JP2004235206A - Ceramic multilayer circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic multilayer circuit board whose air-tightness and reliability can be improved. <P>SOLUTION: In the ceramic multilayer circuit board, a plurality of insulating layers composed of ceramic are laminated and a nearly rectangular laminated body 1 is formed. A plurality of recessed parts 3 covered with terminal electrodes 2 inside are formed on the sides of the laminated body 1. An inner conductor 5a which is electrically connected to the terminal electrode 2 is installed between the insulating layers of the laminated body 1. The inner conductor film 5a has a recessed land 7 disposed in a connection part with the terminal electrode 2 along a recessed inner face. Both ends of the recessed land 7 are installed by detaching them from the sides of the laminated body 1. The land 7 is connected to the terminal electrode 2 in a region on a side inner than detached parts. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a ceramic multilayer circuit board suitable for an electronic device in which electronic components such as a semiconductor element and a piezoelectric element are hermetically sealed and mounted, and a method for manufacturing the same.
[0002]
[Prior art]
2. Description of the Related Art Ceramic multilayer circuit boards have been widely used in electronic devices for mounting and electronically sealing electronic components such as semiconductor elements and piezoelectric elements.
[0003]
As such a conventional ceramic multilayer circuit board, for example, as shown in FIG. 4, a plurality of insulating layers made of ceramic are laminated to form a substantially rectangular laminate 41, and a side surface of the laminate 41 has an inner surface. There is known a structure in which a plurality of concave portions 43 having terminal electrodes attached thereto are formed, and a circuit conductor film 45 mainly composed of a metal such as Ag or Cu is provided on the surface and inside of the laminated body 41. An electronic component element such as a semiconductor element or a piezoelectric element is mounted on the main surface and hermetically sealed.
[0004]
Further, the circuit conductor film 45 of the ceramic multilayer circuit board described above is provided on the surface of the multilayer body 41 with the internal conductor film interposed between the insulating layers and electrically connected to the terminal electrodes. And a surface conductive film connected thereto, and a plating film is coated on the surface of the surface conductive film in order to improve the connectivity with the electronic component element.
[0005]
In addition, as a material of each insulating layer constituting the laminated body 41, a ceramic material such as glass-ceramic which can be fired at a low temperature is employed.
[0006]
In the case of manufacturing the above-mentioned conventional ceramic multilayer circuit board, a conventionally well-known green sheet laminating method and a method of “multiple pieces” are usually employed. Specifically, first, a plurality of ceramic green sheets each having a conductive film adhered to the surface are laminated to form a predetermined laminated sheet, and a plurality of through-holes corresponding to the concave portions are formed at predetermined positions of the laminated sheet. A hole is formed, then a conductor film to be a terminal electrode is applied to the inner surface of the through hole, and the laminated sheet is fired. Finally, the laminated sheet is cut so as to cross the concave portion, thereby forming a ceramic multilayer as a product. A circuit board is obtained.
[0007]
[Patent Document 1]
JP-A-62-281359 [0008]
[Problems to be solved by the invention]
According to the above-described conventional ceramic multilayer circuit board, a concave land portion is formed along the inner surface of the concave portion at the end of the internal conductor film connected to the terminal electrode. Are extended to the side surfaces of the laminate 41. Therefore, both ends of the land portion are exposed to the side surfaces of the laminated body 41, and oxygen or moisture in the atmosphere intrudes from the interface between the exposed land portion and the insulating layer, etc., and the ceramic multilayer circuit is formed. There is a disadvantage that the airtightness of the substrate is reduced, or the land portion exposed on the side surface of the laminated body 41 is corroded by contact with oxygen, moisture, or the like in the air. It has a drawback of lowering reliability.
[0009]
In particular, when the circuit conductor film is formed of a low melting point material such as Ag or Cu, it is extremely difficult to match the shrinkage behavior between the circuit conductor film and the insulating layer. In this case, the physical adhesion between the two is reduced, and the airtightness of the ceramic multilayer circuit board is particularly likely to deteriorate.
