Joining material for electronic components electronic...

Details Joining material for electronic components electronic... Joining material for electronic components electronic...

1999-02-24

2002-04-23

Jones, Deborah (Department: 1775)

Stock material or miscellaneous articles

Composite

Of quartz or glass

C428S693100, C428S699000, C428S701000, C428S702000, C501S032000, C501S138000

Reexamination Certificate

active

06376085

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Technical Field
The invention relates to a joining material for an electronic component, such as capacitors, inductors, resistors, stacked type and coaxial type dielectric filters, stacked type LC filters, composite LC components and composite LCR modules, an electronic component and a method for manufacturing same.
2. Related Arts
When manufacturing a stacked type dielectric filter, a paste for an internal layer electrode is printed on each of a predetermined number of greensheets, which are then laminated to produce laminated greensheets. These laminated greensheets are then sintered at a temperature of 700° C. to 1100° C. to produce a base body with the internal layer electrodes. After the base body is polished, a metal paste for an outer electrode is printed on predetermined regions on the surface of the body and fired to form the outer electrodes. A composite LC filter with an inductor and capacitor is also known.
When producing such composite electronic components, a predetermined number of greensheets for, for example, a dielectric layer and magnetic layer are laminated to provide laminated greensheets, which are then co-fired to join the magnetic and dielectric layers. It is also known to provide a greensheet of a joining layer between the greensheets of the magnetic and dielectric layers to provide laminated greensheets which are then co-fired. In Japanese publication Tokkohei 120605/1995, a ceramic material, obtained by firing a mixture of ZnO, TiO
2
, an CuO, is used for the joining layer for preventing peeling between the dielectric layers and magnetic layers and diffusion of the ingredients of both layers with each other. In Japanese patent application publication Tokkaihei 36913/1997, a ceramic material is provided between the dielectric and magnetic layers for improving the adhesive strength of the layers and for preventing diffusion of the ingredients of both layers with each other, the ceramic material being obtained by mixing a glass contained in the dielectric layer with a ceramic of 15 to 40 mol % of BaO and 60 to 85 mol % of TiO
2
and firing.
SUMMARY OF THE INVENTION
However, according to the inventor's research, warp may occur in the magnetic or dielectric layer depending on the compositions of both layers and their firing schedule. When the amount of warp is out of the specification for manufacturing a filter, such filter with impermissible warp is discarded as being defective, thus decreasing its manufacturing yield. The inventors further found that warp was also induced in the layers during the sintering process.
The object of the invention is, in an electronic component having a plurality of functional layers each selected from a magnetic layer and dielectric layer and joined with each other, to prevent warp in the magnetic layers or the dielectric layer.
The invention provides a joining material for an electronic component having a plurality of functional layers each selected from a magnetic layer and dielectric layer, the functional layers being joined with the joining material to each other, the joining material comprising a glass and a composition of a mol % of ZnO, b mol % of BaO and c mol % of TiO
2
(a=12-45, b=4-45, c=18-81, a+b+c=100), wherein 0.1 to 10 weight parts of the glass is added to 100 weight parts of the composition.
The invention also provides a joining material for the electric component, the joining material comprising a glass and a composition of a mol % of ZnO, b mol % of BaO, c mol % of TiO
2
and d mol % of MnO (a=12-45, b=4-45, c=18-81, d≦10, a+b+c+d=100), wherein 0.1 to 10 weight parts of the glass is added to 100 weight parts of the composition.
The invention also provides a joining material for the electric component, the joining material comprising a glass and a composition of a mol % of ZnO, b mol % of BaO, c mol % of TiO
2
and e mol % of Al
2
O
3
(a=12-45, b=4-45, c=18-81, e≦10, a+b+c+e=100), wherein 0.1 to 10 weight parts of the glass is added to 100 weight parts of the composition.
The invention also provides a joining material for the electric component, the joining material comprising a glass and a composition of a mol % of ZnO, b mol % of BaO, c mol % of TiO
2
, d mol % of MnO and e mol % of Al
2
O
3
(a=12-45, b=4-45, c=18-81, d≦10, e≦10, a+b+c+d+e=100), wherein 0.1 to 10 weight parts of the glass is added to 100 weight parts of the composition.
The invention also provides an electronic component having the functional layers and a joining layer for joining the adjacent functional layers, wherein the joining layer is composed of a sintered product of each of the joining materials. That is, a layer composed of each of the joining materials is fired to form the joining layer. The joining layer is made of the sintered product obtained by firing the joining material.
The invention also provides an electronic component having the functional layers and a joining layer, wherein the joining layer is composed of sintered product showing at least one of a peak corresponding to BaNd
2
Ti
5
O
14
and a peak corresponding to BaNd
2
Ti
4
O
12
when measured by means of powdery X-ray diffraction method.
The invention also provides a method for manufacturing an electronic component having the functional layers and a joining layer, the method comprising the steps of:
laminating the functional layers already sintered to provide a laminated body, wherein a layer made of each of the joining materials is provided, and
firing the joining material to form the joining layer.
The invention also provides a method for manufacturing an electronic component having the functional layers and a joining layer, the method comprising the steps of:
laminating greensheets, for the functional layers, to provide laminated greensheets, wherein a layer made of each of the joining materials is provided, and
firing the laminated greensheets with the layer made of the joining material to form the functional layers and the joining layer.
The inventors researched the above described warp of a dielectric layer or magnetic layer and finally made the following discovery. According to state-of-the-art knowledge, it is possible to improve the adhesive strength and therefore to prevent the peeling of the magnetic and dielectric layers, by adjusting the thermal expansion coefficient of joining ceramics between the magnetic and dielectric layers to those of both layers.
However, in actual manufacturing, depending on the selection of materials for the magnetic and dielectric layers and sintering schedule, even when the thermal coefficient of the joining ceramics is adjusted to those of the magnetic and dielectric layers, warp may be observed during the sintering process. This phenomenon probably means that the magnetic, dielectric and joining layers shrink at different firing shrinkage rates at certain or even almost any time point during the sintering.
The inventors, based on the above discovery, successfully provide a solution. That is, the above warp may be considerably decreased or even prevented, on a wide variety of materials for magnetic and dielectric layers, by providing a joining material according to the above specific compositions.
In the above compositions, for further reducing the warp of the magnetic or dielectric layer, a content of ZnO (a mol %) may preferably be 25 to 40 mol %, a content of BaO (b mol %) may preferably be 5 to 15 mol %, and a content of TiO
2
(c mol %) may preferably be 45 to 65 mol %.
A glass contained in the inventive joining material may preferably be selected from a group consisting of ZnO—SiO
2
—B
2
O
3
glass, PbO—B
2
O
3
—SiO
2
glass, Al
2
O
3
—CaO—B
2
O
3
—SiO
2
glass, B
2
O
3
—SiO
2
glass, MgO—Al
2
O
3
—SiO
2
cordierite glass, and ZnO—MgO—Al
2
O
3
—SiO
2
cordierite glass, and most preferably be ZnO—SiO
2
—B
2
O
3
glass. These glasses may further contain TiO
2
, ZrO
2
or Y
2
O
3
.
The greensheets f

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