses or flows throughout the unfired ceramic constraining layer 3a, thereby causing poor sinterability contained in the unfired ceramic constraining layer 3a. It is preferred that the ceramic powders adhere to each other and as a result, the green ceramic constraining layer 3a is densified. Thus, in order to make it easy for the limited amount of glass component contained in the unfired ceramic base layer 2a to permeate the entire area of the unfired ceramic constraining layer 3a, the unfired ceramic base layer 2a It is preferable that the thickness of the unfired ceramic constraining layer 3a is 1 to 10 μm while the thickness is 20 to 200 μm.

  In the firing step, the hardly sinterable ceramic powder contained in the unfired ceramic constraining layer 3a is not substantially sintered, so that no substantial shrinkage occurs in the unfired ceramic constraining layer 3a or constraining layer 3. Accordingly, the unfired ceramic constraining layer 3a to constraining layer 3 exerts a shrinkage suppressing action on the unfired ceramic base material layer 2a to the base material layer 2 and suppresses shrinkage in the main surface direction.

  Here, since the butyral resin as the organic binder contained in the unfired ceramic constraining layer 3a can give a predetermined strength to the unfired ceramic constraining layer 3a even in a small amount, It should be noted that the powder density of the hardly sinterable ceramic powder can be increased, and therefore a large restraining force can be exerted. From this, it becomes difficult to produce an undesired deformation in the obtained composite laminate 5 after sintering, and the dimensional accuracy can be improved.

  In order to further improve the dimensional accuracy described above, the firing step is performed in a state where the unfired ceramic outer constraining layer 7a is provided on at least one main surface of the unfired composite laminate 5a as indicated by an imaginary line in FIG. You may implement. As in the case of the unfired ceramic constraining layer 3a, the unfired ceramic outer constraining layer 7a includes a non-sinterable ceramic powder and an organic binder, and a butyral resin is preferably used as the organic binder. The thickness of the unfired ceramic outer layer 7a is not particularly limited, but is preferably selected in the range of 50 to 500 μm in consideration of having a sufficient amount of restraint and smooth progress of the binder removal.

  The unfired ceramic outer layer 7a is removed by a method such as ultrasonic cleaning after the firing step. In the unfired composite laminate 5a shown in FIG. 2, the unfired ceramic constraining layer 3a is positioned on the outermost side, but when the unfired ceramic outer constraining layer 7a is provided, the unfired ceramic substrate It is preferable to laminate so that the layer 2a is located on the outermost side.

  Next, chip components 8 and 9 are mounted on the upper main surface of the composite laminate 5, and the multilayer ceramic substrate 1 shown in FIG. 1 is completed.

  FIG. 3 is a cross-sectional view showing a second example of the multilayer ceramic substrate manufactured by applying the manufacturing method according to the present invention. FIG. 4 is a view corresponding to FIG. 2 and a cross-sectional view showing an unfired composite laminate 15a produced in order to obtain the composite laminate 15 provided in the multilayer ceramic substrate 11 shown in FIG. 3 and 4, elements corresponding to those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description is omitted.

  The multilayer ceramic substrate 11 shown in FIG. 3 is characterized in that the composite laminate 15 provided therein has a cavity structure including a flat plate portion 21 and a bank portion 22. A chip component 24 is accommodated and mounted in the cavity 23 provided in the composite laminate 15.

  In order to obtain the unfired composite laminate 15a, the same steps as in the case of the unfired composite laminate 5a described above were performed except that a green sheet provided with a through hole to be the cavity 23 was partially laminated. Moreover, the same binder removal process and baking process are implemented, and the sintered composite laminated body 15 is obtained.

  In the unfired composite laminate 15a, the unfired ceramic constraining layer 3a is provided on both the flat plate portion 21 and the bank portion 22, but in this embodiment, the unfired ceramic constraining layer 3a is provided on the bank portion 22. It is important that Therefore, at least a part of the unfired ceramic constraining layer 3a provided on the flat plate portion 21 may be omitted. By providing the unfired ceramic constraining layer 3a at least on the bank 22, it is possible to effectively prevent undesired deformation of the cavity 23 that is easily deformed during firing.

