JP5290267B2 - Ceramic substrate firing buffer sheet and method for producing ceramic substrate using the same - Google Patents

Description

  The present invention relates to a ceramic substrate firing buffer sheet and a method for producing a ceramic substrate using the same, and more specifically, a ceramic substrate firing buffer capable of preventing warpage of the ceramic substrate that occurs during the firing process. The present invention relates to a sheet and a method of manufacturing a ceramic substrate using the sheet.

  Generally, ceramic substrates, especially low temperature co-fired ceramic (LTCC) substrates, have excellent electrical characteristics such as thermal characteristics and dielectric constant, and can be miniaturized and have multiple functions. It can be used and is used in various technical fields.

  Further, the low-temperature co-fired ceramic substrate can be subjected to non-shrinkage firing in the surface direction by using a constraining layer, and its application has been expanded to a substrate for semiconductor inspection or the like that requires circuit pattern accuracy. In particular, the semiconductor inspection substrate has a large area and is manufactured to be thick enough to withstand repeated pressure during inspection. Therefore, there is a demand for a method capable of firing a large area substrate without warping while having excellent flatness.

  The firing process of the ceramic substrate is generally a process of firing a formed body on which green sheets are laminated in a firing furnace. During firing, the green sheet formed body is placed on a firing setter to support the structure. . However, local firing stress is generated in the green sheet molded body due to the frictional force and reactivity generated at the contact portion between the green sheet molded body and the fired setter during the firing process, and thus a large number of warps such as warpage of the ceramic substrate after firing. Defects occur.

In particular, as described above, since the ceramic substrate has recently been increased in area and its thickness tends to gradually increase, the above problem has become more serious.

Korean Patent No. 2009-0061904 Korean Patent No. 2009-0046600 JP 2005-263597 A

  The present invention is for solving the above-described problems, and an object of the present invention is to provide a ceramic substrate firing buffer sheet capable of preventing warpage of the ceramic substrate during the firing process, and a ceramic substrate using the ceramic substrate. It is to provide a manufacturing method.

  One embodiment of the present invention is a buffer sheet having a first surface on which a ceramic substrate is stacked and a second surface opposite to the first surface, the buffer sheet having a plate-shaped first powder and a spherical shape. The first surface includes a second powder, and the first surface provides a firing buffer sheet for a ceramic substrate having a higher distribution ratio of the first powder than the second powder.

The first powder and the second powder may be hardly sinterable powders that are not sintered at the sintering temperature of the ceramic substrate.
The first powder and the second powder may have different materials or densities.

More than 80% of the first powder may be distributed over a certain range of thickness from the first surface of the buffer sheet. The thickness of the fixed range can 10% to 80% of the thickness range near Rukoto of the thickness of the buffer sheet relative to the first surface.

  The plate-shaped first powder may have a width of 5 μm to 20 μm and a thickness of 0.1 μm to 1.0 μm.

  The average particle size of the spherical second powder may be 1 μm to 3 μm.

  The buffer sheet may have a thickness of 3 μm to 300 μm.

  According to another embodiment of the present invention, a slurry including a plate-shaped first powder and a spherical second powder is produced, and a shear stress is applied to the slurry, and the plate-shaped first powder is placed on the top. And a step of forming the buffer sheet so that the spherical second powder is disposed underneath, and a method for producing a buffer sheet for firing a ceramic substrate.

  The first powder and the second powder may have different materials or densities.

  Still another embodiment of the present invention has a first surface on which a ceramic substrate is loaded and a second surface opposite to the first surface, and includes a plate-shaped first powder and a spherical second powder. The first surface is loaded with a firing buffer sheet having a higher distribution ratio of the first powder than the second powder on the firing setter so that the second surface is in contact with the second surface; There is provided a method for manufacturing a ceramic substrate, comprising: loading a ceramic green sheet on a first surface; and firing the ceramic green sheet.

  The first powder and the second powder may be hardly sinterable powders that are not sintered at the sintering temperature of the ceramic substrate.

  The first powder and the second powder may have different materials or densities.

More than 80% of the first powder is distributed over a constant thickness from the first surface of the buffer sheet can Rukoto. The certain range of thicknesses may be in a range of 10% to 80% of the thickness of the buffer sheet based on the first surface .

  The plate-shaped first powder may have a width of 5 μm to 20 μm and a thickness of 0.1 μm to 1.0 μm.

  The average particle size of the spherical second powder may be 1 μm to 3 μm.

  The firing buffer sheet may have a thickness of 3 μm to 300 μm.

