WO2011152544A1

WO2011152544A1 - Ceramic substrate and method for manufacturing same

Info

Publication number: WO2011152544A1
Application number: PCT/JP2011/062861
Authority: WO
Inventors: 雄治後藤; 太治黒岩
Original assignee: パナソニック株式会社
Priority date: 2010-05-31
Filing date: 2011-05-30
Publication date: 2011-12-08
Also published as: JP2013165086A

Abstract

Disclosed is a ceramic substrate having a ceramic substrate section, which is formed by firing a laminated body of a plurality of green sheets, and a chip-type electronic component, which is disposed inside of the ceramic substrate section. Furthermore, the ceramic substrate has a gap filling material, which is formed in a fillet shape in a peripheral region of an electrode section of the chip-type electronic component.

Description

Ceramic substrate and manufacturing method thereof

The present invention relates to a ceramic substrate and a manufacturing method thereof. More specifically, the present invention relates to a ceramic substrate made of a laminated fired body of green sheets, and also relates to a method for manufacturing such a ceramic substrate.

The ceramic substrate is excellent in heat resistance and moisture resistance, and may have good frequency characteristics in a high frequency circuit. Accordingly, the ceramic substrate is used as an RF (Radio Frequency) module of a mobile device, a substrate for a power LED (Light Emitting Diode) utilizing heat dissipation, and a substrate for an LED for a liquid crystal backlight. It is also used as a substrate for electronic equipment on which electronic components are mounted with high density.

The ceramic substrate is obtained by laminating and firing a plurality of green sheets. The ceramic substrate is provided with vias and circuit patterns. In recent years, in order to further reduce the size of LEDs for liquid crystal backlights, it has been required to incorporate chip-type electronic components inside a ceramic substrate (see, for example, International Publication No. 2006/030562). .

Due to the above background, attempts have been made to incorporate chip-type electronic components in the ceramic substrate, but the inventors of the present application have a specific phenomenon when the ceramic substrate is obtained from the green sheet laminate by incorporating the chip-type electronic components. Found out that it would occur. Specifically, as shown in FIGS. 18 (a) to 18 (c), it has been found that a gap is generated in the vicinity of the electrode of the chip-type electronic component, resulting in poor electrical connection.

Such poor electrical connection can reduce the inherent performance of the ceramic substrate, resulting in a decrease in the production yield of the ceramic substrate.

The present invention has been made in view of such circumstances. That is, the main object of the present invention is to prevent electrical connection failure of a ceramic substrate incorporating a chip-type electronic component, and to improve the manufacturing yield.

In order to solve the above problems, in the present invention,
Comprising a ceramic substrate portion formed by firing a laminate of a plurality of green sheets, and a chip-type electronic component disposed inside the ceramic substrate portion,
In the peripheral region of the electrode part of the chip-type electronic component, a ceramic substrate further provided with a gap filling material formed in a fillet shape is provided.

One feature of the ceramic substrate according to the present invention is that a fillet-like gap filler is provided in the peripheral region of the electrode part of the chip-type electronic component.

The term “fillet” is used in the soldering industry and is used herein in view of the meaning used in the technical field of such solder. That is, “fillet” in the present specification means that the gap filler has a shape corresponding to the solder pile shape or a shape similar thereto. As a specific example, as defined in page 1825 of JIS Industrial Glossary Dictionary 5th edition (editor and publisher: Japanese Standards Association) “Fillet” may be understood as meaning “the shape of the resulting solder pile” or a shape similar thereto.

The fillet-like gap filler disposed inside the ceramic substrate portion has a gradually decreasing thickness. In particular, in the ceramic substrate of the present invention, the thickness of the gap filler gradually decreases along the direction from the chip-type electronic component toward the outside (that is, toward the outer side in the horizontal direction from the chip-type electronic component as a base point). The thickness of the gap filler gradually decreases).

In a preferred aspect, the gap filler is in partial contact with the electrode part of the chip-type electronic component. That is, the fillet-like gap filler and the electrode part of the chip-type electronic component are in contact with each other.

In another preferred aspect, the ceramic substrate portion further includes an internal wiring portion, and the gap filler is in partial contact with the internal wiring portion. That is, the fillet-like gap filler and the internal wiring part of the ceramic substrate are in contact with each other.

In still another preferred embodiment, the ratio of the maximum width dimension Wmax to the maximum thickness dimension Tmax (Wmax / Tmax) is about 3 to 15 with respect to the dimension ratio of the gap filler.

When the chip-type electronic component has two opposing electrode portions, it is preferable that a gap filler is provided in a fillet shape in the peripheral region of each of the two electrode portions.

The gap filler for the ceramic substrate of the present invention preferably comprises at least one of the following components:
-Silver component-Palladium component-Same component as inorganic component contained in green sheet-Copper component

The present invention also provides a method for manufacturing the above-described ceramic substrate. Such a production method of the present invention comprises:
(I) For two green sheets selected from a plurality of green sheets, a first gap filler material is applied to one green sheet to form a first gap filler precursor, and Applying a two-gap filler material to form a second gap-filler precursor;
(Ii) A step of forming a green sheet laminate by laminating a plurality of green sheets, and in laminating the one green sheet and the other green sheet, the first gap filler precursor and the second gap A step of sandwiching a chip-type electronic component between the one green sheet and the other green sheet with the filler precursor facing each other; and (iii) firing the green sheet laminate And a step of obtaining a ceramic substrate portion,
When the chip-type electronic component is sandwiched, the first gap filler precursor and the second gap filler precursor are aligned with each other in the peripheral region of the electrode portion of the chip-type electronic component, and the gap filling is performed by integrating them. When the green sheet laminate is fired, the green sheet laminate is pressed in the thickness direction from the outside to the inside. It is formed from a “material precursor”.