[0010]
The present invention has been devised in view of the above drawbacks, and has as its object to provide a ceramic multilayer circuit board capable of improving hermeticity and reliability, and a method of manufacturing the same.
[0011]
[Means for Solving the Problems]
The ceramic multilayer circuit board of the present invention has a structure in which a plurality of insulating layers made of ceramic are laminated to form a substantially rectangular laminate, and a plurality of the laminates having side surfaces and terminal electrodes adhered to the inner surface. In a ceramic multilayer circuit board having a concave portion and an internal conductor film electrically connected to the terminal electrode interposed between insulating layers of the laminate, the internal conductor film may be connected to the terminal electrode. The concave land portion is disposed along the inner surface of the concave portion, and both ends of the concave land portion are arranged to be separated from the side surface of the laminate, and the land is formed in a region inside the separated portion. And a terminal connected to the terminal electrode.
[0012]
Further, in the ceramic multilayer circuit board according to the present invention, the internal conductor film is made of a conductor material containing a metal as a main component.
[0013]
Further, in the ceramic multilayer circuit board of the present invention, a surface conductor film electrically connected to the terminal electrode via the internal conductor film is coated on the surface of the laminate, and the surface conductor film is It is characterized in that a plating film is adhered to the surface.
[0014]
Still further, in the ceramic multilayer circuit board according to the present invention, an electronic component element is mounted on the laminate, and a connection terminal of the electronic component element and the plating film are electrically connected via a conductive adhesive. It is characterized by the following.
[0015]
Still further, in the ceramic multilayer circuit board according to the present invention, the plating film is made of nickel and has a thickness of 0.5 μm or more.
[0016]
Still further, in the ceramic multilayer circuit board according to the present invention, the plating film is made of gold and has a thickness of 0.05 μm or more.
[0017]
In the method for manufacturing a ceramic multilayer circuit board according to the present invention, the laminated body of the ceramic multilayer circuit board may have a through-hole corresponding to the recess, and the laminated sheet on which a plating film is adhered may be provided in the recess. And cut out so as to cross it.
[0018]
[Action]
According to the present invention, the concave land portion of the internal conductor film connected to the terminal electrode is arranged so that both ends thereof are separated from the side surface of the multilayer body, and the terminal electrode is formed in a region inside the separated portion. Since the connection is made, the land portion is not exposed to the side surface of the laminate at all, and oxygen and moisture contained in the air enter the inside from the side surface of the laminate, and the land portion is not exposed. Corrosion due to contact with oxygen, moisture and the like contained in the atmosphere is effectively prevented. Therefore, the airtightness of the ceramic multilayer circuit board can be maintained high, and the reliability thereof is also improved.
[0019]
According to the present invention, a plating film made of Ni having a thickness of 0.5 μm or more or Au having a thickness of 0.05 μm or more is applied to the surface of the surface conductor film provided on the surface of the laminate. By doing so, the surface conductor film can be well covered with the plating film, and in this case, the interface between the surface conductor film and the insulating layer is not exposed to the outside, so that the airtightness of the ceramic multilayer circuit board is improved. It can be kept high.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an external perspective view of a ceramic multilayer circuit board according to an embodiment of the present invention, FIG. 2 is an enlarged perspective view of a main part of the ceramic multilayer circuit board of FIG. 1, and the electronic device shown in FIG. It has a structure in which an insulating layer is laminated to form a substantially rectangular laminate 1, and a plurality of recesses in which terminal electrodes 2 are attached and formed on the inner surface are formed on side surfaces of the laminate 1. In addition, a circuit conductor film that is electrically connected to the terminal electrode 2 is provided on the surface and inside of the laminate 1.
