JP2005064240A - Manufacturing method of ceramic multilayer substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, when thin laminates are connected through pressure on a support member and are peeled off from the support member, the laminates are bent and elongated, and a ceramic multilayer substrate obtained by calcining the deformed laminates is also inevitably deformed. <P>SOLUTION: A reinforcing sheet taking as chief components burned out upon calcining is added to the laminates of a ceramic green sheet, and is peeled off from the support member after being thickened as the whole thereof. The reinforcing sheet is manufactured using resin and a binder for example which is vaporized and burned out during the calcination. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a ceramic multilayer substrate.

  Patent Document 1 discloses an example of a conventional method for manufacturing a ceramic multilayer substrate. Patent Document 1 proposes a manufacturing method and a manufacturing apparatus that continuously perform a series of steps for manufacturing a multilayer ceramic electronic component. The work contents in each step are as follows.

  First, a ceramic green sheet formed on a carrier film is prepared.

  Second, a conductive paste is printed or embedded on the ceramic green sheet to form an electrode.

  Third, with the carrier film attached, the ceramic green sheet is laminated on the table, and the laminate is prepared by sequentially pressing and peeling the carrier film one by one.

Finally, the obtained laminated body is peeled off from the table, fired to produce a substrate, and external electrodes are formed on the substrate to produce a laminated ceramic electronic component.
Japanese Patent No. 2504277

  In response to the recent demand for downsizing and low-profile electronic components, there is an increasing tendency to reduce the size and height of the substrate on which electronic components are based. Of course, even a small and low-profile substrate needs to be provided so that its shape is not deformed.

  In order to reduce the thickness of the substrate, it is necessary to reduce the thickness of the raw laminate before firing. Laminates are generally produced by stacking and pressing a plurality of green sheets on a support member such as a support base. However, if the laminate is peeled off from the support member after crimping, the laminate will be thin. The thinner the film, the more difficult it is to peel off. In the worst case, there is a possibility that the laminate is deformed by bending or stretching at the time of peeling. If the laminate is deformed, the substrate obtained through subsequent firing is inevitably deformed. Therefore, an object of the present invention is to provide a manufacturing method capable of producing a ceramic multilayer substrate that is not deformed even if the thickness is small.

  The method for producing a ceramic multilayer substrate according to the present invention includes a step of preparing a plurality of ceramic green sheets, a step of preparing a desired number of reinforcing sheets mainly composed of components that are burned off during firing, and the ceramic green sheets. It is characterized by comprising a step of laminating and press-bonding the reinforcing sheet on a support member to produce a laminate, a step of peeling the laminate from the support member, and a step of firing the laminate. Speaking from the above-mentioned purpose, this reinforcing sheet is temporarily laminated at the stage of the raw laminate, and should not be a component of the board at the stage of becoming a board, but should increase the thickness of the board. It is not a thing. Therefore, for example, it is formed using a material that is vaporized and burned during firing. Even if some of the components contained in the reinforcing sheet are not burned out, some of the components can be easily removed without adhering to the substrate.

  If the manufacturing method of the ceramic multilayer substrate of this invention is used, even if the thickness of the desired laminated body is a thin thing less than 500 micrometers, for example, thickness can be increased by adding a reinforcement sheet temporarily. For this reason, the rigidity of the whole laminated body can be increased, the ease of peeling from the table can be enhanced, and deformation of the laminated body that can occur at the time of peeling from the table can be prevented. As a result, a ceramic multilayer substrate having a desired thin thickness and no deformation is finally obtained.

(Example 1)
FIG. 1 is a perspective view for illustrating one embodiment of the manufacturing method of the present invention, and sequentially showing the manufacturing procedure up to the completion of the ceramic multilayer substrate 2.

  First, as shown in FIG. 1A, a ceramic green sheet 11a is prepared.

  In this embodiment, the ceramic green sheet 11a is obtained by applying a slurry prepared by dispersing barium titanate-based dielectric particles in an acrylic binder onto the carrier film 12 and drying it. The size is 10 cm in length and width, and the thickness is 2.5 μm. A Pd-based electrode paste is printed on the ceramic green sheet 11a to form a wiring circuit. A total of 100 ceramic green sheets 11a including the carrier film 12 are prepared.

