JP2000196240A - Stacked circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer circuit board which has excellent conduction reliability between an internal wiring layer and a terminal electrode, and can be miniaturized. SOLUTION: In a multilayer circuit board, a recessed part 51 extending in the thickness direction of a multilayer body 1 on an end of the body 1 in which insulation layers 1a to 1e and an internal wiring layer 3 are laminated, and a conductive layer 52 which is connected to the layer 3 and extends to the thickness direction of the inner wall surface of the recessed part 51 is exposed and formed, and moreover, an electrode terminal conductive film 53 is adhered and formed on the inner wall of a penetrating recessed part 51 including the layer 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a structure of an end face electrode of a laminated circuit board.

[0002]

2. Description of the Related Art Conventionally, a laminated circuit board has a structure in which a plurality of insulating layers are laminated, and a predetermined internal wiring layer is arranged between layers of the laminated body.
A laminate was formed. Further, a predetermined surface wiring pattern is formed on the surface of the laminate, and an IC chip, an electronic component element, a thick film resistor film, a capacitor film, a protective film, and the like are formed on the surface wiring pattern as necessary. I was

Incidentally, via-hole conductors for connecting between predetermined internal wiring layers and connecting between internal wiring layers and surface wiring patterns have been formed inside the laminate.

[0004] The connection between such a laminated circuit board and an external printed wiring board is made via conductive members by terminal electrodes. Most commonly, a backside terminal electrode pad is formed on the backside of the laminate, and this backside terminal electrode is soldered to an electrode pad of a printed wiring board.

Further, a concave portion extending in the thickness direction of the laminate is formed on an end surface of the laminate, and an end terminal electrode is formed in the concave portion. A solder is provided between the end terminal electrode and an electrode pad of a printed wiring board. It is a structure to be joined.

For example, Japanese Patent Application Laid-Open No. 9-330991 discloses both terminal electrodes. In particular, the technology disclosed in Japanese Patent Application Laid-Open No. 9-330991 discloses a technique of laminating an end face side terminal electrode and a back side terminal electrode. In order to improve the conduction reliability on the outer surface of the body, the internal wiring layer and the via hole conductor inside the laminate must also have the conduction reliability on the outer surface of the laminate of the end surface terminal electrode and the back surface terminal electrode. Had improved.

[0007] Such an end face electrode forms a through-hole serving as a via-hole conductor and a terminal electrode constituting a laminate, and
A plurality of green sheets on which a conductor film serving as an internal wiring layer is formed are laminated and fired under predetermined firing conditions. A conductive film was formed by deposition.

[0008]

The connection between the conductor film on the inner wall surface of the end face electrode and the internal wiring layer is limited to the thickness of the electrode layer whose internal wiring layer is exposed from the inner wall surface of the through hole. Therefore, in order to improve the reliability of conduction between the internal wiring layer and the terminal electrode, it is necessary to form a land electrode pattern around the through hole.

As described above, when the land electrode pattern is formed around the through hole, the occupied area of the internal wiring layer including the land electrode pattern at the terminal electrode portion increases, and as a result, the size of the laminate substrate becomes large. It will become.

[0010] Such a laminated circuit board has an internal wiring layer,
Insulating green sheets on which via-hole conductors are formed are laminated and fired according to a predetermined lamination order, but formed by firing. However, processing patterns of through holes serving as via-hole conductors and printing patterns serving as internal wiring layers formed on each green sheet are formed. If the stacking and the misalignment of the green sheets occur, the connection reliability between the land electrode and the conductor film in the through hole, and the connection between the land electrode and the internal wiring layer is lacked. This leads to a decrease in the reliability of the connection between the terminal electrode and the internal wiring layer.

The present invention has been devised in view of the above-mentioned problems, and an object of the present invention is to provide a laminated circuit board which is excellent in the reliability of conduction between an internal wiring layer and a terminal electrode and which can be miniaturized. It is in.

[0012]

According to the present invention, a concave portion for a terminal electrode is formed in an end face of a laminated body formed by laminating an insulating layer and an internal wiring layer, the concave portion penetrating in the thickness direction of the laminated body. A conductor layer connected to the internal wiring layer and extending in the thickness direction was buried on the inner wall surface of the recess so as to partially expose the terminal layer, and a terminal electrode conductor film was formed on the inner wall surface of the recess. A laminated circuit board characterized by the above.