[0021]
The laminate 1 is configured by laminating a plurality of insulating layers made of a ceramic material such as glass-ceramic that can be fired at a relatively low temperature of, for example, 800C to 1200C. Examples of the ceramic component of the glass-ceramic material include insulating ceramic materials such as cristobalite, quartz, corundum (α-alumina), mullite, cordierite, dielectric ceramic materials such as MgTiO ₃ , CaTiO ₃ , BaTiO ₃ , and TiO ₂ ; Magnetic ceramic materials such as Ni-Zn ferrite and Mn-Zn ferrite are used, and for example, those pulverized to an average particle size of 0.5 to 6.0 µm, preferably 0.5 to 2.0 µm are used. . Note that two or more ceramic materials may be used in combination.
On the other hand, as the glass component of the glass-ceramic material, a crystal phase of cordierite, mullite, anorthite, serdian, spinel, garnite, willemite, dolomite, petalite or a substituted derivative thereof or a crystal phase having a spinel structure is precipitated by firing. well with whatever glass long as, for _{example, B 2 O 3, SiO 2} , Al 2 O 3, ZnO, glass frit containing an alkaline earth oxide. These glass frit have a wide vitrification range, and a sag point is set at, for example, 600 to 800 ° C.
[0022]
Note that the thickness of each insulating layer forming the laminate 1 is set, for example, to 20 μm to 300 μm.
[0023]
The terminal electrode 2 on the inner surface of the concave portion provided on the side surface 4 of the laminated body 1 functions as an external connection terminal for connecting the ceramic multilayer circuit board 10 to an external circuit such as a motherboard. It is electrically connected to wiring and the like via a conductive adhesive such as solder.
[0024]
The concave portion 3 on which the terminal electrode 2 is attached to the inner surface is formed, for example, in a semi-cylindrical shape, and when the ceramic multilayer circuit board 10 is connected to an external circuit, the concave portion 3 is formed inside the terminal electrode 2. The conductive adhesive to be joined is accommodated.
[0025]
The circuit conductor film 5 provided on or on the surface of the laminate 1 is made of a conductive material mainly containing a metal such as silver or copper. The circuit conductor film 5 is provided on the surface of the laminate 1. It is composed of a surface conductor film, an internal conductor film 5a interposed between insulating layers, and a via-hole conductor buried inside the insulating layer.
[0026]
The surface conductor film is electrically connected to connection terminals of electronic component elements such as a semiconductor element and a piezoelectric element mounted on the main surface of the laminate 1 via solder, gold bumps, or the like, One end thereof is electrically connected to the terminal electrode 2 on the inner surface of the concave portion via an internal conductor film 5a and a via-hole conductor described later.
[0027]
On the surface of such a surface conductor film, a nickel (Ni) plating film for hardening the surface conductor film to enhance resistance to solder cracking, and a gold film for improving the bonding property with solder, gold bumps and the like. (Au) A plating film or the like is applied, and the surface of the surface conductor film is completely covered with these plating films. Here, it is preferable that the thickness of the nickel plating film is set to 0.5 μm or more, and the thickness of the gold plating film is set to 0.05 μm or more.
[0028]
On the other hand, the internal conductor film 5a has a concave land portion 7 arranged along the inner surface of the concave portion at the connection portion with the terminal electrode 2, and both ends of the concave land portion 7 are connected to the side surface of the laminated body 1. The land portions 7 are connected to the terminal electrodes 2 in a region inside the separated portions, while being further separated from each other.
[0029]
With such a structure, the land portions 7 of the internal conductor film 5a are not exposed on the side surfaces 4 of the multilayer body 1, so that oxygen, moisture, and the like contained in the air penetrate inside from the side surfaces of the multilayer body 1. In addition, the land portion is effectively prevented from being corroded by contact with oxygen, moisture or the like contained in the atmosphere, and the airtightness and reliability of the ceramic multilayer circuit board 10 can be improved.
[0030]
Further, in this case, a nickel plating film having a thickness of 0.5 μm or more or a gold plating film having a thickness of 0.05 μm or more is adhered to the surface of the surface conductor film, and the surface conductor film is preferably formed by a plating film. As a result, the interface between the surface conductor film and the insulating layer is not exposed to the outside, thereby improving the airtightness of the ceramic multilayer circuit board 10.