  Next, as shown in FIG. 1B, a reinforcing sheet 13a is prepared.

  In this embodiment, the slurry that is the basis of the reinforcing sheet 13a is 20% by volume of the polypropylene resin powder, 50% by volume of the binder, and the remaining 30% by volume of the plasticizer and the solvent, assuming that the total volume of the slurry is 100%. Kneaded with. This slurry is applied to a carrier film, dried, and a reinforcing sheet 13a having a length of 10 cm and a thickness of 250 μm is prepared. When the reinforcing sheet 13a is dried to form a sheet, the polypropylene resin, the binder, and the plasticizer remain, and the solvent is vaporized and disappears. In this embodiment, one reinforcing sheet 13a is prepared.

  Next, as shown in FIG.1 (c), the laminated body 1 is produced.

  First, the support sheet 14 having a surface roughness Ra of 15 μm is arranged on the support table 15, and the reinforcing sheet 13 a is arranged on the support sheet 14. Next, the ceramic green sheet 11a is laminated on the reinforcing sheet 13a with the carrier film 12 facing upward, and is pressed by applying a pressure of 35 kgf / cm 2 for 3 seconds, and the carrier film 12 is peeled off. This series of operations of lamination, pressure bonding, and peeling is repeated 100 times to produce a substantially rectangular parallelepiped laminated body 1 in which the reinforcing sheet 13a is laminated on the lowermost layer and 100 ceramic green sheets 11a are laminated thereon. In this laminate 1, the ceramic green sheet 11 a has a total thickness of 250 μm and is very thin. However, since the thickness of the reinforcing sheet 13 a is added to 250 μm, the thickness of the entire laminate 1 is 500 μm.

  In this embodiment, the support base 15 and the support sheet 14 are used as an example of a support member that supports the pressure bonding of the reinforcing sheet 13a and the ceramic green sheet 11a. It may be supported. Further, as in this embodiment, a method of laminating a sheet on the upper surface of the support member and pressurizing it from above may be used. Conversely, a method of laminating a sheet from the lower side to the lower surface of the support member and pressing from below. Absent. Further, as in this embodiment, the pressure may be applied every time one sheet is stacked, or may be pressed once after all the sheets are stacked.

  Next, as shown in FIG. 1 (d), the laminate 1 including the support sheet 14 is first removed from the support base 15, and then the laminate 1 is peeled from the support sheet 14. Since the laminated body 1 has an increased thickness of 500 μm, it has a higher rigidity than the thickness of only the ceramic green sheet 11a, which is 250 μm. For this reason, even if it bends somewhat during peeling, the stress which returns to the original after the peeling ends works, and does not deform. Further, when the thickness is increased, the peeling operation itself is facilitated. Whether it is peeled off manually or using a mechanical device, the thicker one is easier to handle. If the ease of peeling increases, the force applied when peeling can be easily applied evenly over a wide range without concentrating on one point of the laminate, and the factor of deformation can be eliminated.

  The adhering matter 16 shown in FIG. 1D shows a part of the reinforcing sheet 13a that has adhered to the support sheet 14 during peeling. However, since the reinforcing sheet 13a is burnt down in firing described later and does not originally become a part of the substrate, there is no problem even if a part of the reinforcing sheet 13a is missing. In other words, if the reinforcing sheet 13a is not laminated in the lowermost layer, there is a possibility that a part of the ceramic green sheet 11a to be a substrate or an electrode paste formed on the surface adheres to the support sheet 14. Occurs. For this reason, it is preferable to place the reinforcing sheet 13a in the lowermost layer of the laminate as in this embodiment, which leads to prevention of missing of the ceramic green sheet 11a and the electrode paste.

  Moreover, the lower surface of the laminated body 1 which is in contact with the support sheet 14 may be considerably roughened during pressure bonding or peeling. In particular, as in the present example, when pressing is performed each time one ceramic green sheet is laminated, the number of times of pressure application increases as the lowermost sheet of the laminated body adheres more strongly to the support sheet 14, and at the time of peeling. The possibility of rough surfaces increases. Even in such a case, if the reinforcing sheet 13a is placed in the lowermost layer, even if the surface becomes rough, it will eventually be burned out, so that there is no influence on the desired substrate.

