JP6174402B2 - Firing setter and method for producing ceramic laminated substrate - Google Patents

Description

  The present invention relates to a firing setter used when firing a ceramic multilayer substrate such as an LTCC substrate, and a method for producing a ceramic multilayer substrate using the firing setter.

  The LTCC (Low Temperature Co-fired Ceramics) substrate is a kind of ceramic multilayer substrate that uses Ag or Cu, which is a low conduction resistor, as a conductor such as a wiring pattern or a via, and has excellent electrical characteristics. Widely used in various fields as high-frequency circuit boards, in-vehicle ECU boards, and the like.

  Such an LTCC substrate is a firing furnace in which a plurality of green sheets are stacked on a flat firing setter after printing an ultra-fine wiring conductor on a green sheet as a substrate material or drilling a via. It can be manufactured by carrying it in and baking it in a temperature range of about 850 ° C. to 1000 ° C. In that case, since the glass component of the green sheet melts on the surface in the firing step, the melted glass component adheres to the surface of the fired setter, causing a problem that the green sheet and the fired setter are melt-bonded.

  Therefore, conventionally, a technique has been proposed in which irregularities having regularity are formed on the surface of the firing setter that comes into contact with the green sheet, and the contact area between the green sheet and the firing setter is reduced by the irregularities (for example, Patent Documents). 1). When a green sheet is fired using such a firing setter, the warpage and distortion of the green sheet that shrinks during firing is suppressed by the firing setter, while adhesion between the green sheet and the firing setter due to melting of the glass component is prevented by unevenness. can do.

JP 2006-225186 A

  By the way, in the manufacturing process of the ceramic laminated substrate described above, when the green sheet contracts during firing, the conductors such as wiring patterns and vias formed on the outer surface of the green sheet move in the contracting direction. It moves while rubbing against the surface of the firing setter. Here, as in the conventional technique disclosed in Patent Document 1, if irregularities having regularity are provided on the surface of the firing setter, it is possible to suppress adhesion between the green sheet and the firing setter. In addition, the surface of the conductor that shrinks during firing is likely to be rubbed against the convex part of the firing setter, and the conductor is likely to be deformed by rubbing, and this is a major factor that reduces the yield of products, including flaws. It was.

  The present invention has been made in view of the actual situation of the prior art, and the first object thereof is that the conductor exposed on the outer surface of the ceramic multilayer substrate has scratches such as scratches and deformation caused by the scratches. A second object of the present invention is to provide a method for manufacturing a ceramic laminated substrate that can reduce the defect of such conductors.

  In order to achieve the first object, the present invention provides a firing setter for firing a ceramic multilayer substrate in a state where a ceramic multilayer substrate having a conductor formed on the outer surface is placed. A plurality of protrusions are provided on the contact surface, and these protrusions are arranged at positions that do not interfere with the movement trajectory of the conductor accompanying shrinkage during firing of the ceramic laminated substrate.

  When the green sheet, which is the substrate material of the ceramic laminated substrate, is fired using the fired setter having such a configuration, the contact area between the green sheet and the fired setter is reduced by the convex portion, so that the green sheet melts on the surface of the fired setter. Even if the conductor exposed on the outer surface of the green sheet can change its position due to shrinkage during firing, the firing setter's convex part can be arranged at a position where it does not interfere with the movement trajectory of the conductor. For this reason, it is possible to reduce the scratches on the conductor that occur during firing and the deformation of the conductor due to the friction.

  In this case, the ceramic laminated substrate is an LTCC substrate, and the base material of the firing setter is made of a material containing an alumina component and a glass component, and the blending ratio of the glass component is set to a range of 10 to 20%. It is preferable that By adopting such a configuration, since the firing setter is composed of the same alumina component and glass component as the green sheet that is the substrate material of the LTCC substrate, it becomes possible to produce the firing setter at low cost, and the firing setter. Since the blending ratio of the glass component is set to be 10 to 20%, which is considerably lower than that of the LTCC substrate, it is possible to prevent the glass components on the LTCC substrate side and the firing setter side from being melted and bonded during firing.

  In order to achieve the second object, the method for manufacturing a ceramic laminated substrate according to the present invention includes a locus confirmation step for confirming a locus on which the conductor on the outer surface moves with contraction when the green sheet is fired. A green sheet was placed on the setter processing step for processing the firing setter provided with a plurality of convex portions on the surface based on the data obtained in the locus confirmation step, and the firing setter obtained in the setter processing step. A substrate firing step for firing the ceramic laminated substrate in a state, and an arrangement pattern of the convex portions provided on the firing setter does not interfere with a locus of the conductor that moves with contraction in the substrate firing step It has been set to.