One of the features of the method for producing a ceramic substrate according to the present invention is that the first gap filler precursor and the second gap filler precursor are disposed in the peripheral region of the electrode portion of the chip type electronic component when the chip type electronic component is sandwiched. To form a gap filler precursor that integrates them, and presses the laminate in the thickness direction from the outside to the inside during firing of the green sheet laminate to fillet-like gap filler Is formed from “integrated gap filler precursor”.

While sandwiching the chip-type electronic component, “one green sheet coated with the first gap filler material” is arranged vertically upward (vertically upper side), while “the other green sheet coated with the second gap filler material” "Is disposed vertically downward (vertically below), it is preferable that the coating amount of the second gap filler material is larger than the coating amount of the first gap filler material. Thereby, a fillet-like gap filler can be suitably formed.

Further, when a chip-type electronic component having two opposing electrode portions is incorporated, when the chip-type electronic component is sandwiched, the first gap filler precursor and the second gap in each peripheral region of the two electrode portions It is preferable to integrate the filler precursor with each other.

In a preferred embodiment, when the two electrode portions are viewed along a direction in which they face each other, the inner end portion of the coating film of the second gap filler precursor is about 0.2 mm to about 0.2 mm from the center portion of the chip-type electronic component. The chip-type electronic component is sandwiched in a state where the positional relationship is maintained such that the position is about 0.5 mm away.

In another preferred embodiment, the thickness dimension of the coating film of the second gap filler precursor is about 60 μm to about 150 μm.

In still another preferred embodiment, a constraining layer is provided on the outer surface of the green sheet laminate (especially on two opposing outer main surfaces), and the thickness of the green sheet laminate is measured from the outside to the inside through the constraining layer. Press in the direction.

According to the present invention, when a ceramic substrate is obtained from a green sheet laminate with a built-in chip-type electronic component, “a void that can occur in the vicinity of the electrode of the chip-type electronic component” is preferably avoided.

More specifically, in the ceramic substrate of the present invention, due to the fact that the fillet-like gap filler is provided, all the gaps in the vicinity of the electrodes of the built-in chip type electronic component are filled, As a result, the substrate has no internal void.

In other words, in the present invention, since a gap in the vicinity of the electrode of the chip-type electronic component is avoided, an electrical connection failure caused by the gap (particularly an electrical connection between the chip-type electronic component and the internal wiring portion). Defective), and thus the production yield of the ceramic substrate can be improved.

Furthermore, since the fillet-like gap filling material can be formed from a material having high thermal conductivity, the present invention is effective for the heat dissipation characteristics of the substrate. For example, when it is required to take measures against heat dissipation for an LED package substrate or a module substrate, in the present invention, a “fillet-like gap filler” that effectively contributes to heat dissipation is provided without increasing the substrate volume. Therefore, a relatively thin small ceramic substrate having excellent heat dissipation characteristics can be realized.

1 (FIG. 1) is a cross-sectional view schematically showing an embodiment of the ceramic substrate of the present invention.
FIG. 2 (FIG. 2) is a transparent perspective view schematically showing an aspect of the ceramic substrate of the present invention.
3 (FIG. 3) is a diagram for explaining the “peripheral region of the electrode part” (FIG. 3A) and a diagram for explaining the dimensional ratio (Wmax / Tmax) of the gap filler (FIG. FIG. 3B).
(A) to (d) in FIG. 4 (FIG. 4) are cross-sectional views schematically showing various forms of the fillet-like gap filler.
5A is a cross-sectional view schematically showing an embodiment of the ceramic substrate of the present invention, and FIG. 5B is a cross-sectional view taken along the line aa ′ in FIG. It is sectional drawing of a board | substrate.
6 (FIG. 6) shows a process flow of the manufacturing method of the present invention.
Fig. 7 (Fig. 7) is a cross-sectional view schematically showing the steps in the ceramic substrate manufacturing process of the present invention.
Fig. 8 (Fig. 8) is a plan view schematically showing an aspect of the first gap filler precursor and the second gap filler precursor.
9 (a) and 9 (b) are cross-sectional views schematically showing the steps in the ceramic substrate manufacturing process of the present invention.
10 (a) and 10 (b) are cross-sectional views schematically showing the steps in the ceramic substrate manufacturing process of the present invention.
11 (FIG. 11) is a cross-sectional view schematically showing the steps in the ceramic substrate manufacturing process of the present invention.
12 (a) and 12 (b) are cross-sectional views schematically showing steps in the ceramic substrate manufacturing process of the present invention.
FIG. 13 (FIG. 13) is a view for explaining a preferred embodiment of the second gap filler precursor.
FIG. 14 (FIG. 14) is a schematic diagram showing a test sample configuration in the example.
Fig. 15 (Fig. 15) is a graph showing the results of the "moisture absorption reflow test", "high temperature storage test", and "heat cycle test" in the examples.
FIG. 16 (FIG. 16) is a diagram showing an aspect and a result of a “confirmation test regarding the arrangement effect of the gap filler precursor”.
FIG. 17 (FIG. 17) is a diagram showing an aspect and a result of a “confirmation test regarding the thickness effect of the gap filler precursor”.
18 (Fig. 18) (a) to (c) are photographic diagrams showing the phenomenon found by the present inventors.