A through recess for a terminal electrode is formed through the thickness of the layered body, and a via hole conductor connected to the internal wiring layer and extending in the thickness direction of the inner wall of the through recess is formed on the inner wall surface of the through recess. A laminated circuit board, which is formed by exposing a terminal electrode conductor film on an inner wall surface of the through hole including the via hole conductor.

[0014]

As described above, according to the present invention, a terminal electrode concave portion serving as a terminal electrode is formed on the end surface of the laminate, and a conductor extending in the thickness direction of the laminate and connected to the internal wiring layer is formed on the inner wall surface. It is buried so that part of the layer is exposed. As described above, since the terminal electrode conductor film is formed on the inner wall surface where a part of the conductor layer is exposed, even if printing misalignment or lamination misalignment occurs in each green sheet, the terminal electrode (terminal electrode conductor film). ) And the internal wiring layer have stable conduction reliability.

A portion of the conductor layer exposed on the inner wall surface of the through recess is formed and formed on the green sheet in substantially the same process as the conductor film serving as the internal wiring layer.
This is because the connection between the internal wiring layer and the conductor layer is reliably performed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a laminated circuit board according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is an external perspective view of a laminated circuit board according to the present invention, FIG. 2 is a partial sectional view taken along line AA in FIG. 1, and FIG. 3 omits a terminal electrode conductor film of a terminal electrode. It is a partial perspective view of the terminal electrode of the state which carried out.

In FIG. 1, reference numeral 10 denotes a circuit board,
Is a surface conductor pattern formed on the surface of the laminate 1, 3 is an internal wiring layer (internal conductor pattern) formed in the laminate 1, 4 is a via-hole conductor formed in the laminate 1, Reference numeral 5 denotes a terminal electrode formed on the end face of the laminate 1, and reference numeral 6 denotes an electronic component.

The terminal electrode 5 is, as shown in FIG.
A plurality of conductor layers 52, a part of which is exposed on the inner wall surface of the recess 51 extending in the thickness direction of the end face of the recess 51,
It comprises a terminal electrode conductor film 53 and a plating layer.

The laminate 1 is configured by laminating insulating layers 1a to 1e. The material is, for example, a material containing alumina as a main component. Further, depending on the material of the internal conductor pattern 3, for example, low-temperature firing (800 to 1050)
C), for example, a glass in which a crystallized glass component exists around granules such as alumina powder, dielectric ceramic powder, and magnetic material (ceramic in a broad sense) powder.
Examples include ceramic materials.

Between each of the insulating layers 1a to 1e, an internal conductor pattern 3 for achieving a predetermined circuit network and generating a capacitance component and an inductor component as required is arranged.

Further, via-hole conductors 4 are formed in the insulating layers 1a to 1e so as to extend through the thickness direction of the layers.

Internal conductor pattern 3, via-hole conductor 4
Is composed of a conductor film (conductor) such as W-based, Mo-based, Ag-based (Ag alone (Ag alloy such as Ag-Pd)), Cu-based, etc., and the thickness of the internal conductor pattern 3 is about 8 to 15 μm. The diameter of 4 can be any value, for example, the diameter is 80 to 250 μm.

A surface conductor pattern 2 is formed on the surface of the laminate 1 having such a structure. The surface conductor pattern 2 is made of Au (Au alone, Au-Pt, Au-P
Au alloy such as d-type), Ag-based (Ag alone, Ag-Pd)
Ag alloy) and Cu-based (Cu simple substance or Cu alloy) conductive film. The surface line conductor pattern 2 constitutes a circuit wiring on the surface of the laminate 1 and also constitutes a connection pad of an electronic component 6 to be joined via solder, and also forms a thick film resistive film and a thick film capacitor element. Or configure terminal electrodes.

A terminal electrode 5 is formed on an end face of the multilayer circuit board 10. The terminal electrode 5 includes a concave portion 51 extending in the thickness direction of the end surface of the laminated body 1, a plurality of conductor layers 52... With the end surface exposed on the inner wall surface of the concave portion 51, a terminal electrode conductive film 53, and a plating layer 54. It is composed of

As shown in FIG. 3, the concave portion 51
Is formed so as to extend in the thickness direction formed on the end face. The concave portion 51 has a substantially semicircular or semi-elliptical opening (semicircular in the figure) in the opening shape on the surface of the laminate 1.