  The present invention pays attention to the characteristic that a free contraction type green sheet has a characteristic of contracting radially toward the center during firing. For example, a CAD (Computer Aided Design) is used to connect a conductor arrangement before and after contraction. After obtaining the confirmation data, a firing setter having a plurality of projections was prepared based on the obtained data. When placing and firing a green sheet on the firing setter, Even if the conductor exposed on the surface fluctuates due to shrinkage during firing, the conductor moves in the shrinking direction without contacting the convex portion of the firing setter. Therefore, it is necessary to reduce the contact area between the green sheet and the firing setter with the convex part, and to reduce the scratches on the conductor that occur during firing and the deformation of the conductor due to the rubbing, and to ensure surface smoothness. It is possible to omit polishing in the final step. In this way, it is possible to manufacture a ceramic laminated substrate with a good yield by reducing the defect of conductors.

  In this case, the setter processing step includes a step of producing a metal plate in which an opening corresponding to the convex portion is formed, and pressurizing in a state where the metal plate and a plurality of green sheets are laminated. It includes a process of producing a sheet with a convex part by displacing a part into the opening of a metal plate and a process of producing a fired setter by firing this sheet with a convex part. Can be produced.

  Since the firing setter of the present invention is provided with a plurality of convex portions on the contact surface with the ceramic laminated substrate, the green sheet as the substrate material of the ceramic laminated substrate can be prevented from being melt-bonded to the firing setter, In addition, even if the conductor exposed on the outer surface of the green sheet fluctuates due to shrinkage during firing, the convex portions of the firing setter are arranged at positions that do not interfere with the movement locus of the conductor. It is possible to reduce the abrasion of the conductor and the deformation of the conductor due to the abrasion.

  Further, in the method for manufacturing a ceramic laminated substrate according to the present invention, the movement trajectory before and after the conductor on the outer surface of the green sheet contracts as it is fired is acquired as data in advance, and a plurality of convex portions are formed based on this data. Since the firing setter provided was prepared, when the green sheet was actually fired using such a firing setter, even if the conductor was displaced due to shrinkage during firing, the conductor was a convex part of the firing setter. It moves in the contraction direction without touching. Therefore, the contact area between the green sheet and the firing setter can be reduced by the convex portion, and the conductor can be scratched during firing and the deformation of the conductor due to rubbing can be reduced. Can be manufactured.

It is explanatory drawing which shows the baking process of the ceramic laminated substrate which concerns on the example of embodiment. It is explanatory drawing which shows the contraction state of the green sheet in the baking process of FIG. It is a flowchart which shows the manufacturing process of the ceramic laminated substrate which concerns on the embodiment. It is explanatory drawing which shows the preparation process of the baking setter in the setter processing process in FIG.

  DESCRIPTION OF EMBODIMENTS An embodiment of the invention will be described with reference to the drawings. As shown in FIG. 1, a fired setter 1 according to this embodiment example has a plurality of convex portions 3 on a contact surface with an LTCC substrate 2 that is a ceramic laminated substrate. The LTCC substrate 2 is manufactured using the firing setter 1.

  The green sheet 4 which is a substrate material of the LTCC substrate 2 is a material obtained by kneading a binder or a solvent with raw material powder containing an alumina component and a glass component, and forming this into a sheet using a doctor blade molding machine. The distribution ratio of the alumina component and the glass component is 5 to 5. The conductor 5 is formed by printing or punching Ag paste on the green sheet 4, and then loaded into a firing furnace in a state where a plurality of the green sheets 4 are stacked on the firing setter 1. The LTCC substrate 2 is manufactured by baking at a temperature of 870C to 870C.

  The firing setter 1 is obtained by laminating and firing a plurality of green sheets containing an alumina component and a glass component, and the distribution ratio of the alumina component and the glass component in the green sheet is in the range of 9: 1 to 8: 2, that is, The compounding ratio of the glass component to the alumina component is set in the range of 10 to 20%. In this way, the firing setter 1 is configured by firing the same green sheet as the LTCC substrate 2, but the mixing ratio of the glass components in the green sheet is considerably smaller than the green sheet 4 of the LTCC substrate 2. Is set to

  When the green sheet 4 is placed on the firing setter 1 and fired, the green sheet 4 moves in the direction of the arrow in FIG. Here, as shown in FIG. 2, when the conductors 5a, 5b, and 5c are formed at the positions indicated by the solid lines of the green sheet 2 before firing, the green sheet 2 after firing is indicated by a broken line toward the center O. As shown, the conductors 5a, 5b, and 5c move toward the center O to the positions indicated by broken lines. In FIG. 2, the Ag via is exemplified as the conductor 5 (5a, 5b, 5c), but the other conductor 5 such as a wiring pattern or a land contracts similarly. And in anticipation of the movement trajectory before and after the contraction of these conductors 5 (5a, 5b, 5c), a plurality of convex portions 3 are formed at positions avoiding the conductor trajectory on the firing setter 1, specifically, The convex portions 3 are not formed on the line where the conductors 5a, 5b, and 5c move from the solid line position to the broken line position in FIG. 2 before and after contraction, and a plurality of convex portions 3 are arranged in a balanced manner in other regions. .