In the drawings, reference numbers refer to the following elements:
DESCRIPTION OF SYMBOLS 10

Ceramic substrate part

10A, 10B, 10C Green sheet 16 Via 17 Internal wiring part (internal wiring layer)
16 ′ via precursor 17 ′ precursor of internal wiring portion 19 external electrode portion (external wiring layer)
20 Electronic circuit pattern wiring part (electronic circuit pattern wiring layer)
40 Chip-type electronic component 42 (42A, 42B) Electrode portion of chip-type electronic component 50 (50A, 50B) Gap filling material (gap filling portion)
51A, 51B First

gap filler precursor

52A, 52B Second gap filler precursor 60 Constrained layer 100 Ceramic substrate

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, components having substantially the same function are denoted by the same reference numerals for the sake of simplicity. Further, the dimensional relationship (length, width, thickness, etc.) in each figure does not reflect the actual dimensional relationship. Further, the “vertical direction” described in this specification corresponds to a direction corresponding to the vertical direction in the drawing for convenience.

(Ceramic substrate of the present invention)
As shown in FIG. 1, a ceramic substrate 100 of the present invention includes a ceramic substrate portion 10 and a chip-type electronic component 40 disposed in the ceramic substrate portion. The ceramic substrate unit 10 is formed by firing a laminate of a plurality of green sheets.

In the ceramic substrate 100 of the present invention, a fillet-like gap filling material 50 is provided in the peripheral region of the chip-type electronic component 40. That is, the gap filler 50 is provided in the form of a fillet around the chip-type electronic component 40. As shown in the drawing, the fillet-like gap filler 50 is provided adjacent to and in the vicinity of the electrode portion 42 of the chip-type electronic component 40 in particular.

As shown in FIG. 1, in the ceramic substrate part 10, in addition to the chip-type electronic component 40 and the gap filling material 50, a via 16 and an internal wiring part 17 are provided. Further, on the front and back surfaces of the ceramic substrate portion 10, an external electrode portion 19 for mounting various electronic components (for example, LEDs) on the ceramic substrate 100 is provided, and an electronic circuit pattern wiring portion 20 is also provided. Yes.

The fillet-like gap filler 50 has a shape corresponding to a solder pile shape as its name suggests. For example, as shown in FIG. 1 and FIG. 2, the fillet-like gap filler 50 has a thickness that gradually decreases in the direction toward the outside from the chip-type electronic component as a base point. Due to the provision of such a fillet-like gap filler, no unnecessary gap is formed inside the ceramic substrate of the present invention. In particular, the gap in the vicinity of the electrode of the chip-type electronic component is preferably filled with a gap filler, and as a result, a substrate form without a gap in which the chip-type electronic component is built is realized. In other words, in the present invention, since the gap filler is “fillet-like”, it can be said that all the gaps near the electrodes of the chip-type electronic component are preferably filled.

The ceramic substrate 100 of the present invention will be described in more detail. The ceramic substrate portion 10 constituting the body of the ceramic substrate may be a ceramic multilayer substrate obtained by laminating and firing a plurality of green sheets. The material and overall dimensions of the ceramic multilayer substrate are not particularly limited as long as they are conventionally used and adopted in the electronic equipment field (for example, a package wiring substrate of a semiconductor integrated circuit LSI). In addition, the materials and overall dimensions of the via 16, the internal wiring part 17, the external electrode part 19, and the electronic circuit pattern wiring part 20 are conventionally used and adopted in the electronic equipment field (for example, a package wiring board of a semiconductor integrated circuit LSI). There is no particular limitation as long as it is.

The chip-type electronic component 40 built in the ceramic substrate is a single electronic component manufactured in a small size. Such a chip-type electronic component 40 includes an electrode portion 42, and particularly includes electrode portions (42A, 42B) at opposite side ends thereof. The thickness dimension of the chip-type electronic component 40 is preferably about 50 to 300 μm, more preferably about 100 to 200 μm. Further, regarding the main surface size of the chip-type electronic component 40, the width L × length W may be about L: 0.4 to 0.6 mm × W: 0.2 to 0.3 mm.

Examples of the chip type electronic component 40 include a varistor element (chip varistor), a chip type resistor, a chip type capacitor, and the like. In particular, one varistor element may be a varistor used in an electronic circuit for driving an LED for a liquid crystal backlight.

In the ceramic substrate 100 according to the present invention, the gap filler 50 provided inside the ceramic substrate portion 10 has a fillet shape. As shown in FIGS. 1 and 2, the fillet-like gap fillers 50 </ b> A and 50 </ b> B are provided in the peripheral regions of the two electrode portions 42 </ b> A and 42 </ b> B facing each other of the chip type electronic component 40. As illustrated, each of the fillet-

like gap fillers

50A and 50B is preferably in partial contact with each of the chip-type electronic components 40A and 40B of the chip-type electronic component 40. More preferably, each gap filler is provided in a fillet shape so as to be at least in contact with the side surface of each chip-type electronic component 40.

Here, the term “peripheral region of the electrode part” used in this specification means an electrode vicinity region adjacent to the electrode part. More specifically, the “peripheral region of the electrode part” is preferably a separation distance from the electrode part (for example, horizontal separation distances L ₁ , L ₂ and L ₃ as shown in FIG. 3A). Indicates a region in the range of about 0.1 to 1.5 mm, more preferably about 0.2 to 1.0 mm.