  Next, the peeled laminate 1 is fired at about 1000 ° C.

During firing, all the polypropylene resin, binder, and plasticizer contained in the reinforcing sheet 13a are burned off. As a result, a ceramic multilayer substrate 2 as shown in FIG.
(Example 2)
FIG. 2 is a perspective view for explaining another embodiment of the manufacturing method of the present invention, and sequentially showing the manufacturing procedure up to the completion of the ceramic multilayer substrate 4. The same reference numerals as those in FIG. 1 are assigned to the same components in FIG. 1 in FIG. Also, those performing the same work as the work shown in FIG. 1 are omitted from FIG.

  First, as in the first embodiment, 100 ceramic green sheets 11a are prepared.

  Next, as shown in FIG. 2A, a reinforcing sheet 13b is prepared.

  In this example, the slurry that is the base of the reinforcing sheet 13b is 30% by volume of the polypropylene resin powder, 10% by volume of alumina powder, 20% by volume of the binder, and 40% by volume of the remaining volume, assuming that the total volume of the slurry is 100%. Is kneaded at a ratio of plasticizer and solvent. This slurry is applied to a carrier film, dried, and a reinforcing sheet 13b having a length of 3 cm square and a thickness of 250 μm is prepared. At the stage of becoming a sheet, polypropylene-based resin, alumina, binder and plasticizer remain in the reinforcing sheet 13b, and the solvent is vaporized and disappears. In this embodiment, two reinforcing sheets 13a are prepared.

  This alumina powder is an example of an inorganic filler that does not sinter at the firing temperature described later, and is effective in suppressing the shrinkage in the surface direction that occurs when the ceramic green sheet is fired. It may be contained in the reinforcing sheet.

  Next, as shown in FIG. 2B, the laminate 3 is manufactured.

  Similar to Example 1 described above, the support sheet 14 having a surface roughness Ra of 15 μm is disposed on the support base 15, and one reinforcing sheet 13 b is disposed on the support sheet 14. Next, the ceramic green sheets 11a are laminated, pressure is applied at a pressure of 35 kgf / cm 2 for 3 seconds, and the carrier film 12 is peeled off. This series of operations of lamination, pressure bonding, and peeling is repeated 100 times. Finally, one reinforcing sheet 13b is laminated and pressure-bonded. As a result, the substantially rectangular parallelepiped laminated body 3 in which the reinforcing sheet 13b is provided in the lowermost layer and the uppermost layer and 100 ceramic green sheets 11a are laminated therebetween is produced. If the thickness of the laminate 3 is only the ceramic green sheet 11a, the thickness is 250 μm, which is very thin. However, the thickness of the reinforcing sheet 13b is added to add 500 μm. 750 μm.

  Next, the laminate 3 including the support sheet 14 is first removed from the support base 15, and then the laminate 3 is peeled from the support sheet 14. Since the laminate 3 has an increased thickness of 750 μm, it can be easily peeled off without being deformed.

  Next, the peeled laminate 3 is fired at about 1000 degrees. FIG. 2C shows the ceramic multilayer substrate 4 immediately after firing, and shows a state in which the alumina powder 18 is on the upper surface.

  During firing, the polypropylene resin, binder, and plasticizer contained in the reinforcing sheet 13b are burned away, but the alumina powder 18 remains without being burned. However, the alumina powder 18 does not adhere to the substrate, that is, does not neck with the ceramic particles contained in the ceramic sheet 11a, and remains in a powder state on the upper surface of the substrate.

  Whether the alumina powder 18 adheres to the substrate is determined by the content of the alumina powder in the reinforcing sheet 13b. In this example, the alumina powder contains only 10% by volume in the slurry stage, and a large amount of binder or resin exists between the ceramic particles and the alumina particles, so there is no contact between the particles. Become. During firing, the binder and the resin gradually burn out, and the distance between the particles approaches, but if the content is 30% by volume or less, it does not reach necking and does not adhere to the substrate. Since the alumina powder 18 is simply dried to return to the original powder state and is only on the upper surface of the substrate, it can be easily removed with a brush or the like.

