Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package – Outside periphery of package having specified shape or...
Reexamination Certificate
2001-05-23
2003-06-10
Lebentritt, Michael S. (Department: 2824)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
Outside periphery of package having specified shape or...
C257S638000
Reexamination Certificate
active
06576999
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electronic component, a manufacturing method thereof, an aggregate electronic component, a mounting structure of an electronic component, and an electronic device, and more particularly, the present invention relates to an improvement in the formation and structure of an external terminal electrode.
2. Description of the Related Art
A prior art which is related to the present invention is disclosed in Japanese Unexamined Patent Application Publication No. 08-37251. Hereinafter, this is referred to as the “first prior art”.
This first prior art relates to a laminated electronic component and a manufacturing method therefor. The first prior art is characterized in that first, an aggregate electronic component is produced, and then, a plurality of electronic components are produced from the aggregate electronic component by dividing the aggregate electronic component along dividing lines.
More specifically, a laminated body is produced by laminating a plurality of dielectric sheets having via-hole conductors formed therein, then through-holes passing through the laminated body are formed at locations of the via-hole conductors, thereby the via-hole conductors are divided, and a portion of each of the via-hole conductors is caused to be exposed to the inner surface of the through-hole. Next, by dividing the laminated body along dividing lines passing through the through-holes, electronic components are removed and produced such that each of the electronic components has external terminal electrodes each constituted of a portion of the via-hole conductor.
In accordance with the first prior art, external terminal electrodes can be easily formed even if the arrangement pitch is fine, and the characteristics of the individual electronic components which exist at the stage of a laminated body when it is in the state of an aggregate electronic component, can be measured.
Another prior art which is related to the present invention is disclosed in Japanese Unexamined Patent Application Publication No. 06-96992. Hereinafter, this is referred to as the “second prior art”.
This second prior art also relates to a laminated electronic component and a manufacturing method therefor. As in the case of the first prior art, the second prior art is characterized in that firstly an aggregate electronic component is produced, and that a plurality of electronic components is removed from the aggregate electronic component by dividing the aggregate electronic component along dividing lines.
More specifically, a laminated body is produced by laminating a first dielectric sheet which has via-hole conductors defining external terminal electrodes formed therein, and a second dielectric sheet which does not via-hole conductors formed therein, then grooves are formed so as to divide the via-hole conductors, and thereby a portion of each of the via-hole conductors is caused to be exposed to the inner surface of the groove. Next, by dividing the laminated body along the grooves, electronic components are produced such that each of the electronic components are provided with external terminal electrodes each constituted of a portion of the via-hole conductor.
In accordance with the second prior art, as in the case of the first prior art, external terminal electrodes can be easily formed even if the arrangement pitch is fine, and measurement of the characteristics of the individual electronic components can be measured at the stage of a laminated body in the state of an aggregate electronic component.
In the first prior art, there are provided external terminal electrodes each having a length that is equivalent to that of the through-hole formed in the laminated body. In contrast, in the second prior art, the external terminal electrodes have a length that is within the range of the depth of each of the grooves, the depth of each of the grooves corresponding to a portion of the thickness of the laminated body.
However, each of the first and second prior arts presents problems to be solved.
First, in the first prior art, since each of the external terminal electrodes has a length that is equivalent to that of each of the through-holes formed in the laminated body, the external terminal electrodes are arranged so as to reach both of first and second main surface. Therefore, for example, when using the first main surface as a mounting surface for mounting components, a predetermined space must be provided between external terminal electrodes and connection terminals for the mounted components when soldering the mounded component, in order to prevent short circuits between the mounted components and the external terminal electrodes. This greatly reduces the area in which mounted components can be mounted.
Likewise, in the case where this electronic component is mounted on a mother circuit board, when the second main surface is arranged to face the mother circuit board, it is necessary to prevent solder or other such connecting material used for connecting external terminal electrodes and the mother circuit board from causing an undesirable electrical short circuit between wiring conductors and the external terminal electrodes on the second main surface. For this purpose, a predetermined space must be provided between the wiring conductors and the external terminal electrodes. This also leads to a reduction in the mountable area for wiring conductors on the second main surface.
Furthermore, when the electronic component is a ceramic electronic component that is manufactured through a firing process, irregularities or uneven portions occur in the vicinity of external terminal electrodes on the main surfaces of the electronic component due to a difference in the shrinkage during firing between the via-hole conductors and the ceramic. As a result, when wire-bonding mounting or flip-chip mounting is performed, each of which is usually required to provide a coplanarity of not more than 20 &mgr;m, it is impossible to properly perform mounting in the vicinity of the external terminal electrodes. This also causes a reduction in the mountable area for mounted components.
When an electronic component is mounted on a mother circuit board via solder, solder fillets are formed between the external terminal electrodes of the electronic component and the connection terminals of the mother circuit board. When the electronic component is used for a high-frequency application, these solder fillets function as inductance components which cannot be ignored, and hence, the control over the height of fillets is important. The height of the fillet is determined by the amount of solder used and the wettability of the solder with respect to the surface of the external terminal electrodes. However, if the external terminal electrodes are provided so as to pass through in the thickness direction of the electronic component, the height of fillets will be difficult to control, and hence, when the electronic component is used for a high-frequency application, the inductance component due to solder fillets varies.
The above-described problems which are experienced with the first prior art can be solved to some extent by using the method of the second prior art. This is because, in accordance with the second prior art, the external terminal electrode is not arranged so as to pass through in the thickness direction of the electronic component, but is arranged so as to reach only one of the main surfaces.
However, the second prior art has the following problem.
Even at the stage of a laminated body in the state of an aggregate electronic component, in order to allow characteristics of individual electronic components to be measured, external terminal electrodes for the individual electronic components are made to be independent of one another by dividing the via-hole conductors. Such division of the via-hole conductors is achieved by forming grooves along dividing lines for dividing via-hole conductors so as to remove and separate the individual electronic compo
Iida Kazuhiro
Sakai Norio
Keating & Bennett LLP
Lebentritt Michael S.
Murata Manufacturing Co. Ltd.
Smith Brad
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