  In producing the multilayer ceramic substrate 1 or 11 described above, one green sheet to be each of the base material layer 2 and the constraining layer 3 is prepared to produce the green composite laminate 5a or 15a in a raw state. Although it can be considered to be laminated, it is preferably prepared in a state of a composite green sheet as described below, and the unfired composite laminate 5a or 15a is produced using this composite green sheet.

  5 to 8 show some examples of composite green sheets in cross-sectional views. 5 to 8, elements corresponding to those shown in FIG. 1 are denoted by the same reference numerals. Further, in FIGS. 5 to 8, illustration of the conductor film and the via hole conductor is omitted.

  5 to 8 show a carrier film 25 made of, for example, polyethylene terephthalate. The carrier film 25 is used, for example, when a ceramic slurry to be the unfired ceramic base layer 2a is formed into a sheet shape, and facilitates handling of the green sheet after being formed. The carrier film 25 is peeled off and removed at the stage where the lamination process for obtaining the unfired composite laminate 5a or 15a is completed.

  In the composite green sheet 26 shown in FIG. 5, a green sheet to be the unfired ceramic base material layer 2a is formed on the carrier film 25, and then dried as necessary, and then the unfired ceramic base material layer. This is obtained by forming a green sheet to be the unfired ceramic constraining layer 3a on 2a. In the case of this composite green sheet 26, although not shown, it is easy to form a conductor film on the unfired ceramic constraining layer 3a.

  The green sheet forming to be the unfired ceramic base layer 2a and the green sheet forming to be the unfired ceramic constraining layer 3a may be performed in a series of steps. After forming the green sheet to be 2a, the carrier film 25 holding the green sheet to be the unfired ceramic base layer 2a is once wound into a roll shape, and then the unfired ceramic base layer 2a and The green sheet to be formed may be drawn together with the carrier film 25, and the green sheet to be the unfired ceramic constraining layer 3a may be formed. This also applies to the case of other composite green sheets 27 to 29 described with reference to FIGS.

  In the composite green sheet 27 shown in FIG. 6, a green sheet to be the unfired ceramic constraining layer 3a is formed on the carrier film 25, and then dried as necessary, and then the unfired ceramic base layer 2a. It is obtained by forming a green sheet to be. In the case of this composite green sheet 27, although not shown, it is easy to form a conductor film on the unfired ceramic base layer 2a.

  Note that the composite green sheet 26 shown in FIG. 5 and the composite green sheet 27 shown in FIG. 6 have the same laminated structure when the carrier film 25 is removed.

  The composite green sheet 28 shown in FIG. 7 includes a green sheet to be the unfired ceramic constraining layer 3a, a green sheet to be the unfired ceramic base layer 2a, and the unfired ceramic constraining layer 3a on the carrier film 25. The green sheet to be obtained is obtained by forming in this order. In the case of this composite green sheet 28, although not shown, it is easy to form a conductor film on the unfired ceramic constraining layer 3a.

  The composite green sheet 29 shown in FIG. 8 has, on the carrier film 25, a green sheet to be the unfired ceramic base layer 2a, a green sheet to be the unfired ceramic constraining layer 3a, and the unfired ceramic base layer 2a. The green sheet to be obtained is obtained by molding in this order. In the case of this composite green sheet 29, although not shown, it is easy to form a conductor film on the unfired ceramic base layer 2a.

  The composite green sheets 26 to 29 described above can be used to produce the unfired composite laminate 5a or 15a by using any of these alone or using any of these in combination. it can. For example, the unfired composite laminate 5a or 15a can be manufactured by combining the composite green sheet 26 or 27 and the composite green sheet 28 or 29. Further, by laminating the composite green sheet 28 and the composite green sheet 29, the unfired composite laminate 5a or 15a can be produced.

  While the present invention has been described with reference to the illustrated embodiment, various other modifications are possible within the scope of the present invention.