  On the contrary, when the proportion of the alumina powder 18 in the reinforcing sheet 13b exceeds 30% by volume, the proportion of the alumina powder 18 and the ceramic powder contained in the ceramic green sheet 11a in contact with each other during firing is increased, and the particles are necked. As a result, the alumina powder 18 adheres to the substrate. The fixed alumina particles cannot be easily removed, and a work process is required for cutting with a dicer or the like.

Next, the alumina powder 18 is removed with a brush or the like, and the ceramic multilayer substrate 4 as shown in FIG.
(Example 3)
FIGS. 3A and 3B are perspective views illustrating a manufacturing procedure up to the completion of the ceramic multilayer substrate 6 step by step for explaining still another embodiment of the manufacturing method of the present invention. Components similar to those in FIGS. 1 and 2 are given the same reference numerals in FIG. Also, those performing the same work as the work shown in FIGS. 1 and 2 are omitted from FIG.

  First, as in Example 1 described above, a ceramic green sheet is prepared. However, the thickness is 50 μm. Among these, seven ceramic green sheets 11b are provided with through holes 19a of 5.2 mm × 6.6 mm near the center. Similarly, the five ceramic green sheets 11c are provided with through holes 19b of 4.5 mm × 5.5 mm. This through hole becomes a cavity when it becomes a substrate. The four ceramic green sheets 11d are not provided with through holes and are left as they are.

  Next, a reinforcing sheet 13c containing alumina powder is prepared as in Example 2 described above. However, the thickness is 50 μm and 6 sheets are prepared.

  Next, as shown in FIG. 3B, six reinforcing sheets 13c, four ceramic green sheets 11d, five ceramic green sheets 11c, and seven ceramic green sheets 11b are placed on the support base 15. Sequentially, lamination, pressure bonding, and peeling of the carrier film 12 are performed to produce a laminate 5 in which a cavity is provided on one surface. FIG. 4 is a cross-sectional view assuming that the laminated body 5 is cut along the line AA. This laminated body 5 is provided with a through hole 19 in the center, and a thickness of 300 μm for six reinforcing sheets 13c is added to a thickness of 800 μm for 16 ceramic green sheets, resulting in a total thickness of 1100 μm. . The thickness of the bottom plate 21 is 500 μm.

  In the first embodiment, one reinforcing sheet having a thickness of 250 μm is added. However, in this embodiment, six reinforcing sheets having a thin thickness of 50 μm are stacked. A cavity is provided on one surface of the laminate produced in this example, and if the total thickness of the bottom plate is 330 μm or more, even if one thick reinforcing sheet is added, the thickness is thin. You may stack multiple things.

  Next, as shown in FIG. 3C, first, the laminate 5 including the support sheet 14 is removed from the support base 15, and then the laminate 5 is peeled from the support sheet 14.

  Next, the peeled laminate 5 is fired at about 1000 degrees. FIG. 3D shows the ceramic multilayer substrate 6 in which the cavity 20 after firing is formed. FIG. 5 is a cross-sectional view assuming that the ceramic multilayer substrate 6 is cut along the line BB.

  Such a laminated body provided with a cavity having a thin bottom plate is more likely to be deformed or stretched in peeling from the support sheet than a laminated body having a substantially rectangular parallelepiped shape. Therefore, adding the reinforcing sheet of the present invention to the laminate having such a shape increases the thickness of the thin bottom plate portion, and is particularly effective in preventing deformation during peeling. In this embodiment, the reinforcing sheet contains alumina powder. When the laminated body provided with the cavities is fired, the deformation of the cavity bottom 22 is particularly remarkable. For this reason, it is preferable to contain the alumina powder for suppressing the shrinkage | contraction behavior of a surface direction.

  Further, in this embodiment, the reinforcing sheet is laminated only on the lowermost layer of the laminated body 5, so that the alumina powder does not adhere to the substrate as in the above-described Example 2, but temporarily adheres to the bottom surface of the substrate 6. If it is, it can be easily removed with a brush or the like.

The reinforcing sheet of the present invention is effective when the laminate is substantially rectangular parallelepiped and has a thickness of 500 μm or more, and when a cavity is provided, the bottom plate has a thickness of 330 μm or more, particularly when peeling from the support member. There is. The experimental results that provided the basis for this number are listed below.
(Experiment 1)
A reinforcing sheet was added to the ceramic sheet laminate (thickness 250 μm) described in Example 1 to obtain a substantially rectangular parallelepiped laminate having a total thickness of 250, 350, 420, 500, 580, 660, and 740 μm. After the laminate was peeled from the support member, a cut line (sub-substrate dividing line) was inserted and defined as NG when shifted from the desired position by 40 μm or more, and the relationship between the laminate thickness and the NG ratio was investigated.