[0031]
The material of the circuit conductor film 5 is selected in consideration of compatibility with the dielectric material forming the insulating layer. For example, when the circuit conductor film 5 is formed of a conductive material mainly containing silver or copper, The thickness is set to, for example, 5 to 25 μm. The diameter of the via-hole conductor is appropriately set according to the thickness of the insulating layer and the like. When the thickness of the insulating layer in which the via-hole conductor is embedded is 20 μm to 300 μm, the diameter of the via-hole conductor is set to, for example, 50 μm to 300 μm. .
[0032]
Thus, the above-described ceramic multilayer circuit board 10 has a predetermined electronic device by mounting electronic component elements on its main surface, hermetically sealing it, and mounting and connecting it on an external circuit such as a motherboard. .
[0033]
Next, a manufacturing method for manufacturing the above-described laminated body 1 of the ceramic multilayer circuit board 10 by a conventionally well-known green sheet laminating method will be described.
[0034]
First, as shown in FIG. 3, a laminated sheet 21 having a plurality of substrate regions corresponding to the laminated body 1 is prepared, and a through hole 22 corresponding to the recess 2 is adjacent to each substrate region of the laminated sheet 21. It is formed continuously so as to straddle between substrate regions.
[0035]
At this time, the laminated sheet 21 is formed by laminating a predetermined number of ceramic green sheets obtained by adding an appropriate organic binder or the like to the ceramic raw material powder for forming the insulating layer of the laminated body 1. Before laminating the ceramic green sheets, a predetermined portion of the uppermost layer or several layers of ceramic green sheets continuing downward from the uppermost layer is punched out with a punch or the like, and formed by drilling through holes 22 in the ceramic green sheets. You. At this time, the through hole 22 is formed at a portion where the side portions of two adjacent substrate regions are in contact with each other.
[0036]
Next, a cutting groove is formed at the boundary 23 between the substrate regions by, for example, a cutter blade, and the laminated sheet 21 obtained in the previous step is fired at a high temperature. Then, after coating the circuit conductor film disposed on the surface of the laminated sheet 21 with plating, the laminated sheet 21 is cut along the boundaries 23 between the substrate regions, thereby cutting out a plurality of substantially rectangular laminates 1.
[0037]
The cutting of the laminated sheet 21 is performed, for example, by applying pressure from both upper and lower surfaces of the laminated sheet 21 to divide the laminated sheet 21 from a groove formed at the boundary 23 between the substrate regions as a starting point (a so-called chocolate break). As a result, a plurality of substantially square laminates 1 are manufactured at the same time.
[0038]
What is important in the above manufacturing method is that the internal conductor film 5a connected to the terminal electrode 2 on the inner surface of the concave portion is connected to the terminal electrode 2 via the land portions 7 whose both ends are separated from the side surface of the multilayer body 1. (See FIG. 2).
[0039]
As described above, since the internal conductor film 5 connected to the terminal electrode 2 is connected to the terminal electrode 2 via the land portion 7 separated from the side surface 4 of the multilayer body 1, when cut from the multilayer sheet 21, The edge of the land portion 7 and the interface between the land portion 7 and the insulating layer are not exposed on the side surface 4 of the multilayer body 1, and a path through which oxygen, moisture, or the like contained in the air enters can be cut off. .
[0040]
In addition, even when the circuit conductor film 5 is formed from a low-melting conductive material containing silver or copper, and the laminate 1 is formed from a ceramic material that can be fired at a low temperature, the circuit conductor film 5 is insulated from the circuit conductor film. The hermeticity of the ceramic multilayer circuit board is not greatly reduced due to the difference in the shrinkage behavior of the layers, and the reliability of the electronic component element mounted hermetically on the main surface of the multilayer body 1 is also improved. it can.
[0041]
Note that the present invention is not limited to the above-described embodiment, and various changes, improvements, and the like can be made without departing from the gist of the present invention.