One or more conductor layers 52 are formed on the inner wall surface of the recess 51, and a part of the conductor layer 52, that is, the surface of the conductor layer 52 extending in the thickness direction of the laminate 1 is formed on the inner wall surface of the recess 51. It is exposed. These conductor layers 52 are made of the laminate 1
May be formed over all the insulating layers 1a to 1e.
It may be formed only on an arbitrary insulating layer and may be intermittent as a whole. In the figure, the three conductor layers 52 are all formed of the entire insulating layer 1.
It is formed so as to continue from a to 1e. Each of the conductor layers 52 may have the same position or a staggered positional relationship on the inner wall surface of the concave portion 51.

That is, due to the relationship between the inner wall surface of the concave portion 51 and the conductor layer 52, the plane shape of the conductor layer 52 is substantially circular, elliptical, or a shape in which a part of a rectangle is cut off in an arc shape.

The insulating layer 1a of the conductor layer 52 on the laminate 1 side
A land electrode pattern 55 formed around the conductor layer 52 is formed between the layers 1 to 1e.

The inner conductor pattern 53 is connected to the conductor pattern 3 to stably lead the inner conductor pattern 53 to the terminal electrode 5.
Further, it is for stably connecting the conductor layers 52 formed along the inner wall surface of the concave portion 51 of each of the insulating layers 1a to 1e.

The terminal electrode conductor film 5 is formed on the inner wall surface of the recess 51 so as to cover the conductor layer 52 exposed on the inner wall surface.
3, and a plating layer 54 is formed on the surface thereof as required.

The conductor layer 52 and the land electrode pattern 55
It is made of the same material as the internal conductor pattern 3 and the via-hole conductor 4. The terminal electrode conductor film 53 is also preferably made of an Ag-based material (Ag alone, an Ag alloy such as Ag-Pd) or a Cu-based material that can be baked at a time in the firing process of the laminate 1.

The plating layer 54 prevents solder erosion of the terminal electrode conductor film 53 when solder-bonded to a printed wiring board, and improves solderability.

For example, when the terminal electrode conductor film 53 is made of an Ag-based conductor film, the plating layer 54 is formed by Ni plating,
When the terminal electrode conductor film 53 is formed of Cu, tungsten, or molybdenum, the plating layer 54 is formed of Ni plating,
It is formed by being applied in the order of Au plating or the like.

In the laminated circuit board 10 having the above configuration, the reliability of the electrical connection between the internal conductor pattern 3 of the laminate 1 and the terminal electrode 5 is significantly improved.

This is because the internal conductor pattern 3 is led out to the terminal electrode 5 via the land electrode pattern 55. In addition, the terminal electrode conductor film 53 of the terminal electrode 5 connects the land electrode patterns 55 in the thickness direction and is formed so as to partially cover the conductor layer 52 exposed on the inner wall surface of the concave portion 51. to cause.

As described above, in addition to the thickness of the land electrode pattern 55 corresponding to the thickness of the internal conductor pattern 3, the internal conductor pattern 3 has an exposed portion in the thickness direction of the conductor layer 52 (distance in the thickness direction × exposed width). ), The reliability of the electrical connection between the terminal electrode 5 and the internal conductor pattern 3 is greatly improved because the terminal electrode 5 is connected to the terminal electrode conductor film 53.

In addition, a plurality of conductor layers 52 are formed in the recess 51 of one terminal electrode 5, and, for example, a certain conductor layer 52 is formed so that a substantially central portion of a cylindrical shape of the conductor layer 52 crosses the inner wall surface of the recess 51. Position, and a certain conductor layer 52 is formed at a position where a small arc-shaped notch is formed in a part thereof by the inner wall surface of the concave portion 51, and further, a certain conductor layer 52 is formed. The inner wall surface of the concave portion 51 is formed at a position where a large arc-shaped notch is formed in a part thereof.

That is, in one land electrode pattern 55,
A plurality of conductor layers 52 are arranged on different circumferences.

Thus, even if the formation position of the concave portion 51 is slightly displaced during the manufacturing process, or if the formation position of the conductive layer 52 is slightly displaced, at least one conductive layer 52 is surely removed from the inner wall surface of the concave portion 51. Can be exposed, and very high connection reliability can be maintained.

