Electrical generator or motor structure – Non-dynamoelectric – Piezoelectric elements and devices
Reexamination Certificate
1999-10-18
2002-06-11
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Non-dynamoelectric
Piezoelectric elements and devices
C310S348000
Reexamination Certificate
active
06404100
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a surface acoustic wave apparatus constructed by sealing a chip-shaped surface acoustic wave element into a package and a method of manufacturing the surface acoustic wave device.
As is generally known, the face-down bonding technique has been put to practical use as one of the techniques for putting various chip-shaped electronic part elements, including semiconductor elements, into a package or the like.
The face-down bonding technique is a packaging technique where the connection terminals provided on a package are connected to the connection terminals of an electrode pattern provided on one surface of the chip element by means of conductive bumps. The term face-down bonding comes from the fact that the surface on which the electrode pattern of the chip element has been formed is caused to face the package.
A surface acoustic wave apparatus, which is constructed by applying the face-down bonding technique to surface acoustic wave elements of chip-shaped electronic part elements, has been available in various configurations shown in
FIGS. 4
to
7
.
FIG. 4
shows a configuration where the electrode pattern
3
a
of a surface acoustic wave element
3
is face-down bonded to the mounting surface
1
a
of the concave-shaped base
1
via conductive bumps
2
and then a flat-plate-like cap
4
is put on the base
1
.
FIG. 5
shows a configuration where the electrode pattern
3
a
of a surface acoustic wave element
3
is face-down bonded to the mounting surface
1
a
of the concave-shaped base
1
via conductive bumps
2
and then a concave-shaped cap
4
is put on the base
1
.
FIG. 6
shows a configuration where the electrode pattern
3
a
of a surface acoustic wave element
3
is face-down bonded to the mounting surface
1
a
of the flat-plate-like base
1
via conductive bumps
2
and then a concave-shaped cap
4
is put on the base
1
.
FIG. 7
shows a configuration where the electrode pattern
3
a
of a surface acoustic wave element
3
is face-down bonded to the mounting surface
1
a
of the flat-plate-like base
1
via conductive bumps
2
and then the surface acoustic wave element
3
is resin-sealed with a cap
4
made of mold resin.
In recent years, surface acoustic wave apparatuses, particularly mobile radio communication filters, have been required to have a low-loss, high-attenuation frequency characteristic. Additionally, as the apparatuses have been getting smaller, the filter parts have also been required to decrease in size.
In addition to this, for example, in cellular phones or the like, a very large number of parts have been used and each part has been required to keep a high quality level. They have particularly been required to have a high reliability under the mechanical stress of impact, falling, vibration, or the like, or the thermal stress of temperature changes (widening the using temperature range).
However, with the configurations of the conventional surface acoustic wave apparatuses shown in
FIGS. 4 and 5
, since the surface acoustic wave element
3
is housed inside the concave-shaped base
1
and the top surface of the surface acoustic wave element
1
is located lower than the top surface of the base
1
, this causes the following problems.
First, in a die shear strength test by which the junction of the conductive bumps
2
is checked by pressing the surface acoustic wave element
3
sideways along the mounting surface
1
a
of the base
1
, the clearance between the side face of the surface acoustic wave element
3
and the inner wall surface of the base
1
is so narrow that it is difficult to insert a test jig for pressing the surface acoustic wave element
3
into the clearance, which makes the examination difficult.
Furthermore, when the surface acoustic wave element
3
is removed from the base
1
and fault analysis is performed, the clearance between the side face of the surface acoustic wave element
3
and the inner wall surface is so narrow that it is difficult to insert tweezers for taking out the surface acoustic wave element
3
into the clearance, which makes it difficult to take the surface acoustic wave element
3
out of the base
1
. This makes the fault analysis difficult.
Additionally, when the surface acoustic wave element
3
is mounted on the base
1
, the sucker of a collect is caused to adhere to the surface acoustic wave element
3
by suction and the element
3
is inserted into the base
1
. Because the sucker of the collect also needs to go into the inside of the base
1
when the surface acoustic wave element
3
is inserted into the inside of the base
1
, only the sucker of the collect narrower than the inner length, or width, of the base
1
can be used.
In the examination, measurement, or fault analysis described above, because only the sucker of the collect narrower than the inner length, or width, of the base
1
can be used, excessive force can be exerted on the surface acoustic wave element
3
, which is therefore liable to break.
Since the conventional surface acoustic wave apparatus shown in
FIG. 6
uses the flat-plate-like base
1
, the following problems arise: when the base
1
is joined to the cap
4
with solder or adhesive, the solder or adhesive squeezed from between the base
1
and the cap
4
is liable to flow toward the conductive bumps
2
.
Furthermore, since the mounting surface
1
a
to which the conductive bumps
2
are connected and metallize are formed on the same surface of the flat-plate-like base
1
, the flatness of the metallize joined to the cap
4
is degraded, which causes a hermetic sealing problem. In addition, because the base
1
takes the form of a flat plate, alignment is difficult when the base is jointed to the cap
4
.
The conventional surface acoustic wave apparatus shown in
FIG. 7
has not only the problem caused by the configuration of the surface acoustic wave apparatus of
FIG. 6
but also an aging problem. Specifically, since the stress of mold resin is exerted on the surface acoustic wave element
3
, the stress makes the surface acoustic wave element
3
liable to age.
BRIEF SUMMARY OF THE INVENTION
It is, accordingly, an object of the present invention to overcome the above problems by providing not only a high-quality surface acoustic wave apparatus which enables a surface acoustic wave element mounted on the base to be subjected easily to such processes as examination, measurement, and fault analysis, but also a method of manufacturing the same.
A surface acoustic wave apparatus according to the present invention comprises a surface acoustic wave element, a base having a mounting surface on which the surface acoustic wave element is mounted and a side wall surrounding the surface acoustic wave element, and a cap so joined to the base that it covers the surface acoustic wave element, wherein the side wall of the base is formed lower than the highest part of the surface acoustic wave element.
With the above configuration, because the side wall of the base is formed lower than the highest part of the surface acoustic wave element mounted on the mounting surface, that is, because the highest part of the surface acoustic wave element mounted on the mounting surface is raised above the side wall of the base, the surface acoustic wave element mounted on the base can be subjected easily to, for example, examination, measurement, fault analysis, and others. Therefore, it is possible to provide a high-quality surface acoustic wave apparatus.
The base is composed of an almost flat-plate-like base body with a mounting surface on which the surface acoustic wave element is mounted and a frame member so provided on the mounting surface of the base body that it surrounds the surface acoustic wave element. The height of the side wall can be set easily by selecting the frame member.
The frame member is constructed by stacking plural frame member layers. The height of the wall surface can be set easily by selecting the number of frame member layers or a combination of frame member layers differing in thickness.
The cap is
Chujo Rieko
Koshino Masayoshi
Sakinada Kaoru
Addison Karen
Ramirez Nestor
LandOfFree
Surface acoustic wave apparatus and method of manufacturing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Surface acoustic wave apparatus and method of manufacturing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Surface acoustic wave apparatus and method of manufacturing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2979884