  In the first surface of the firing buffer sheet according to an embodiment of the present invention, a plate-shaped first powder having a wide gap between powder particles is mainly located, and there are few contact points with the ceramic green sheet. Therefore, when the ceramic green sheet is fired, the capillary force for diffusing the glass component from the ceramic substrate becomes insufficient, and the reaction between the ceramic substrate and the firing buffer sheet can be effectively suppressed. Thereby, reaction of a ceramic substrate and a firing setter can be prevented regardless of the weight of the ceramic substrate.

  In addition, the spherical second powder is disposed on the second surface of the firing buffer sheet to ensure a debinding path.

It is a schematic sectional drawing which shows the manufacturing method of the ceramic substrate by one Embodiment of this invention. It is sectional drawing which shows roughly the buffer sheet for baking by one Embodiment of this invention. FIG. 3 is a perspective view schematically showing a plate-like first powder and a spherical second powder according to an embodiment of the present invention. FIG. 3 is a perspective view schematically showing a plate-like first powder and a spherical second powder according to an embodiment of the present invention. It is sectional drawing which shows schematically the manufacturing method of the buffer sheet for baking by one Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  However, the embodiments of the present invention can be modified in various other forms, and the scope of the present invention is not limited to only the embodiments described below. In addition, the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. Accordingly, the shapes and sizes of the components in the drawings may be exaggerated for a clearer description, and the components indicated by the same reference numerals in the drawings are the same components.

  FIG. 1 is a schematic cross-sectional view illustrating a method of manufacturing a ceramic substrate according to an embodiment of the present invention.

  Referring to FIG. 1, a method of manufacturing a ceramic substrate according to an embodiment of the present invention includes a step of stacking a firing buffer sheet 10 on a firing setter S, and a step of placing a ceramic green sheet on the firing buffer sheet 10. And firing the ceramic green sheet.

  The firing buffer sheet 10 is a buffer sheet having a first surface on which a ceramic substrate is stacked and a second surface facing the first surface, and the ceramic substrate is stacked on the first surface. The second surface is placed in contact with the firing setter. The buffer sheet includes a plate-shaped first powder and a spherical second powder, and the first surface is characterized by a higher ratio of the first powder to the second powder than the second surface. Specific matters for this will be described later.

  The ceramic substrate is generally produced by producing a ceramic green sheet and then firing the ceramic green sheet. The firing process of the ceramic green sheet can be generally performed in a firing furnace, and during firing, the ceramic green sheet can be placed on a firing setter to support the structure.

  The ceramic substrate C may be a low temperature co-fired ceramic substrate. Low temperature co-fired ceramic substrate is manufactured by producing dielectric sheet, forming via sheet formation and peeling process of dielectric, conductive pattern printing process, lamination process, forming green sheet laminate, and firing the green sheet laminate Can be done.

  According to the present embodiment, the firing buffer sheet 10 is stacked between the firing setter S and the ceramic green sheet C.

  Generally, in the firing process of the ceramic green sheet, the glass component contained in the ceramic green sheet is eluted to the outside and can react with the fired setter. As a result, the sintering shrinkage is partially disturbed at the reaction site between the ceramic green sheet and the firing setter, causing a variation in the shrinking behavior of the ceramic substrate, which may warp the ceramic substrate after firing.

  However, according to the present embodiment, the firing buffer sheet 10 serves to prevent a reaction between the firing setter S and the ceramic green sheet C in the firing process.

  In the first surface of the firing buffer sheet according to an embodiment of the present invention, a plate-shaped first powder having a wide gap between powder particles is mainly located, and there are few contact points with the ceramic green sheet. Therefore, if the ceramic green sheet is fired while being in contact with the first surface, the capillary force for diffusing the glass component from the ceramic substrate is insufficient, so that the reaction between the ceramic substrate and the firing buffer sheet is effectively performed. Can be suppressed. Thereby, reaction of a ceramic substrate and a firing setter can be prevented regardless of the weight of the ceramic substrate. In addition, the reaction between the ceramic substrate and the firing buffer sheet can be effectively suppressed.

  Further, the spherical second powder is disposed at the lower part of the firing buffer sheet to secure a debinding path.

  FIG. 2 is a cross-sectional view schematically showing a firing buffer sheet 10 according to an embodiment of the present invention.

  Referring to FIG. 2, the firing buffer sheet 10 has a first surface 10a and a second surface 10b facing the first surface. The first surface 10a is a surface on which a ceramic substrate is loaded, and the second surface 10b is a surface in contact with the firing setter.

  The firing buffer sheet 10 according to the present embodiment includes a plate-shaped first powder 11 and a spherical second powder 12. The first and second powders may be hardly sinterable powders that are not sintered at the firing temperature of the ceramic green sheet.