As shown in FIG. 1 and FIG. 2, the fillet-shaped gap filler 50 gradually decreases in thickness in the direction toward the outside centering on the chip-type electronic component. More specifically, the thickness of the fillet-like gap filler 50 gradually decreases toward the outer side in the horizontal direction parallel to the main surface of the electronic component or the main surface of the substrate, and the thickness is substantially eliminated at the outermost side. That is, the form of the gap filler 50 is not particularly limited as long as it is “fillet-like”, and may be various forms as shown in FIGS. 4 (a) to 4 (d), for example.

As an example of the size of the gap filler 50, the ratio of the maximum width dimension Wmax to the maximum thickness dimension Tmax (Wmax / Tmax) as shown in FIG. 3B is preferably about 3 to 15, more preferably It is about 5-8.

The material of the gap filling material 50 may be the same as the material of the via 16 and the internal wiring part 17, for example. That is, the gap filler 50 may contain a silver component (Ag component), and may be formed from, for example, a silver paste containing silver particles and a glass component. Such a silver paste can be deformed by an external force at the time of heating and pressing during the manufacturing process, and therefore, “a void portion that can occur in the vicinity of an electrode of a chip-type electronic component” can be preferably filled. Further, the silver paste itself can be obtained at a relatively low cost and does not increase the number of materials for manufacturing the substrate, leading to low-cost manufacturing of the ceramic substrate.

Further, the gap filler 50 may contain a palladium component (Pd component). That is, the gap filler 50 may be formed from a conductive paste containing palladium. Since the volume of such a palladium-containing paste increases due to oxidation of palladium during heating and pressing during the manufacturing process, the effect of filling the gap can be improved.

Furthermore, the gap filler 50 may contain the same inorganic component as that of the green sheet. That is, the gap filler 50 may be made of an alumina powder and a glass component. Such a gap filler 50 can be formed from a paste containing the same inorganic components as the green sheet (for example, alumina powder and glass component). In the “paste containing the same inorganic components as the green sheet”, the shrinkage ratio of the green sheet and the shrinkage ratio of the gap filler paste can be made substantially the same during firing in the manufacturing process. Stable firing can be performed. In addition, since the paste itself can be obtained when the green sheet is prepared, the number of materials for manufacturing the substrate is not increased, and as a result, low-cost manufacturing of the ceramic substrate is achieved.

In addition, in order to improve the thermal conductivity of the gap filler 50, the gap filler 50 may additionally contain a copper component. Thereby, the board | substrate excellent in the thermal radiation characteristic especially can be implement | achieved.

(Method for producing a ceramic substrate of the present invention)
Next, the manufacturing method of the ceramic substrate of this invention is demonstrated. As a representative example, a method for manufacturing a ceramic substrate as shown in FIG. 5 will be described. An example of the process flow of the manufacturing method of the present invention is shown in FIG.

First, in manufacturing the ceramic substrate of the present invention, step (i) is performed. That is, the filler precursor raw material is applied to two green sheets selected from a plurality of green sheets. Specifically, as shown in FIGS. 7 and 8, the first gap filler material is applied to one green sheet 10A to form the first gap filler precursor (51A, 51B), and the other green sheet A second gap filler material is applied to the sheet 10B to form second gap filler precursors (52A, 52B).

The green sheet itself may be a sheet-like member including a ceramic component, a glass component, and an organic binder component. For example, the ceramic component may be alumina powder (average particle size: about 0.5 to 10 μm), and the glass component may be borosilicate glass powder (average particle size: about 1 to 20 μm). Good. The organic binder component may be at least one component selected from the group consisting of polyvinyl butyral resin, acrylic resin, vinyl acetate copolymer, polyvinyl alcohol and vinyl chloride resin, for example. The green sheet may be 40 to 50 wt% alumina powder, 30 to 40 wt% glass powder, and 10 to 30 wt% organic binder component (based on the total weight of the green sheet). From another viewpoint, the green sheet is a weight ratio between the solid component (alumina powder 50-60 wt% and glass powder 40-50 wt%: solid component weight basis) and the organic binder component, ie, solid Component weight: Organic binder component weight may be about 80 to 90:10 to 20. The green sheet component may contain other components as required. For example, a plasticizer that imparts flexibility to a green sheet such as phthalate ester or dibutyl phthalate, or a dispersant for ketones such as glycol. Or an organic solvent. The thickness of each green sheet itself may be about 30 μm to 500 μm, for example, about 60 to 350 μm.

Prior to or after the formation of the first and second gap filler precursors, precursors for the vias 16 and the internal wiring portions 17 are formed. For example, a hole is formed in the green sheet by an NC punch press (Numerical Control punch press) or a carbon dioxide laser, and the via precursor 16 ′ is formed by filling the hole with a conductive paste material that is a raw material for the inner layer via. . Also, a fired circuit pattern including the necessary precursor 17 ′ of the internal wiring portion 17 is formed on the green sheet. The conductive paste as a raw material for the via 16 and the internal wiring part 17 is not particularly limited as long as it is conventionally used / adopted as a package wiring board for a semiconductor integrated circuit LSI. For example, the conductive paste may comprise Ag powder, glass frit for obtaining adhesive strength, and an organic vehicle (for example, an organic mixture of ethyl cellulose and terpineol).