  Next, a manufacturing method of the LTCC substrate 2 (ceramic multilayer substrate) according to this embodiment will be described with reference to FIGS.

  First, as shown in step S-1 of FIG. 3, when the green sheet 4 that is the substrate material of the LTCC substrate 2 is baked, the locus on which the conductor 5 on the outer surface moves as the shrinkage is confirmed (trajectory confirmation step). ). In this trajectory confirmation step, for example, the conductor positions before and after contraction are displayed on the same CAD screen, and the confirmation data of the trajectory is obtained by connecting the conductor arrangement before and after contraction with a straight line.

  Next, as shown in step S-2 of FIG. 3, based on the CAD data acquired in step S-1, a firing setter 1 having a plurality of convex portions 3 provided on the surface is prepared (setter processing step). ). In this setter processing step, as shown in FIG. 4A, the formation position, shape (circular, square, triangular, etc.) or size of the convex portion 3 is adjusted to the contraction trajectory of the conductor 5 based on CAD data. The processing data set optimally is created, and using this processing data, the resin film 6 having an opening corresponding to the convex portion 3 and the metal plate 7 having an opening corresponding to the convex portion 3 are formed. Make each. Here, the resin film 6 is made of a material having excellent releasability such as PET, PP, and PE, and the metal plate 7 is made of a material having excellent corrosion resistance such as SUS. Drill, laser, etching, etc. are used as appropriate.

  Then, a PET film 9 for mold release is overlaid on the lower smooth plate 8 made of SUS or the like, and a predetermined number of the above-mentioned green sheets 10 that are the base material of the firing setter 1 are overlaid thereon. The resin film 6 and the metal plate 7 are sequentially stacked on the sheet 10. Finally, with the upper smooth plate 12 made of SUS or the like overlaid on the metal plate 7 with the PET film 11 for release, the upper smooth plate 12 is replaced with the lower smooth plate as shown in FIG. When a pressure is applied toward the side 8 at a predetermined pressure (for example, 50 MPa), as shown in FIG. 4C, a part of the green sheet 10 is displaced into the opening of the metal plate 7 and the resin film. Thereafter, as shown in FIG. 4 (d), the upper and lower smooth plates 8 and 12 and the PET films 9 and 11 are released to produce a sheet 13 with a convex portion. By baking at 900 degreeC, the above-mentioned baking setter 1 in which the some convex part 3 was provided in the surface is produced. The resin film 6 and the upper and lower PET films 9 and 11 can be omitted if the metal plate 7, the lower smooth plate 8 and the upper smooth plate 12 are attached by means such as applying a release agent. .

  After producing the firing setter 1 in the setter processing step in this manner, as shown in step S-3 of FIG. 3, the green sheet 4 that is the substrate material of the LTCC substrate 2 is placed on the firing setter 1 and fired. (Substrate firing step). In this substrate firing step, a plurality of green sheets 4 are stacked on the contact surface of the firing setter 1 provided with the convex portions 3, and the LTCC substrate 2 is manufactured by firing at about 830 ° C. to 870 ° C. in this state. Is done. At that time, the conductor 5 exposed on the outer surface of the green sheet 4 changes in position with shrinkage during firing, but the convex portions 3 of the firing setter 1 are arranged at positions that do not interfere with the movement locus of the conductor 5. The conductor 5 moves in the shrinking direction without coming into contact with the convex portion 3 of the firing setter 1. Accordingly, the contact area between the green sheet 4 and the firing setter 1 can be reduced by the convex portion 3, and the scratches on the conductor 5 generated during firing and the deformation of the conductor due to the rubbing can be reduced. Thus, the LTCC substrate 2 having a good yield can be manufactured.

