U.S. patent application number 11/567593 was filed with the patent office on 2008-03-20 for surface mounted electronic component.
This patent application is currently assigned to FOXCONN ADVANCED TECHNOLOGY INC.. Invention is credited to WEN-CHIN LEE, CHENG-HSIEN LIN.
Application Number | 20080070429 11/567593 |
Document ID | / |
Family ID | 39135340 |
Filed Date | 2008-03-20 |
United States Patent
Application |
20080070429 |
Kind Code |
A1 |
LEE; WEN-CHIN ; et
al. |
March 20, 2008 |
SURFACE MOUNTED ELECTRONIC COMPONENT
Abstract
An exemplary surface mounted electronic component has block body
including a bottom soldering surface, a top surface and a
peripheral wall having a first peripheral wall portion and a second
peripheral wall portion. The bottom soldering surface defines a
first soldering area and a second soldering area. The first
peripheral wall portion adjoins the first soldering area and has at
least a first cutout defined between the first peripheral wall
portion and the first soldering area. The second peripheral wall
portion adjoins the second soldering area and has at least a second
cutout defined between the second peripheral wall portion and the
second soldering area. When the surface mounted electronic
component is soldered, the melting solder can climb up the cutouts
of the sidewall due to capillary effect and `chimney effect`,
thereby avoiding `tombstoning`.
Inventors: |
LEE; WEN-CHIN; (Tayuan,
TW) ; LIN; CHENG-HSIEN; (Tayuan, TW) |
Correspondence
Address: |
PCE INDUSTRY, INC.;ATT. CHENG-JU CHIANG JEFFREY T. KNAPP
458 E. LAMBERT ROAD
FULLERTON
CA
92835
US
|
Assignee: |
FOXCONN ADVANCED TECHNOLOGY
INC.
Tayuan
TW
|
Family ID: |
39135340 |
Appl. No.: |
11/567593 |
Filed: |
December 6, 2006 |
Current U.S.
Class: |
439/83 |
Current CPC
Class: |
Y02P 70/613 20151101;
Y02P 70/50 20151101; H05K 2201/10727 20130101; Y02P 70/611
20151101; H05K 3/3442 20130101; H05K 2201/09181 20130101; H05K
2201/10636 20130101 |
Class at
Publication: |
439/83 |
International
Class: |
H05K 1/00 20060101
H05K001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 15, 2006 |
CN |
200610062621.8 |
Claims
1. A surface mounted electronic component having a block body,
comprising: a bottom soldering surface comprising a first soldering
area and a second soldering area, a top surface opposite to the
bottom soldering surface, a first peripheral wall portion adjoining
the first soldering area of the bottom soldering surface, the first
peripheral wall portion having at least a first cutout defined
between the first peripheral wall portion and the first soldering
area of the bottom soldering surface the first cutout being so
dimensioned that it will exhibit a capillary effect and a chimney
effect, and a second peripheral wall portion adjoining the second
soldering area of the bottom soldering surface, the second
peripheral wall portion having at least a second cutout defined
between the second peripheral wall portion and the second soldering
area of the bottom soldering surface the second cutout being so
dimensioned that it will exhibit a capillary effect and a chimney
effect.
2. The surface mounted electronic component as claimed in claim 1,
wherein the first cutout is defined between the first soldering
area of the bottom soldering surface and the top surface so as to
be filled with solder by the capillary effect and the chimney
effect.
3. The surface mounted electronic component as claimed in claim 2,
wherein the second cutout is defined between the second soldering
area of the bottom soldering surface the top surface so as to be
filled with the solder by the capillary effect and the chimney
effect.
4. The surface mounted electronic component as claimed in claim 1,
wherein a cross-section of the first cutout taken normal to the
bottom soldering surface is selected from a group consisting of
arc-shaped, U-shaped, V-shaped, and broken-lines-shaped.
5. The surface mounted electronic component as claimed in claim 4,
wherein a cross-section of the second cutout taken normal to the
bottom soldering surface is selected from a group consisting of
arc-shaped, U-shaped, V-shaped, and broken-lines-shaped.
6. The surface mounted electronic component as claimed in claim 1,
wherein the block body has a configuration of polyhedron.
7. The surface mounted electronic component as claimed in claim 6,
wherein the polyhedron is a rectangular parallelepiped.
8. The surface mounted electronic component as claimed in claim 1,
wherein the block body has a configuration of cylinder.
9. The surface mounted electronic component as claimed in claim 1,
wherein the first soldering area and the second soldering area are
symmetrical.