The first gap filler material and the second gap filler material applied on the green sheet may be the following pastes (may be used alone or in combination):
・ Paste containing silver component (silver paste containing silver particles and glass component)
-Paste containing a palladium component-Paste containing the same inorganic components as the green sheet (for example, alumina powder and glass component)-Paste containing a copper component

In step (i), the first gap filler precursor (51A, 51B) is formed on the green sheet 10A by application of the first gap filler material, whereas the green sheet is applied by application of the second gap filler material. A second gap filler precursor (52A, 52B) is formed at 10B. "Green sheet 10A provided with first gap filler precursor (51A, 51B)" and "Green sheet 10B provided with second gap filler precursor (52A, 52B)" The chip-type electronic components are disposed directly opposite to each other with a chip-type electronic component interposed therebetween. In that respect, the first gap filler precursor (51A, 51B) and the second gap filler precursor (52A, 52B) are disposed in the peripheral region of the electrode portion 42 of the chip-type electronic component 40 when the green sheets are stacked. They are positioned so as to be arranged (see FIG. 8). For example, as shown in FIG. 8, the first gap filler precursor (51A, 51B) and the second gap filler precursor (52A, 52B) are arranged along the outer peripheral edge of the electrode portion (see FIG. It is formed in the shape of a letter “)”. As shown in FIGS. 7 and 8, the second gap filler precursor (52A, 52B) is at least partially in contact with the “internal wiring portion precursor 17 ′” formed in advance on the green sheet. As such, it may be formed on its precursor 17 '.

Next to step (i), step (ii) is performed. That is, a plurality of green sheets are stacked to form a green sheet stack (see FIGS. 9 and 10). In particular, as shown in FIG. 10B, the first gap filler precursor (51A, 51B) and the second gap filler precursor (52A, 52B) are directly opposed to each other. The chip-type electronic component 40 is sandwiched and laminated between the green sheet 10A and the green sheet 10B.

When sandwiching the chip-type electronic component, as shown in FIG. 11, in the peripheral region of the electrode part 42 (42A, 42B) of the chip-type electronic component 40, the first gap filler precursor (51A, 51B) and the first Two gap filler precursors (52A, 52B) are brought into contact with each other. Thereby, a gap filler precursor in which the first gap filler precursor (51A, 51B) and the second gap filler precursor (52A, 52B) are integrated is formed. In particular, in each peripheral region of the two electrode portions (42A, 42B) of the chip-type electronic component 40, the first gap filler precursor (51A, 51B) and the second gap filler precursor (52A, 52B) Are preferably integrated with each other.

The number of green sheets in the green sheet laminate is not particularly limited, and may be, for example, about 3 to 50 in total, preferably about 3 to 15 sheets.

Next to step (ii), step (iii) is performed. That is, the ceramic laminate 10 is obtained by firing the green sheet laminate. In particular, in the present invention, prior to firing or prior to firing, the green sheet laminate is pressed in the thickness direction from the outside to the inside, and the fillet-like gap filler 50 is formed from the integrated gap filler precursor ( FIG. 11 and FIG. 12 (a)).

The green sheet laminate is preferably subjected to an organic substance decomposition / desorption treatment (binder burnout treatment) such as a binder removal step prior to firing. For example, as the binder removal step, heat treatment may be performed for 20 to 50 hours under a temperature condition of 500 ° C. to 700 ° C.

In firing, the green sheet laminate is preferably heat-treated at a temperature of 800 ° C. to 1000 ° C. (preferably 850 ° C. to 950 ° C.) for about 0.1 hours to 3 hours. The condition is preferably 0.2 to 2.0 MPa (for example, 0.3 to 1.0 MPa). The heat treatment itself may be performed by subjecting the green sheet laminate to a firing furnace such as a mesh belt furnace. On the other hand, the pressure treatment may be performed using a conventional press member or the like.

In addition, it is preferable to use a “constraint layer” when carrying out the step (iii). Specifically, as shown in FIGS. 9 to 11, a constraining layer 60 is provided on the outside of the green sheet laminate, and the green sheet laminate is pressed in the thickness direction from the outside to the inside via the constraining layer 60. It is preferable to do.

By providing the constraining layer 60, the green sheet laminate (10A, 10B, 10C,...) Does not shrink in the horizontal direction during firing, but shrinks only in the vertical direction. In other words, the green sheet laminate (10A, 10B, 10C,...) Does not contract along a direction parallel to the main surface of the green sheet, and can contract only along a direction orthogonal to the main surface. . Therefore, it can be said that the constraining layer 60 can be used for suppressing the horizontal contraction of the green sheet and contracting only in the thickness direction to obtain the ceramic substrate portion.

For example, the constraining layer 60 is a sheet formed by mixing alumina powder with the same organic material as the green sheet, and preferably has the same outer size as the green sheet. The thickness dimension of the constraining layer 60 is preferably about 100 to 350 μm.

When the constraining layer 60 is removed after heating and pressing, a spraying process may be performed. For example, the constraining layer 60 can be removed by spraying a mixture of water and alumina powder onto the constraining layer 60. As an example, the removal process of the constraining layer 60 is performed by spraying a mixture of about 96 g of water and about 4 g of alumina having an average particle diameter of 0 to 10 μm on the constraining layer 60 with compressed air having a pressure of about 0.4 MPa. It can be carried out.

When the step (iii) is completed, as shown in FIG. 12 (a), the ceramic substrate portion 10, the chip-type electronic component 40 and the fillet-like gap filler 50 disposed inside the ceramic substrate portion are provided. A ceramic substrate 100 is obtained.