  The first surface 10a is mainly arranged with a plate-shaped first powder 11 from the spherical second powder 12, and the second surface 10b is arranged with the second powder 12 having a spherical shape from the plate-shaped first powder 11. The first surface 10a may have a higher distribution ratio of the first powder 11 than the second powder 12 compared to the second surface 10b. Such an arrangement can be formed during the manufacturing process of the firing buffer sheet.

  3a and 3b are perspective views schematically showing a plate-shaped first powder 11 and a spherical second powder 12 according to an embodiment of the present invention.

  Referring to FIGS. 3a and 3b, in the first powder 11 having the plate shape, a width w which is a horizontal size is 5 μm to 20 μm, and a thickness t which is a vertical size is 0.1 μm to It can be 1.0 μm.

  The plate-shaped first powders 11 are horizontally arranged in the firing buffer sheet 10, have a wide gap with the particles, and reduce the contact point with the ceramic substrate. Therefore, the glass component penetrates from the ceramic substrate to the buffer sheet side, and the capillary force for forming the bond becomes insufficient, and the reaction between the ceramic substrate and the firing buffer sheet can be prevented.

  The plate-shaped first powder 11 is not limited thereto, but may be made of an alumina or zirconia material that can be easily manufactured into a plate-like shape.

  The spherical second powder 12 may have an average particle diameter d of 1 μm to 3 μm.

  The spherical second powder 12 may be made of alumina or zirconia, but is not limited thereto.

  The spherical second powder 12 is mainly arranged on the second surface of the firing buffer sheet, and the gap between the second powder particles can act as a debinding path in the firing process of the ceramic green sheet. Thereby, the shortage of the debinding path due to the plate-shaped first powder can be solved, the thickness of the buffer sheet for firing can be increased, and the weight or thickness of the ceramic substrate to be fired can be increased. Even if the thickness increases, the ceramic substrate can be fired without being deformed.

Many of the plate-shaped first powders 11 may be distributed on the first surface of the buffer sheet. More specifically, the first 80% of the powder are distributed over a first predetermined thickness from the surface of the buffer sheet can Rukoto. The thickness of the certain range is in the range of thickness of 10% to 80% of the thickness of the buffer sheet relative to the first surface. Since the plate-shaped first powder covers the surface of the buffer sheet and the distribution range of the plate-shaped first powder becomes wide, the debinding path may be blocked and debinding may not be performed reliably. It is preferable to exist within a certain range of thickness.

  The first powder and the second powder may use different substances or have different densities in order to more stably classify the arrangement positions of the first powder and the second powder in the process of manufacturing the buffer sheet for firing. Different substances can be used. For example, when the firing buffer sheet is manufactured so that the second surface is located at the lower part, the second powder that precipitates at the lower part of the firing buffer sheet uses a substance having a higher density than the first powder. Can do.

  The thickness of the firing buffer sheet 10 may be 3 μm to 300 μm. When the thickness of the firing buffer sheet exceeds 300 μm, the debinding property is lowered due to the weight of the ceramic substrate, while when the thickness of the firing buffer sheet is less than 3 μm, the reaction between the ceramic substrate and the firing setter. May not be sufficiently suppressed.

  FIG. 4 is a cross-sectional view schematically showing a method for producing a firing buffer sheet according to an embodiment of the present invention.

  First, the plate-like first powder and the spherical second powder are mixed with a binder, a dispersant, a solvent, and the like to produce a slurry 10A.

  The slurry 10A is applied onto the base film 12 using the blade B, and then dried to produce a firing buffer sheet. As the base film 12, a PET (Polyethylene Terephthalate) film can be used.

  In the process of applying the slurry onto the base film, the plate-shaped first powder is horizontally arranged due to the shear stress and the solvent flow existing between the base film and the blade, and the area receiving buoyancy increases. The second powder, which is less likely to settle downward during the drying process and is mainly located at the upper part of the buffer sheet, is relatively spherical and penetrates and settles relatively freely during the drying process of the slurry. Becomes mainly located. In addition, when the plate-shaped first powder has a higher density than the spherical second powder, the arrangement positions of the first powder and the second powder can be more stably distinguished.

  The upper part of the buffer sheet is a first surface on which the ceramic substrate is stacked, and the lower part of the buffer sheet is a second surface to be joined to the firing setter.