  For example, in the multilayer ceramic substrate 1 shown in FIG. 1 and the multilayer ceramic substrate 11 shown in FIG. 3, the base layer 2 and the constraining layer 3 are alternately laminated. At least one main surface may be positioned so that not the constraining layer 3 but another base material layer 2 is in contact therewith.

  Next, experimental examples carried out to confirm the effects of the present invention will be described. FIG. 9 is a view showing a cross-sectional structure of an unfired composite laminate 31 produced in this experimental example. The unfired composite laminate 31 includes an unfired ceramic constraining layer 32 having a thickness of 5 μm, an unfired ceramic base layer 33 having a thickness of 100 μm formed by sandwiching the unfired ceramic constraining layer 32, and an unfired ceramic base layer. 33 is formed of a 100 μm-thick unfired ceramic outer constraining layer 34 provided on the outside of each.

  In the unfired ceramic base layer 33, a mixed powder of alumina powder and Si—Ca—B—Al glass powder was used as the low-temperature sintered ceramic powder. In the unfired ceramic constraining layer 33 and the unfired ceramic outer constraining layer 34, alumina powder was used as the hardly sinterable ceramic powder.

  Further, the resin used as the organic binder in the unfired ceramic base material layer 33 is shown in the column “Base material layer” in Table 1. Similarly, the resin used as the organic binder in the unfired ceramic constraining layer 32 and the unfired ceramic outer constraining layer 34 is shown in the column “Constrained Layer” in Table 1.

  Next, after cutting the unfired composite laminate 31 to a desired size, a binder removal step and a firing step were performed to obtain a sintered composite laminate. In the firing step, the low-temperature sintered ceramic powder contained in the unfired ceramic base layer 33 is sintered, but the hardly sinterable ceramic powder contained in the unfired ceramic constraining layer 32 and the unfired ceramic outer constraining layer 34 is substantially. This was carried out at a temperature at which sintering was not performed, that is, a temperature of 900 ° C.

  After the firing step, the unfired ceramic outer constraining layer 34 was removed by ultrasonic cleaning.

  The cross section of the composite laminate after firing thus obtained was observed, and the ratio of the number of samples in which delamination or bubbles occurred was determined. The results are shown in Table 2.

  As can be seen from Table 2, delamination or bubbles occurred in Comparative Examples 2 and 3, and neither delamination nor bubbles occurred in Example and Comparative Example 1. As can be seen from Table 1, in the unfired ceramic substrate layer 33, delamination or bubbles are generated when a butyral resin is used, and any of delamination and bubbles is generated when an acrylic resin is used. Neither occurred.

  Next, with respect to Example and Comparative Example 1 in which neither delamination nor bubbles occurred, in order to evaluate the defect occurrence rate of the green sheet serving as the unfired ceramic constraining layer 32, the through holes to be cavities were punched. The ratio of the sample in which defects were generated during the formation of the through hole was determined. The results are shown in Table 3.

  As can be seen from Table 3, in the green sheet serving as the unfired ceramic constraining layer 32, defects occurred in Comparative Example 1 using an acrylic resin, but no defects occurred in an example using a butyral resin. .

It is sectional drawing which shows the 1st example of the multilayer ceramic substrate manufactured by applying the manufacturing method which concerns on this invention. It is sectional drawing which shows the unbaking composite laminated body 5a produced in order to obtain the composite laminated body 5 with which the multilayer ceramic substrate 1 shown in FIG. 1 is equipped. It is sectional drawing which shows the 2nd example of the multilayer ceramic substrate manufactured by applying the manufacturing method concerning this invention. It is sectional drawing which shows the unbaking composite laminated body 15a produced in order to obtain the composite laminated body 15 with which the multilayer ceramic substrate 11 shown in FIG. 3 is equipped. It is sectional drawing which shows the 1st example of the composite green sheet used in order to produce a raw laminated body. It is sectional drawing which shows the 2nd example of the composite green sheet used in order to produce a raw laminated body. It is sectional drawing which shows the 3rd example of the composite green sheet used in order to produce a raw laminated body. It is sectional drawing which shows the 4th example of the composite green sheet used in order to produce a raw laminated body. It is a figure which shows the cross-section of the unbaking composite laminated body 31 produced in the experiment example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 Multilayer ceramic substrate 2 Base material layer 2a, 33 Unbaked ceramic base material layer 3 Constrained layer 3a, 32 Unfired ceramic constrained layer 4 Conductor film 5,15 Composite laminated body 5a, 15a, 31 Unfired composite laminated body 6 Via hole conductor 7a, 34 Unfired ceramic outer constraining layer 8, 9, 24 Chip component 21 Flat plate portion 22 Bank portion 23 Cavity 26-29 Composite green sheet