10. The surface mounted electronic component as claimed in claim 1,
wherein the first cutout extends in a direction perpendicular to
the first soldering area.
11. The surface mounted electronic component as claimed in claim
10, wherein the second cutout extends in a direction perpendicular
to the second soldering area.
12. The surface mounted electronic component as claimed in claim 1,
further comprising a first and a second soldering pads attached on
the first soldering area and the second soldering area
respectively.
Description
TECHNICAL FIELD
[0001] The present invention generally relates to electronic
components, and more particularly relates to a surface mounted
electronic component.
BACKGROUND
[0002] `Tombstoning`, also known as Drawbridge effect or Manhattan
Skyline effect, is considered a common defect in surface mounting
technology. `Tombstoning`, i.e., a phenomenon where electronic
components erect like tombstones, is due to unbalanced surface
tension of two soldered end portions of an electronic component.
Particularly, when a low mass chip-type electronic component is
soldered on a substrate such as a printed circuit board, the
unbalanced surface tension may easily occur and draw one soldered
end portion to the substrate and the other soldered end portion
free, thus causing `tombstoning`.
[0003] Generally, the unbalanced surface tension of two soldered
end portions occurs due to poor soldering pad design, non-uniform
heating of soldering surfaces, low reactivity of solder,
non-uniform application of solder and so on.
[0004] With the current trend toward miniaturization of electronic
devices there is a concomitant trend toward reducing the size of
the electronic components themselves. The reduction in size and
mass of electronic components has been a significant aid in the
miniaturization process but has created problems such as
`tombstoning`. Referring to FIG. 9 and FIG. 10, such a typical
electronic component 10 is prone to tombstoning on a printed
circuit board 12 due to unbalanced surface tension of two soldered
end portions. `Tombstoning` can cause electric connections between
the electronic component and circuits to be broken, resulting in
the electronic component losing its functions and causing a
mounting failure.
[0005] What is needed, therefore, is a surface mounted electronic
component having ability of avoiding `tombstoning`.
SUMMARY
[0006] One preferred embodiment provides a surface mounted
electronic component. The surface mounted electronic component has
a block body. The block body includes a bottom soldering surface, a
top surface opposite to the bottom soldering surface and a
peripheral wall. The bottom soldering surface defines a first
soldering area and a second soldering area. The peripheral wall
includes a first peripheral wall portion and a second peripheral
wall portion. The first peripheral wall portion adjoins the first
soldering area of the bottom soldering surface and has a first
cutout defined between the first peripheral wall portion and the
first soldering area of the bottom soldering surface. The second
peripheral wall portion adjoins the second soldering area of the
bottom soldering surface and has a second cutout defined between
the second peripheral wall portion and the second soldering area of
the bottom soldering surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Many aspects of the present embodiments can be better
understood with reference to the following drawings. The components
in the drawings are not necessarily drawn to scale, the emphasis
instead being placed upon clearly illustrating the principles of
the present embodiments. Moreover, in the drawings, like reference
numerals designate corresponding parts throughout the several
views.
[0008] FIG. 1 is a schematic view of a surface mounted electronic
component according to a first embodiment;
[0009] FIG. 2 is a bottom view of the surface mounted electronic
component according to the first embodiment;
[0010] FIG. 3 is a schematic view of a surface mounted electronic
component according to a second embodiment;
[0011] FIG. 4 is a bottom view of the surface mounted electronic
component according to the second embodiment;
[0012] FIG. 5 is a schematic view of a surface mounted electronic
component according to a third embodiment;
[0013] FIG. 6 is a bottom view of the surface mounted electronic
component according to the third embodiment;
[0014] FIG. 7 is a schematic view of a surface mounted electronic
component according to a fourth embodiment;
[0015] FIG. 8 is a bottom view of the surface mounted electronic
component according to the fourth embodiment;
[0016] FIG. 9 is a schematic view of a typical surface mounted
electronic component; and
[0017] FIG. 10 is a schematic view of `tombstoning` on a typical
surface mounted electronic component.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0018] Embodiments will now be described in detail below and with
reference to the drawings.
[0019] Referring to FIG. 1 and FIG. 2, a surface mounted electronic
component 20 according to a first exemplary embodiment is
shown.