As shown in FIG. 12A, FIG. 1 or the like, the fillet-like gap filling material 50 is obtained in contact with the electrode part 42 of the chip-type electronic component and also with the internal wiring part 17. . Therefore, if the fillet-like gap filler 50 has conductivity, the electrical connection between the internal wiring part 17 and the electrode part 42 of the chip-type electronic component is strengthened, and as a result, the connection between them. Reliability can be improved.

For the obtained ceramic substrate 100, as shown in FIG. 12B, an external electrode portion 19 and an electronic circuit pattern wiring portion 20 may be formed as necessary. For example, the conductor paste is printed so as to have a desired pattern by a screen printing method, and then “temperature at which the printed conductor paste is sufficiently fired” and “temperature lower than the firing temperature of the green sheet laminate” The external electrode portion 19 and the electronic circuit pattern wiring portion 20 can be formed by subjecting to a heat treatment under conditions. As a conductive paste used for forming the external electrode portion 19 and the electronic circuit pattern wiring portion 20, a silver paste (for example, a conductive paste containing Ag particles and a glass component) having a firing temperature of about 680 to 720 ° C. is used. In such a case, the heat treatment may be performed under a temperature condition of about 730 to 770 ° C. The external electrode portion 19 and the electronic circuit pattern wiring portion 20 may be formed by using photolithography and wet etching. For example, a copper thin film is formed by a wet plating method (such as an electroless plating method or an electroplating method), followed by patterning on the copper thin film using a photoresist, and then performing etching, whereby the external electrodes 19 and the electrons are formed. The circuit pattern wiring part 20 and the like can be formed. In such a case, after firing the green sheet laminate containing the chip-type electronic component, no further heat treatment is required, and a higher-density electronic circuit pattern (ie, a narrower wiring interval) and external electrodes are created. it can. That is, it is particularly suitable for the production of a ceramic substrate for electronic circuits that requires high-density mounting.

Through the above process, a ceramic substrate 100 as shown in FIG. 12B or FIG. 5 can be obtained.

(Gap filler material / Gap filler precursor)
Next, the “gap filler material / gap filler precursor” used in the production process of the present invention will be described in detail.

The first gap filler material and the second gap filler material used in the production method of the present invention may be a silver paste containing silver particles and a glass component. Such a silver paste can be deformed by an external force during the heat-pressing process during the manufacturing process, so that “a void portion that can be generated in the vicinity of an electrode of a chip-type electronic component” can be suitably filled. That is, when a silver paste is used, a desired fillet-like gap filler can be formed in the peripheral region of the electrode portion. Since the silver paste itself can be obtained relatively inexpensively and does not increase the number of materials for manufacturing the substrate, it leads to low-cost manufacturing of the ceramic substrate.

Further, the first gap filler material and the second gap filler material may be a conductive paste containing palladium. Such a palladium-containing paste increases in volume due to oxidation of palladium during the heat-pressing process during the manufacturing process, and as a result, the effect of filling the gap can be improved. That is, when a palladium-containing paste is used, a desired fillet-like gap filler can be formed in the peripheral region of the electrode part of the chip-type electronic component.

Further, the first gap filler material and the second gap filler material may be formed from a paste containing the same inorganic components (for example, alumina powder and glass component) as the green sheet. When the “paste containing the same inorganic components as the green sheet” is used, the shrinkage ratio of the green sheet and the shrinkage ratio of the gap filler paste can be made substantially the same during firing during the manufacturing process. Stable firing is possible. Therefore, as a result, when “a paste containing the same inorganic component as the green sheet” is used, a desired fillet-like gap filler can be formed in the peripheral region of the electrode part of the chip-type electronic component. In addition, since such paste itself can be obtained at the time of preparation of a green sheet, it does not increase the number of materials for substrate production, and leads to low-cost production of a ceramic substrate.

Furthermore, the first gap filler material and the second gap filler material may additionally contain a copper component. This is because the thermal conductivity of the gap filler can be improved by the copper component, and a substrate with particularly excellent heat dissipation characteristics can be obtained.

As shown in FIG. 10, “one green sheet 10A coated with the first gap filler material” is arranged vertically upward (vertically upper side), while “the other green sheet coated with the second gap filler material”. In the case where the sheet 10B "is arranged vertically downward (vertically below), it is preferable that the application amount of the second gap filler material is larger than the application amount of the first gap filler material. A fillet-like gap filler can be suitably formed in the peripheral region. For example, the coating amount of the second gap filler material is preferably 3% to 60% by weight, more preferably 5% to 40% by weight, and even more preferably 10%, more than the coating amount of the first gap filler material. Increase by weight percent to 30 weight percent.

Further, when viewed along the opposing direction of the two electrode portions of the chip-type electronic component, the inner end portion of the coating film (precursor disposed vertically below) of the second gap filler precursor (52A, 52B) is It is preferable to sandwich the chip-type electronic component so that it is positioned 0.2 to 0.5 mm away from the center of the chip-type electronic component (see FIG. 13). That is, it is preferable to sandwich the chip-type electronic component 40 so that the separation distance L shown in FIG. 13 is 0.2 to 0.5 mm. Such process conditions also lead to the formation of the desired fillet-like gap filler.

Further, the thickness of the coating film of the second gap filler precursor (52A, 52B) is preferably 60 to 150 μm, more preferably 80 to 130 μm (see FIG. 13). That is, it is preferable to sandwich the chip-type electronic component under the condition that the thickness dimension T shown in FIG. 13 is preferably 60 to 150 μm, more preferably 80 μm to 130 μm. Such process conditions also lead to the formation of the desired fillet-like gap filler.

