Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package – With contact or lead
Reexamination Certificate
2002-10-01
2003-10-28
Clark, Jasmine (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
With contact or lead
C257S678000, C257S703000, C257S704000, C257S705000
Reexamination Certificate
active
06639311
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a multilayer ceramic electronic component and a method for producing the same, and an electronic component aggregate which is produced during a process for producing the multilayer ceramic electronic component. More particularly, the present invention relates to an improvement in a structure for mounting a cover on the body of a multilayer ceramic electronic component including the cover.
2. Description of the Related Art
Various types of multilayer ceramic electronic components which are of interest with regard to the present invention are shown in
FIGS. 14 and 15
.
A multilayer ceramic electronic component
1
shown in
FIG. 14
includes an electronic component body
2
, with external terminal electrodes
3
being disposed at side surfaces of the electronic component body
2
. The electronic component body
2
has a structure in which a plurality of ceramic layers are stacked. Although a conductive film and a via hole conductor are provided as internal circuit conductors inside the electronic component body
2
, these are not shown in FIG.
14
.
When the multilayer ceramic electronic component
1
is mounted onto a wiring substrate
4
, the external terminal electrodes
3
are connected to connection lands
5
, disposed on the wiring substrate
4
, through solder
6
. Here, since the external terminal electrodes
3
are disposed on side surfaces of the electronic component body
2
, the solder
6
forms a solder fillet.
A multilayer ceramic electronic component
11
shown in
FIG. 15
includes an electronic component body
12
, with external terminal electrodes
14
being disposed on a downwardly facing major surface
13
of the electronic component body
12
. The electronic component body
12
has a structure in which a plurality of ceramic layers
15
are stacked, and an internal circuit conductive film
16
and an internal circuit via hole conductor
17
are provided as internal circuit conductors inside the electronic component body
12
.
The external terminal electrodes
14
are called LGA (land grid array) type electrodes. When an attempt is made to mount the multilayer ceramic electronic component
11
onto the wiring substrate
4
, the external terminal electrodes
14
are arranged so as to oppose connection lands
5
on the wiring substrate
4
, and the external terminal electrodes
14
and the connection lands
5
are connected together through solder
18
. In soldering using the solder
18
, ordinarily, cream solder is printed onto the connection lands
5
, and, then, the multilayer ceramic electronic component
11
is placed onto the wiring substrate
4
in order to carry out reflow soldering using the cream solder. Unlike the multilayer ceramic electronic component
1
having the external terminal electrodes
3
disposed on side surfaces of the electronic component body
2
shown in
FIG. 14
, the multilayer ceramic electronic component
11
including the LGA-type external terminal electrodes
14
shown in
FIG. 15
is such that the planar dimensions of the multilayer ceramic electronic component
11
itself becomes a planar dimensions that is required for mounting because the solder
18
does not form a solder fillet. Consequently, the planar dimensions required for mounting can be made small, so that higher density mounting can be achieved.
Electronic components which cannot be incorporated inside the electronic component body
2
of such a multilayer ceramic electronic component
1
or the electronic component body
12
of such a multilayer ceramic electronic component
11
, such as inductors, capacitors, resistors, transistors, diodes, or integrated circuits, are sometimes mounted onto an upwardly facing major surface of the electronic component body
2
or the electronic component body
12
. In
FIG. 14
, these components that are mounted are not shown. In
FIG. 15
, a number of components
20
that are mounted are shown on an upwardly facing major surface
19
of the electronic component body
12
.
When such components
20
are mounted, for the purpose of, for example, causing the multilayer ceramic electronic component
1
or the multilayer ceramic electronic component
11
to be in a surface mountable state, a cover
7
(indicated by broken lines in
FIG. 14
) or a cover
21
(indicated by broken lines in
FIG. 15
) is joined to the electronic component body
2
or the electronic component body
12
corresponding thereto. The covers
7
and
21
are like receptacles, and are arranged so that their openings face their corresponding electronic component bodies
2
and
12
.
In the case of the multilayer ceramic electronic component
1
shown in
FIG. 14
, when the cover
7
is made of metal, it can be secured to the electronic component body
2
by, for example, soldering and joining it to either one of the external terminal electrodes
3
.
In contrast, in the multilayer ceramic electronic component
11
shown in
FIG. 15
, since the external terminal electrodes are not disposed on side surfaces of the electronic component body
12
, the cover
21
cannot be easily mounted as the cover
7
can in the multilayer ceramic electronic component
1
described above.
For example, when an attempt is made to mount the cover
21
using the downwardly facing external terminal electrodes
14
mounted to the electronic component body
12
, the planar configuration of the multilayer ceramic electronic component
11
becomes larger than the planar size of the electronic component body
12
by an amount corresponding to the thickness of the cover
21
and a joining portion to the external terminal electrodes
14
, thereby preventing size reduction of the multilayer ceramic electronic component
11
.
There is a method illustrated in FIG.
16
. In this method, joining electrodes
22
are disposed on the upwardly facing major surface
19
of the electronic component body
12
, end portions
23
defining the opening of the cover
21
are bent inward so as to oppose the joining electrodes
22
, and the end portions
23
are soldered to the joining electrodes
22
using solder
24
.
However, when such a method described above is used, since the area for mounting the components
20
onto the major surface
19
of the electronic component body
12
becomes small, in order to cause this mounting area to be equal to or greater than a certain area, the multilayer ceramic electronic component
11
must be made rather large.
When the cover
21
is made of metal, the area of the bent end portions
23
cannot be made so small due to processing problems. In addition, in order to provide the required adhesive strength between the joining electrodes
22
and the end portions
23
, the areas of the joining electrodes
22
and the areas of the end portions
23
cannot be made so small. Therefore, regardless of the planar size of the electronic component body
12
, the areas of the joining electrodes
22
and the areas of the end portions
23
need to be equal to or greater than certain areas. The smaller the planar configuration of the electronic component body
22
, the more noticeable the problem concerning restrictions on the area for mounting the aforementioned components
20
becomes.
On the other hand, an electrode shown in
FIG. 17
has been proposed as an electrode disposed on a side surface of an electronic component body of a multilayer ceramic electronic component.
FIG. 17
is a perspective view showing in enlarged form a portion of an electronic component body
26
of a multilayer ceramic electronic component
25
. A notch
28
which vertically passes through the electronic component body
26
is disposed in a side surface
27
of the electronic component body
26
. An electrode
29
is arranged so as to cover the inside surface defining the notch
28
.
The aforementioned electrode
29
may, for example, be formed by a method such as the following.
Basically, in this method, after forming an electronic component aggregate from which a plurality of the electronic component bodies
26
are obt
Kato Isao
Nishide Mitsuyoshi
Sakai Norio
Clark Jasmine
Keating & Bennett LLP
Murata Manufacturing Co. Ltd.
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