Next, the method for manufacturing a laminated circuit board according to the present invention will be described, focusing particularly on the portion where the terminal electrode 5 is formed.
In the description, the manufacturing method using the large-sized green sheet laminating method will be described, and in particular, the plan view of the green sheet 10c that becomes the insulating layer 1c in the laminated body 1 of FIG. 1 will be described.

First, a large ceramic (or glass ceramic) green sheet to be used as the insulating layers 1a to 1e is prepared.

Next, a through-hole serving as a via-hole conductor for forming a normal circuit network is formed in each green sheet by NC punching. In the green sheet 10c shown in FIG. 4A, reference numeral 40 denotes a through hole serving as a via hole conductor 4 forming a circuit network, and reference numeral 56 denotes a through hole serving as a conductor layer 52 of the terminal electrode 5 portion. The diameter of the through hole 56 is, for example, 0.15 to 0.3 mm, and the boundary portion is indicated by a dotted line x.
Indicated by

Next, a conductor is filled into the through holes by printing and filling a predetermined conductive paste into the through holes of each green sheet, and a conductor film including an internal conductor pattern including a land electrode pattern is formed on each green sheet. Form. In the green sheet 10c shown in FIG.
The conductor filled in the through hole 56 is denoted by 4 ', the conductor filled in the through hole 56 is denoted by 52', the conductor film serving as the land electrode pattern 55 is denoted by 55 ', and the conductor film serving as the internal conductor pattern 3 is denoted by 3'. I have. By this step, the conductor film 3 ′ serving as the internal conductor pattern 3 formed on each green sheet is made up of the conductor film 55 ′ serving as the land electrode pattern 55, the conductor 4 ′ serving as the via hole conductor 4, and the conductor 52 serving as the conductor layer 52 Are integrally formed, and their connection reliability is greatly improved.

Next, a punched hole serving as the concave portion 51 serving as the terminal electrode 5 is formed. In FIG. 4C, this punched hole is indicated by 50. The punched hole 50 has a boundary line x
Conductor film 5 that straddles and becomes the land electrode pattern 55
5 ′ and a part of the conductor of the conductor layer 52 are formed by punching holes 50.
It is formed so as to be exposed from the inner surface.

The opening diameter of the punched hole 50 is, for example, approximately 0.4 to 2.0 mm.

As described above, it is desirable that the conductors that become the plurality of conductor layers 52 be formed in a zigzag pattern on the line that is the outer periphery of the processing hole 50. Thereby, the conductor layer 52
Are buried in the inner wall surface of the processing hole 50.

Next, a conductive film to be the terminal electrode conductive film 53 is applied to the inner wall surface of the punched hole of each green sheet by printing a conductive paste. Specifically, application of the conductive paste to the inner wall surface of the processing hole 50 can be easily formed by its own weight. When printing the conductor film to be the terminal electrode conductor film 53, the plate making of a printable area slightly larger than the opening is used, so that the formation of the land electrode pattern 55 can be omitted. In forming the conductor film to be the terminal electrode conductor film 53, printing is performed from both main surfaces of the green sheet.
A conductor film is formed around the opening also on one main surface side on which the internal conductor pattern 3 is formed. Therefore, when the green sheets are stacked, electrical connection with the conductor film serving as the land electrode pattern 55 on one main surface side of the adjacent green sheet can be reliably performed.

Next, the insulating layer 1a to the conductor layer serving as the via hole conductor 4, the conductor layer 52, the internal conductor pattern 3, the land electrode pattern 55, and the terminal electrode conductor film 53 are formed. The green sheets to be 1e are laminated and pressure-bonded and integrated to form an unfired large-sized laminate.

As for the green sheets of the insulating layers 1e and 1e as the outermost layers, a conductor film as the surface conductor pattern 2 may be formed as necessary instead of the conductor film as the internal conductor pattern 3. Absent.

Next, according to the shape of each circuit board, a division groove is formed or the large unfired laminate is cut or cut. For example, by cutting, the processing hole 50 is divided into two and becomes the concave portion 51 of the terminal electrode 5.

Next, a firing process is performed on the unfired laminate. As a result, a laminate 1 having the conductor layer 52, the land electrode pattern 55, and the terminal electrode conductor film 53 in the terminal electrode 5 portion, and having the via hole conductor 4, the internal conductor pattern 3, and the surface conductor pattern 2 is achieved. FIG. 4D shows the surface state of the insulating layer 1c in this state.