As mentioned above, although the embodiment of the present invention has been described, a typical example is merely illustrated. Therefore, the present invention is not limited to this, and various modes are conceivable.

Finally, it should be confirmed that the present invention has the following aspects.
1st aspect : It has a ceramic substrate part formed by baking (sintering) of the laminated body of several green sheets, and the chip type electronic component distribute | arranged inside the ceramic substrate part, Chip type | mold electronic A ceramic substrate (ceramic multilayer substrate) provided with a gap filling material (gap filling portion) formed in a fillet shape in the peripheral region of the electrode portion of the component.
Second aspect : The ceramic substrate according to the first aspect, wherein the thickness of the gap filler gradually decreases along the direction from the position of the chip-type electronic component toward the outside.
Third aspect : The ceramic substrate according to the first aspect or the second aspect, wherein the fillet-shaped gap filler is in partial contact with the electrode portion of the chip-type electronic component.
Fourth aspect : In any one of the first to third aspects, the ceramic substrate portion further includes an internal wiring portion, and the fillet-like gap filler partially contacts the internal wiring portion. A ceramic substrate (particularly in the case of being subordinate to the third aspect, a ceramic substrate in which a fillet-like gap filler is in contact with both the electrode part and the internal wiring part of the chip-type electronic component) .
Fifth aspect : In any one of the first to fourth aspects, the fillet-shaped gap filler has a ratio of the maximum width dimension Wmax to the maximum thickness dimension Tmax (Wmax / Tmax) of 3 to 15. Ceramic substrate.
Sixth aspect : In any one of the first to fifth aspects, the chip-type electronic component has two electrode portions facing each other, and the gap filler is a fillet in the peripheral region of each of the two electrode portions. A ceramic substrate provided in a shape.
Seventh aspect : The ceramic substrate according to any one of the first to sixth aspects, wherein the fillet-like gap filler contains a silver component.
Eighth aspect : The ceramic substrate according to any one of the first to seventh aspects, wherein the fillet-like gap filler contains a palladium component.
Ninth aspect : The ceramic substrate according to any one of the first to eighth aspects, wherein the fillet-like gap filler contains the same inorganic component as the green sheet.
A tenth aspect : a method of manufacturing a ceramic substrate comprising a ceramic substrate portion and chip-type electronic components disposed inside the ceramic substrate portion,
(I) For two green sheets selected from a plurality of green sheets, a first gap filler material is applied to one green sheet to form a first gap filler precursor, and Applying a two-gap filler material to form a second gap-filler precursor;
(Ii) A step of laminating a plurality of green sheets to form a green sheet laminate, wherein the first gap filler precursor and the second gap filling when the one green sheet and the other green sheet are laminated A step of sandwiching a chip-type electronic component between the one green sheet and the other green sheet in a state where the material precursor faces directly, and (iii) firing the green sheet laminate And a step of obtaining a ceramic substrate portion,
When sandwiching the chip-type electronic component, in the peripheral region of the electrode portion of the chip-type electronic component, the first gap filler precursor and the second gap filler precursor are aligned with each other and integrated with each other. The filler precursor is formed, and when firing, the green sheet laminate is pressed in the thickness direction from the outside to the inside, thereby “filling the gap filler into an integrated gap”. A method for producing a ceramic substrate, comprising:
Eleventh aspect : In the tenth aspect, when the chip-type electronic component is sandwiched, the one green sheet coated with the first gap filler material is disposed vertically upward, while the second gap filler material is coated. The other green sheet is placed vertically downward,
A method for producing a ceramic substrate, wherein the amount of application of the second gap filler material is greater than the amount of application of the first gap filler material.
Twelfth aspect : A method for producing a ceramic substrate according to the eleventh aspect, wherein the thickness of the second gap filler precursor (coating film) is 60 to 150 μm.
Thirteenth aspect : In any one of the tenth to twelfth aspects, the chip electronic component has two electrode portions facing each other,
When sandwiching a chip-type electronic component, the first gap filler precursor and the second gap filler precursor are integrated with each other in the peripheral region of each of the two electrode portions, and the ceramic A method for manufacturing a substrate.
14th aspect : In said 13th aspect, when it sees along the opposing direction of two electrode parts, the inner side edge part of a 2nd clearance gap material precursor (coating film) is 0.2 from the center part of a chip-type electronic component. A method of manufacturing a ceramic substrate, wherein a chip-type electronic component is sandwiched so as to be positioned at a distance of ~ 0.5 mm.
Fifteenth aspect : In any one of the tenth to fourteenth aspects, a constraining layer is formed on the opposing outer main surface of the green sheet laminate, and the green sheet laminate is formed from the outside to the inside through the constraining layer. A method of manufacturing a ceramic substrate, characterized by pressing in the thickness direction.

Various tests were conducted on matters related to the present invention.

Specifically, a ceramic substrate as shown in FIG. 14 was prepared by test according to the present invention, and a “moisture absorption reflow test”, a “high temperature storage test”, and a “temperature cycle test” were performed (see Table 1).

The results are shown in FIG. As can be seen from the graph shown in FIG. 15, it was confirmed that the ceramic substrate produced according to the present invention had satisfactory quality characteristics.