  As described above, the firing setter 1 according to the present embodiment has the plurality of convex portions 3 on the contact surface with the LTCC substrate 2, so that the green sheet 4 that is the substrate material of the LTCC substrate 2 at the time of firing. Can be prevented from being melt-bonded to the contact surface of the firing setter 1, and even if the conductor 5 exposed on the outer surface of the green sheet 4 fluctuates due to shrinkage during firing, the convexity of the firing setter 1 can be prevented. Since the portions 3 are arranged at positions where they do not interfere with the movement locus of the conductor 5, it is possible to reduce or completely eliminate the scratches on the conductor 5 that occur during firing and the deformation of the conductor due to rubbing.

  Moreover, in the firing setter 1 according to this embodiment, the base material of the firing setter 1 is configured using the same green sheet as the LTCC substrate 2, and the blending ratio of the glass component to the alumina component of the green sheet 10 is 10 to 10. Since it is set in the range of 20%, it becomes possible to produce the firing setter 1 at a low cost, and the blending ratio of the glass components of the firing setter 1 is set to be considerably lower than that of the LTCC substrate 2. The glass components on the LTCC substrate 2 side and the firing setter 1 side can be prevented from melting and adhering during firing.

  Moreover, the manufacturing method of the LTCC board | substrate 2 which concerns on this example embodiment acquires the movement locus | trajectory before and after the conductor 5 of the outer surface of the green sheet 4 shrink | contracts with baking as confirmation data beforehand, and is based on this data Since the firing setter 1 provided with a plurality of projections 3 is prepared, when the green sheet 4 is actually fired using the firing setter 1, the conductor 5 contacts the projections 3 of the firing setter 1. It moves in the contraction direction without doing. Accordingly, the contact area between the green sheet 4 and the firing setter 1 can be reduced by the convex portion 3, and the scratches on the conductor 4 generated during firing and the deformation of the conductor due to the rubbing can be reduced or completely eliminated. Thus, the LTCC substrate 2 having a good yield can be manufactured by reducing the scratch defects.

  And in the manufacturing method of the LTCC board | substrate 2 which concerns on this example of an embodiment, the setter processing process which processes the baking setter 1 produces the metal plate 7 in which the opening corresponding to the convex part 3 was pierced, and this metal. A step of producing a sheet 13 having a convex portion by displacing a part of the green sheet 10 into the opening of the metal plate 7 by pressurizing the plate 7 and the plurality of green sheets 10, and the convex portion. And the step of producing the fired setter 1 by firing the attached sheet 13, the fired setter 1 can be produced easily and inexpensively.

  In the above embodiment, the LTCC substrate 2 is exemplified as the ceramic multilayer substrate. However, the firing setter and the method for manufacturing the ceramic multilayer substrate according to the present invention are applied to an HTCC (High Temperature Co-fired Ceramics) substrate. Is also possible.

1 Firing setter 2 LTCC substrate (ceramic laminated substrate)
DESCRIPTION OF SYMBOLS 3 Convex part 4 Green sheet 5, 5a, 5b, 5c Conductor 6 Resin film 7 Metal plate 8 Lower smooth plate 9,11 PET film 10 Green sheet 12 Upper smooth plate 13 Sheet with convex part

Claims (4)

In a firing setter that performs firing treatment of the ceramic multilayer substrate in a state where the ceramic multilayer substrate having a conductor formed on the outer surface is placed,
A plurality of convex portions are provided on the contact surface with the ceramic multilayer substrate, and the convex portions are arranged at positions that do not interfere with the movement trajectory of the conductor accompanying shrinkage during firing of the ceramic multilayer substrate. Characteristic firing setter.   2. The ceramic laminated substrate according to claim 1, wherein the ceramic laminated substrate is an LTCC substrate, the base material of the fired setter is made of a material containing an alumina component and a glass component, and the blending ratio of the glass component is 10 to 20%. A firing setter characterized by being set in a range of. A locus confirmation step for confirming a locus where the conductor on the outer surface moves with contraction when firing the green sheet,
A setter processing step of processing a firing setter provided with a plurality of convex portions on the surface based on the data obtained in the locus confirmation step;
A substrate firing step for firing the ceramic laminated substrate in a state where a green sheet is placed on the firing setter obtained in the setter processing step;
The ceramic laminated substrate is characterized in that the arrangement pattern of the convex portions provided on the firing setter is set at a position that does not interfere with the locus of the conductor that moves with contraction in the substrate firing step. Manufacturing method.   4. The method according to claim 3, wherein the setter processing step includes a step of producing a metal plate in which an opening corresponding to the convex portion is formed, and pressurizing in a state where the metal plate and a plurality of green sheets are laminated. A step of displacing a part of the green sheet into the opening of the metal plate to produce a sheet with convex portions, and a step of firing the sheet with convex portions to produce the fired setter. A method for manufacturing a ceramic laminated substrate.