After that, if necessary, the surface conductor pattern 2 is formed by printing and baking a conductive paste, and when the dividing grooves are formed in the above-described steps, a dividing process is performed on the shape of each circuit board. The surface of the terminal electrode conductor film 53 of the body 1 is plated to form a surface plating layer 54, and the electronic component 6 is mounted on the surface conductor pattern 2. Thereby, the laminate 1 shown in FIG. 1 is completed.

According to the manufacturing method of the present invention, the conductor to be the conductor layer 52 is divided or cut in the thickness direction of the laminate so that the conductor is completely exposed or partially exposed to the through hole 55 that becomes the recess 51. Further, a terminal electrode conductor film 53 is formed on the inner wall surface of the concave portion 51. Therefore, as described above, the connection between the terminal electrode conductor film 53 and the internal conductor pattern 3 including the land electrode pattern 55 is made in the thickness direction of the conductor layer 52, so that the connection reliability is improved.

Also, even if printing misalignment of the conductor film on the green sheet, sheet lamination misalignment, or formation misalignment of the through-hole, which cannot be avoided in the method of manufacturing the laminated circuit board 10, occurs, the conductor layer 52 remains , Each insulating layer 1a-1
Since the terminal electrode 5 is connected to the land electrode pattern 55, the open state due to the lamination of the terminal conductor conductor film 53 of the terminal electrode 5 can be avoided, and the connection reliability is greatly improved.

In the above-described manufacturing method, the processing hole 50 which becomes the concave portion 51 of the terminal electrode 5 is formed in each green sheet, but the green sheets on which the conductor layer 52 and the land electrode pattern 55 are formed are laminated. After integration, the insulating layer 1
A processing hole 50 which becomes the concave portion 51 of the terminal electrode 5 is formed in a lump of the green sheet laminates a to 1e.
The conductor film serving as the terminal electrode conductor film 53 may be formed by applying a conductive paste.

In the above-described manufacturing method, the green sheet is formed by a multilayer method. However, a laminate may be formed by printing multiple layers of a conductive paste and an insulating paste.

In the above description, the laminated circuit board 10 in which five insulating layers are stacked has been described. However, the total number of insulating layers can be changed arbitrarily. Materials can also be changed arbitrarily. Further, the shape of the via hole conductor and the shape of the through hole can be arbitrarily changed.

[0059]

According to the present invention, the via-hole conductor exposed on the inner wall surface is formed on the inner wall surface of the concave portion of the terminal electrode. As a result, the connection reliability between the terminal electrode and the internal conductor pattern is improved by adding the connection in the thickness direction of the laminate to the connection between the terminal electrode and the internal conductor pattern in addition to the conventional planar connection. Improve dramatically.

[Brief description of the drawings]

FIG. 1 is a perspective view of a laminated circuit board according to the present invention.

FIG. 2 is a sectional view taken along line AA of the laminated circuit board of the present invention.

FIG. 3 is a perspective view of the laminated circuit board of the present invention in which a terminal electrode conductor film in a terminal electrode portion is omitted.

FIGS. 4A to 4D are partial plan views illustrating a method for manufacturing a laminated circuit board according to the present invention.

[Explanation of symbols]

 10 Circuit board 1 Laminated body 1a-1e Insulating layer 2 Surface conductor pattern 3 Internal conductor pattern 4 Via-hole conductor 5 Terminal electrode 51 ... concave part 52 ... via hole conductor 53 ... terminal electrode conductor film 54 ... plating layer 55 ... land electrode pattern

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 5E317 AA01 AA07 AA22 AA24 BB12 BB13 BB14 BB15 BB16 BB17 BB18 CC05 CC15 CC31 CD27 CD32 5E346 AA42 AA43 BB11 CC16 CC32 CC35 CC36 CC39 CC40 DD22 EE29 FF04 FF07 FF19 FF10 FF07 FF10 HH22

Claims (1)

[Claims] 1. A concave portion for a terminal electrode penetrating in a thickness direction of the laminated body is formed on an end surface of a laminated body formed by laminating an insulating layer and an internal wiring layer, and the internal wiring is formed on an inner wall surface of the concave portion. A laminated circuit board, wherein a conductor layer connected to a layer and extending in a thickness direction is buried so as to partially expose the terminal layer, and a terminal electrode conductor film is formed on the inner wall surface of the concave portion.