[0020] The surface mounted electronic component 20 has a block body
200. The block body 200 has a polyhedron configuration. In the
embodiment, the block body 200 is a rectangular parallelepiped
having a soldering bottom surface 21, a top surface 22 opposite to
the soldering bottom surface 21 and a peripheral wall 23. The
peripheral wall 23 adjoins the soldering bottom surface 21 and the
top surface 22 simultaneously. The peripheral wall 23 includes a
first peripheral wall portion 231 and a second peripheral wall
portion 232 opposite to the first peripheral wall portion 231, a
third peripheral wall portion 233 and a fourth peripheral wall
portion 234 opposite to the third sidewall section 233. Therefore,
the first peripheral wall portion 231, the second peripheral wall
portion 232, the third peripheral wall portion 233 and the fourth
peripheral wall portion 234 adjoin both the soldering bottom
surface 21 and the top surface 22.
[0021] The soldering bottom surface 21 defines a first soldering
area 211 and a second soldering area 212. The first soldering area
211 adjoins the first peripheral wall portion 231 and the second
soldering area 212 adjoins the second peripheral wall portion 232.
The first soldering area 211 and the second soldering area 212 are
symmetrical.
[0022] A first cutout 24 is defined between the first peripheral
wall portion 231 and the first soldering area 211 of the bottom
soldering surface 21. A second cutout 25 is defined between the
second peripheral wall portion 232 and the second soldering area
212 of the bottom soldering surface 21. Preferably the first cutout
24 should extend in a direction perpendicular to the first
soldering area 211, and the second cutout 25 should extend in a
direction perpendicular to the second soldering area 212.
Alternatively, the first/second cutout could be a through hole or a
blind hole defined in the first/second soldering area of the bottom
soldering surface, and should be considered to be within the scope
of the present invention. Cross-section shape of the first cutout
24 and the second cutout 25 taken normal to the bottom soldering
surface 21 can be selected from the group consisting of arc-shaped,
U-shaped, V-shaped, and broken-lines-shaped. In the embodiment,
cross-section shape of the first cutout 24 taken normal to the
bottom soldering surface is arc-shaped and cross-section shape of
the second cutout 25 taken normal to the bottom soldering surface
is also arc-shaped.
[0023] Additionally, a first soldering pad 213 and a second
soldering pad 214 can be attached on the first soldering area 211
and the second soldering area 212 respectively. The first soldering
pad 213 and the second soldering pad 214 are configured for
facilitating soldering of the surface mounted electronic component
20.
[0024] The surface mounted electronic component 20 can be mounted
by interposing solder between the soldering areas and a circuit
board and melting the solder to provide mechanical and electrical
connections between the surface mounted electronic component 20 and
circuits on the circuit board.
[0025] Capillary effect can occur due to the thin first cutout 24
and the thin second cutout 25 like capillary tubes. Capillary
effect is the ability of a substance to draw a liquid upwards
against the force of gravity. Due to capillary effect the melting
solder on the first soldering area 211 can climb up the first
cutout 24 along the inside wall thereof, and the melting solder on
the second soldering area 212 also can climb up the second cutout
25 along the inside wall thereof. Therefore, the first cutout 24
and the second cutout 25 can be filled with solder, thereby
increasing area the surface mounted electronic component 20
contacting with the solder.
[0026] Whilst melting the solder, temperature of downside portion
of the first cutout 24 adjoining the soldering bottom surface 21 is
higher than temperature of upside portion of the first cutout 24
adjoining the top surface 21, and temperature of downside portion
of the second cutout 25 adjoining the soldering bottom surface 21
is higher than temperature of upside portion of the second cutout
25 adjoining the top surface 21. Temperature difference causes a
`chimney effect`. The `chimney effect` is a tendency of heated air
to rise in a duct or other vertical passage that results from
thermal differences. Thermal differences between the downside
portion and upside portion of the cutouts will result in pressure
differences, because warm air is less dense than cold air. The less
dense warm air in the downside portion will rise because of its
thermal buoyancy, thereby making the melting solder climb up the
first cutout 24 and the second cutout 25 along the inside wall
thereof respectively and fill the first cutout 24 and the second
cutout 25 respectively.
[0027] The solder filled into the first cutout 24 and the second
cutout 25 connect with the solder between the soldering bottom
surface 21 and the circuit board, thereby forming a whole. Thus the
unbalanced surface tension between the first soldering area 211 and
the second soldering area 212 of the surface mounted electronic
component 20 can be balanced, thereby avoiding `tombstoning`. As a
result, the surface mounted electronic component 20 can be mounted
on the circuit board hard.
[0028] Additionally, cutouts can also be defined in the third
peripheral wall portion 233 and the fourth peripheral wall portion
234 respectively. Thus, area the surface mounted electronic
component 20 contacting with the solder can be further increased,
thereby reinforcing mounting of the surface mounted electronic
component 20 on the circuit board.