When the total thickness of the laminate is larger than 500 μm, the cut line misalignment defect is greatly reduced. Since the cut line deviation largely depends on whether or not the laminate is deformed, it can be determined that if there is a thickness of 500 μm or more, it is effective in preventing deformation that may occur at the time of peeling from the support member.
(Experiment 2)
The thickness of the reinforcing sheet was applied to the ceramic sheet laminate (total thickness 800 μm, bottom plate thickness 200 μm) described in Example 3 to produce a laminate provided with bottom plate total thickness 200, 280, 330, 380, 430, 530 μm. did.

  After this press, the maximum height difference of the bottom surface (component mounting surface) inside the cavity was measured.

In the region where the total thickness of the bottom plate is 330 μm or more, it can be judged that the reduction in the maximum height difference of the cavity component mounting surface is remarkable.
(Experiment 3)
Moreover, it is said that it is effective to add an inorganic filler at a content of 30% by volume or less to the reinforcing sheet of the present invention for the purpose of suppressing shrinkage in the surface direction of the ceramic layer generated during firing. The higher the volume ratio of alumina powder as an example of the inorganic filler, the higher the effect of suppressing shrinkage. However, when the amount of alumina powder exceeds a certain value, the alumina layer is fixed to the surface of the ceramic multilayer substrate that is the product. It has been found that the fixed alumina layer remains without being removed even in the cleaning step before the plating process, and causes defective plating.

  In this experiment, the volume ratio of alumina in the reinforcing sheet in Example 2 was varied and the number of multilayer substrates on which plating was generated was investigated among the ceramic multilayer substrates produced by firing. Two types of alumina powder having different center particle diameters were used.

  If the alumina volume ratio in the reinforcing sheet is 30% or less, plating failure does not occur.

It is the perspective view which showed the preparation procedure until completion of the ceramic multilayer substrate 2 in steps. (Example 1) It is the perspective view which showed the preparation procedure until completion of the ceramic multilayer substrate 4 in steps. (Example 2) It is the perspective view which showed the preparation procedure until completion of the ceramic multilayer substrate 6 in steps. Example 3 It is sectional drawing of the cavity type laminated body 5. FIG. Example 3 2 is a cross-sectional view of a cavity-type ceramic multilayer substrate 6. FIG. Example 3

Explanation of symbols

1, 3, 5 Laminate 2, 4, 6 Ceramic multilayer substrate 11a to d Ceramic green sheet 12 Carrier film 13a to c Reinforcement sheet 14 Support sheet 15 Support base 16 Deposit 18 Alumina powder 19, 19a to b Through hole 20 Cavity 21 Bottom plate 22 Cavity bottom

Claims (6)

Preparing a plurality of ceramic green sheets;
Preparing a desired number of reinforcing sheets whose main component is a component burned off during firing;
Laminating the ceramic green sheet and the reinforcing sheet on a support member, and pressing to produce a laminate,
Peeling the laminate from the support member;
A method for producing a ceramic multilayer substrate, comprising the step of firing the laminate.   The method for producing a ceramic multilayer substrate according to claim 1, wherein the reinforcing sheet is laminated on a lowermost layer of the laminated body.   3. The method for manufacturing a ceramic multilayer substrate according to claim 1, wherein the laminate has a substantially rectangular parallelepiped shape and a thickness of 500 μm or more.   The method for manufacturing a ceramic multilayer substrate according to claim 2, wherein a cavity is provided on one surface of the laminate, and the thickness of the bottom plate is 330 µm or more.   The method for producing a ceramic multilayer substrate according to any one of claims 1 to 4, wherein the reinforcing sheet comprises a resin, a binder, and a plasticizer.   When the reinforcing sheet is 100% by volume, an inorganic filler that is not sintered at the firing temperature of the laminate is added as a subcomponent at a ratio of 30% by volume or less. The manufacturing method of the ceramic multilayer substrate in any one.

Images