Claims (7)

A plurality of laminated unfired ceramic substrate layers including a low-temperature sintered ceramic powder and a first organic binder, and at least one main surface thereof is positioned in contact with the unfired ceramic substrate layer, and is difficult Producing a green composite laminate comprising a green ceramic constraining layer comprising a sinterable ceramic powder and a second organic binder;
A binder removal step for removing the binder from the unfired composite laminate in order to remove the first and second binders;
Next, the low-temperature sintered ceramic powder in the green ceramic base layer is sintered in the green composite laminate, but the hardly-sinterable ceramic powder in the green ceramic constrained layer is substantially sintered. And firing at a temperature that does not ,
In the step of producing the green composite laminate, the thickness of the green ceramic base layer is 20 to 200 μm, the thickness of the green ceramic constraining layer is 1 to 10 μm,
The firing step includes a step of causing the glass component generated in the unfired ceramic base layer to penetrate into the unfired ceramic constraining layer, thereby densifying the unfired ceramic constraining layer.
In the method of manufacturing a multilayer ceramic substrate,
A multilayer ceramic, wherein an acrylic resin is used as the first organic binder in the unfired ceramic base layer, and a butyral resin is used as the second organic binder in the unfired ceramic constraining layer A method for manufacturing a substrate.   The step of producing the unfired composite laminate has the cavity structure including a flat plate portion and a bank portion, and the unfired ceramic laminate layer is provided at least on the bank portion. The manufacturing method of the multilayer ceramic substrate of Claim 1 provided with the process to produce. Before the binder removal step, on the at least one main surface of the unfired composite laminate, a step of providing an unfired ceramic outer constraining layer containing a non-sinterable ceramic powder and an organic binder, and after the firing step, the unfired further comprising a step of removing the ceramic outer constraining layer, a method for manufacturing a multilayer ceramic substrate according to claim 1 or 2. The low-temperature sintering ceramic powder comprises a ceramic powder and glass powder, a method for manufacturing a multilayer ceramic substrate according to any one of claims 1 to 3. The step of producing the green composite laminate includes a step of forming a conductor pattern mainly composed of gold, silver, or copper in relation to the green ceramic base layer and / or the green ceramic constraining layer. A method for producing a multilayer ceramic substrate according to any one of claims 1 to 4 , further comprising: After the firing step, the at least on one main surface of the unfired obtained by firing the composite laminate composite laminate, further comprising a step of mounting a surface mount electronic device, any of claims 1 to 5 A method for producing a multilayer ceramic substrate according to claim 1. A composite green sheet for producing a multilayer ceramic substrate held by a carrier film,
A green ceramic substrate layer having a thickness of 20 to 200 μm , comprising a low-temperature sintered ceramic powder and a first organic binder;
An unfired ceramic constraining layer having a thickness of 1 to 10 μm , which is positioned so that at least one main surface thereof is in contact with the unfired ceramic base material layer, and includes a hardly sinterable ceramic powder and a second organic binder. ,
In a firing step for obtaining a multilayer ceramic substrate, the glass component generated in the unfired ceramic base layer is infiltrated into the unfired ceramic constraining layer, thereby densifying the unfired ceramic constraining layer. Was
An acrylic resin is used as the first organic binder in the unfired ceramic base layer, and a butyral resin is used as the second organic binder in the unfired ceramic constraining layer,
Composite green sheet for making multilayer ceramic substrates.

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