  Table 1 below shows Examples 1 and 2 to which the above-described firing buffer sheet is applied in the firing process of the ceramic substrate according to an embodiment of the present invention, Comparative Examples 1 and 2 to which the firing buffer is not applied, and spherical shapes. It is an experimental result with respect to the comparative examples 3 and 4 to which the buffer sheet for baking containing only powder was applied. The thickness of the firing buffer sheet applied to the above Examples and Comparative Examples was 60 μm. In Examples 1 and 2, the thickness of the layer in which the plate-shaped first powder occupies 80% or more of the thickness of the firing buffer sheet was 10 μm.

  Example 1, Comparative Example 1 and Comparative Example 3 use a 18 cm × 18 cm × 0.5 cm (horizontal × vertical × thickness) ceramic substrate, and Example 2, Comparative Example 2 and Comparative Example 4 are 25 cm × A ceramic substrate having a size of 25 cm × 0.5 cm (width × length × thickness) was used.

The camber measured the warp of the entire ceramic substrate after firing, and the amount of residual carbon was measured by cutting it into 1 × 1 cm ² (horizontal × vertical).

  Referring to Table 1 above, Comparative Example 1 and Comparative Example 2 had a small amount of residual carbon because the debinding path was insufficient, but due to the reaction between the ceramic substrate and the firing setter due to the non-use of the firing buffer sheet, Deformation occurred and the camber of the ceramic substrate was very large. In Comparative Example 3, the reaction between the ceramic substrate and the firing setter was suppressed by the firing buffer sheet, and the camber was small. In Comparative Example 4, the camber was greatly increased while the weight of the ceramic substrate was increased. This is a result of the heavy ceramic substrates being bonded while pressing the firing buffer sheet, and the firing buffer sheet acting like a constraining layer in the non-shrink firing process. That is, the camber is increased by firing with an asymmetric structure in which a constraining layer is bonded to only one surface of the ceramic substrate. On the other hand, Example 1 and Example 2 show the result that the plate-shaped powder effectively suppresses the reaction between the ceramic substrate and the firing setter, and also improves the camber, and the residual carbon is due to the presence of the spherical powder. The increase in quantity was also suppressed.

  The present invention is not limited by the above-described embodiments and attached drawings, but is limited by the appended claims. Accordingly, it is obvious to those skilled in the art that various forms of substitution, modification, and change are possible without departing from the technical idea of the present invention described in the claims. Yes, this also belongs to the technical matters described in the claims.

DESCRIPTION OF SYMBOLS 10 Baking buffer sheet 11 Plate-shaped first powder 12 Spherical second powder C Ceramic substrate S Firing setter

Claims (9)

Producing a slurry comprising a plate-shaped first powder and a spherical second powder;
Applying shear stress to the slurry, and molding the buffer sheet so that the plate-shaped first powder is disposed at the top and the spherical second powder is disposed at the bottom;
A method for producing a buffer sheet for firing ceramic substrates. The method for manufacturing a buffer sheet for firing a ceramic substrate according to claim 1 , wherein the first powder and the second powder have different materials or densities. The ceramic substrate includes a first surface on which a ceramic substrate is loaded and a second surface opposite to the first surface, and includes a plate-shaped first powder and a spherical second powder, and the first surface includes the second surface. Providing a firing buffer sheet having a higher distribution ratio of the first powder than the second powder compared to the surface;
Loading the firing setter so that the second surface is in contact;
Loading ceramic green sheets on the first surface;
Firing the ceramic green sheet,
Providing the firing buffer sheet comprises producing a slurry containing the plate-like first powder and the spherical second powder;
Applying shear stress to the slurry, and molding the buffer sheet so that the plate-shaped first powder is disposed at the top and the spherical second powder is disposed at the bottom;
A method for manufacturing a ceramic substrate comprising: The method for producing a ceramic substrate according to claim 3 , wherein the first powder and the second powder are hardly sinterable powders that are not sintered at the sintering temperature of the ceramic substrate. The method for manufacturing a ceramic substrate according to claim 3 , wherein the first powder and the second powder have different materials or densities. 80% or more of the first powder is distributed over a certain range of thickness from the first surface of the buffer sheet,
4. The method of manufacturing a ceramic substrate according to claim 3 , wherein the certain range of thickness is in the range of 10% to 80% of the thickness of the buffer sheet based on the first surface. 5. Method. 4. The method of manufacturing a ceramic substrate according to claim 3 , wherein the first powder having a plate shape has a width of 5 μm to 20 μm and a thickness of 0.1 μm to 1.0 μm. 4. The method of manufacturing a ceramic substrate according to claim 3 , wherein the spherical second powder has an average particle size of 1 μm to 3 μm. The method for producing a ceramic substrate according to claim 3 , wherein the firing buffer sheet has a thickness of 3 µm to 300 µm.

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