Next, a “confirmation test on the arrangement effect of the gap filler precursor” was performed. In particular, as shown in FIG. 16, a test was conducted on the arrangement effect of the gap filler precursor arranged on the lower side. Specifically, the effect was examined by changing the horizontal separation distance between the second gap filler precursor and the chip-type electronic component. As a result, as shown in FIG. 16, when the horizontal separation distance is about 0.2 to 0.5 mm, a “fillet-like gap filling material” can be suitably formed (particularly, “short” is possible). It has been confirmed that a ceramic substrate with satisfactory quality characteristics can be obtained.

Next, a “confirmation test on the thickness effect of the gap filler precursor” was performed. In particular, as shown in FIG. 17, a test was conducted for the thickness effect of the gap filler precursor disposed on the lower side. Specifically, the effect was investigated by changing the thickness dimension of the second gap filler precursor. As a result, as shown in FIG. 17, when the thickness of the second gap filler precursor is about 60 to 150 μm (particularly about 80 μm to 130 μm), a “fillet-like gap filler” is suitably formed. It was confirmed that a ceramic substrate having satisfactory quality characteristics could be obtained (especially, the conductor thickness was increased and the connection between the electronic component and the conductor was strengthened).

The ceramic substrate according to the present invention is suitably used as an RF module of a mobile device, a power LED substrate using heat dissipation, or an LED substrate for a liquid crystal backlight, and an electronic component mounted with high density. It is also suitably used as a substrate for equipment.

In particular, the present invention can improve the yield of the manufacturing process of the ceramic multilayer substrate with the built-in chip type electronic components, so that the backlight LED for LCD screens of liquid crystal televisions and mobile phones, which have recently been widely used, is used. Highly expected to be used as a substrate.
Cross-reference of related applications

This application claims priority under the Paris Convention based on Japanese Patent Application No. 2010-123984 (filing date: May 31, 2010, title of the invention "ceramic multilayer substrate and method for producing ceramic multilayer substrate") To do. All the contents disclosed in the application are incorporated herein by this reference.

Claims

A ceramic substrate,
A ceramic substrate portion formed by firing a laminate of a plurality of green sheets, and a chip-type electronic component disposed inside the ceramic substrate portion,
A ceramic substrate, further comprising a gap filler formed in a fillet shape in a peripheral region of the electrode portion of the chip-type electronic component.
2. The ceramic substrate according to claim 1, wherein the thickness of the gap filler gradually decreases along the direction from the chip-type electronic component toward the outside.
The ceramic substrate according to claim 1, wherein the gap filling material is in partial contact with the electrode portion of the chip-type electronic component.
It has an internal wiring part inside the ceramic substrate part,
The ceramic substrate according to claim 1, wherein the gap filler is in partial contact with the internal wiring portion.
2. The ceramic substrate according to claim 1, wherein a ratio (Wmax / Tmax) of a maximum width dimension Wmax to a maximum thickness dimension Tmax of the gap filler is 3 to 15.
The chip-type electronic component has two electrode portions facing each other, and the gap filler is provided in a fillet shape in a peripheral region of each of the two electrode portions. A ceramic substrate as described in 1.
The ceramic substrate according to claim 1, wherein the gap filler contains a silver component.
The ceramic substrate according to claim 1, wherein the gap filler contains a palladium component.
The ceramic substrate according to claim 1, wherein the gap filling material contains the same inorganic component as the green sheet.
A method of manufacturing a ceramic substrate having a ceramic substrate portion and chip-type electronic components disposed inside the ceramic substrate portion,
(I) For two green sheets selected from a plurality of green sheets, a first gap filler material is applied on one green sheet to form a first gap filler precursor, and on the other green sheet Applying a second gap filler material to the second gap filler precursor,
(Ii) a step of laminating the plurality of green sheets to form a green sheet laminate, wherein the first gap filler precursor and the first green sheet and the other green sheet are laminated, A step of sandwiching a chip-type electronic component between the one green sheet and the other green sheet with the second gap filler precursor facing each other; and (iii) the green sheet lamination Comprising subjecting the body to firing to obtain a ceramic substrate portion,
When sandwiching the chip-type electronic component, the first gap filler precursor and the second gap filler precursor are aligned with each other in the peripheral region of the electrode portion of the chip-type electronic component, and they are integrated. Forming the gap filler precursor, and during the firing, the green sheet laminate is pressed in the thickness direction from the outside to the inside, thereby forming a fillet shape from the integrated gap filler precursor. A method for producing a ceramic substrate, wherein the gap filler is formed.
In the case where the one green sheet is disposed vertically upward while the other green sheet is disposed vertically downward when the chip-type electronic component is sandwiched, the coating amount of the second gap filler material is set to the first amount. The method for producing a ceramic substrate according to claim 10, wherein the amount is larger than a coating amount of the gap filler material.
12. The method for manufacturing a ceramic substrate according to claim 11, wherein a thickness dimension of the second gap filler precursor is 60 to 150 μm.
The chip electronic component has two electrode portions facing each other,
When sandwiching the chip-type electronic component, the first gap filler precursor and the second gap filler precursor are integrated and integrated with each other in the peripheral region of each of the two electrode portions. The method for manufacturing a ceramic substrate according to claim 10, wherein the method is characterized in that:
The chip is arranged such that the inner end of the second gap filler precursor is positioned 0.2 to 0.5 mm away from the center of the chip-type electronic component along the opposing direction of the two electrode parts. The method for manufacturing a ceramic substrate according to claim 13, wherein the mold electronic component is sandwiched.
The constraining layer is provided on the outer surface of the green sheet laminate, and the green sheet laminate is pressed in the thickness direction from outside to inside through the constraining layer in the step (iii). A method for producing a ceramic substrate as described in 1.