[0042]
For example, in the above-described embodiment, the laminated body 1 is cut out from the laminated sheet 21 by a so-called “chocolate break”. Instead of this, the laminated sheet 21 may be cut by dicing or the like. Absent. Cutting by such a method is effective for dividing a laminated sheet in which almost the entire area is resin-molded.
[0043]
Further, the electronic component element mounted on the main surface of the multilayer body 1 may be housed in a concave portion (cavity) provided on the main surface of the multilayer body 1 and hermetically sealed. According to this, the height of the electronic device can be reduced.
[0044]
Further, in the above-described embodiment, the shape of the concave portion 3 is a semi-cylindrical shape, and the shape of the land portion 7 is a fan shape. It doesn't matter.
[0045]
【The invention's effect】
According to the present invention, the concave land portion of the internal conductor film connected to the terminal electrode is arranged so that both ends thereof are separated from the side surface of the multilayer body, and the terminal electrode is formed in a region inside the separated portion. Since the connection is made, the land portion is not exposed to the side surface of the laminate at all, and oxygen and moisture contained in the air enter the inside from the side surface of the laminate, and the land portion is not exposed. Corrosion due to contact with oxygen, moisture and the like contained in the atmosphere is effectively prevented. Therefore, the airtightness of the ceramic multilayer circuit board can be maintained high, and the reliability thereof is also improved.
[0046]
According to the present invention, a plating film made of Ni having a thickness of 0.5 μm or more or Au having a thickness of 0.05 μm or more is applied to the surface of the surface conductor film provided on the surface of the laminate. By doing so, the surface conductor film can be well covered with the plating film, and in this case, the interface between the surface conductor film and the insulating layer is not exposed to the outside, so that the airtightness of the ceramic multilayer circuit board is improved. It can be kept high.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a ceramic multilayer circuit board according to an embodiment of the present invention.
FIG. 2 is an enlarged perspective view of a main part of the ceramic multilayer circuit board of FIG. 1;
FIG. 3 is an external perspective view in one step for describing a method for manufacturing a ceramic multilayer circuit board according to one embodiment of the present invention.
FIG. 4 is an enlarged perspective view of a main part of a conventional ceramic multilayer circuit board.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Laminated body 2 ... Concave part 3 ... Terminal electrode 4 ... Side 5 ... Circuit conductor film 5a ... Inner conductor film 7 ... Land part 10 ... Ceramic multilayer circuit board

Claims (7)

A plurality of insulating layers made of ceramic are laminated to form a substantially square laminate, and a plurality of recesses having terminal electrodes attached to the inner surface are formed on side surfaces of the laminate, and A ceramic multilayer circuit board including an internal conductor film electrically connected to the terminal electrode between insulating layers,
The internal conductor film has a concave land portion arranged along the inner surface of the concave portion at a connection portion with the terminal electrode, and both ends of the concave land portion are arranged so as to be separated from a side surface of the laminate. In addition, the land portion and the terminal electrode are connected to each other in a region inside the separated portion. 2. The ceramic multilayer circuit board according to claim 1, wherein the internal conductor film is made of a conductor material containing a metal as a main component. A surface conductor film that is electrically connected to the terminal electrode via the internal conductor film is applied to the surface of the laminate, and a plating film is applied to the surface of the surface conductor film. The ceramic multilayer circuit board according to claim 1 or 2, wherein: 4. The ceramic according to claim 3, wherein an electronic component element is mounted on the laminate, and a connection terminal of the electronic component element and the plating film are electrically connected via a conductive adhesive. Multilayer circuit board. 4. The ceramic multilayer circuit board according to claim 3, wherein the plating film is made of nickel and has a thickness of 0.5 [mu] m or more. 4. The ceramic multilayer circuit board according to claim 3, wherein the plating film is made of gold and has a thickness of 0.05 [mu] m or more. The ceramic multilayer circuit board according to any one of claims 1 to 6, wherein the laminate has a through-hole corresponding to the concave portion, and a laminated sheet on which a plating film is attached, A method for manufacturing a ceramic multilayer circuit board, wherein the method is cut out and manufactured so as to cross a recess.

Images