[0029] Referring to FIG. 3 and FIG. 4, a surface mounted electronic
component 30 according to a second exemplary embodiment is shown.
The surface mounted electronic component 30 is similar to the
surface mounted electronic component 20 in the first exemplary
embodiment except that a first cutout 34 is defined between the
first soldering area 311 of the bottom soldering surface 31 and the
top surface 32 and a second cutout 35 is also defined between the
second soldering area 312 of the bottom soldering surface 31 and
the top surface 32.
[0030] Referring to FIG. 5 and FIG. 6, a surface mounted electronic
component 40 according to a third exemplary embodiment is shown.
The surface mounted electronic component 40 is similar to the
surface mounted electronic component 20 in the first exemplary
embodiment except that a number of first cutouts 44 are defined
between the first peripheral wall portion 431 and the first
soldering area 411 of the bottom soldering surface 41 and a number
of second cutouts 45 are defined between the first peripheral wall
portion 431 and the first soldering area 411 of the bottom
soldering surface 41. When the surface mounted electronic component
40 is soldered, due to capillary effect and the `chimney effect`,
the melting solder on a first soldering area 411 can climb up the
first cutouts 44 along the inside wall thereof, and the melting
solder on a second soldering area 412 can also climb up the second
cutouts 45 along the inside wall thereof. Thus area of the surface
mounted electronic component 40 contacting with the solder can be
further increased, thereby further balancing the surface tension
between the first soldering area 411 and the second soldering area
412 of the surface mounted electronic component 40 and reinforcing
mounting of the surface mounted electronic component 40 on the
circuit board.
[0031] Additionally, the surface mounted electronic component can
have a configuration of any other structure. Referring to FIG. 7
and FIG. 8, a surface electronic component 50 according to a fourth
exemplary embodiment is shown. The surface electronic component 50
has a block body 500. The block body 500 is a cylinder having a
soldering bottom surface 51, a top surface 52 opposite to the
soldering bottom surface 51 and a peripheral wall 53. The
peripheral wall 53 adjoins the soldering bottom surface 21 and the
top surface 22 simultaneously. The peripheral wall 53 includes a
first peripheral wall portion 531 and a second peripheral wall
portion 532 opposite to the first peripheral wall portion 531.
Therefore, the first peripheral wall portion 531 and the second
peripheral wall portion 532 adjoin both the soldering bottom
surface 51 and the top surface 52.
[0032] The soldering bottom surface 51 defines a first soldering
area 511 and a second soldering area 512. The first soldering area
511 adjoins the first peripheral wall portion 531 and the second
soldering area 512 adjoins the second peripheral wall portion 532.
The first soldering area 511 and the second soldering area 512 are
symmetrical. A first cutout 54 is defined between the first
peripheral wall portion 531 and the first soldering area 511 of the
bottom soldering surface 51 and a second cutout 55 is defined
between the first peripheral wall portion 531 and the first
soldering area 511 of the bottom soldering surface 51. The first
cutout 54 is symmetrical to the second cutout 55. Moreover, the
first cutout 54 can be defined between the first soldering area 511
of the bottom soldering surface 21 and the top surface 52, and the
second cutout 55 can be defined between the second soldering area
512 of the bottom soldering surface 51 and the top surface 52.
Preferably, the first cutout 54 should extend in a direction
perpendicular to the first soldering area 511, and the second
cutout 55 should extend in a direction perpendicular to the second
soldering area 512. Cross-section shape of the first cutout 54 and
the second cutout 55 taken normal to the bottom soldering surface
51 can be selected from the group consisting of arc-shaped,
U-shaped, V-shaped, and broken-lines-shaped. In the embodiment,
cross-section shape of the first cutout 54 taken normal to the
bottom soldering surface 51 is arc-shaped and cross-section shape
of the second cutout 55 taken normal to the bottom soldering
surface 51 is also arc-shaped. Additionally, a first soldering pad
513 and a second soldering pad 514 can be attached on the first
soldering area 511 and the second soldering area 512 respectively,
thereby facilitating soldering of the surface mounted electronic
component 50.
[0033] While certain embodiments have been described and
exemplified above, various other embodiments will be apparent to
those skilled in the art from the foregoing disclosure. The present
invention is not limited to the particular embodiments described
and exemplified but is capable of considerable variation and
modification without departure from the scope of the appended
claims.
* * * * *