U.S. patent application number 09/756007 was filed with the patent office on 2002-07-11 for flexible lead surface-mount semiconductor package.
Invention is credited to Wu, Jiahn-Chang.
Application Number | 20020089064 09/756007 |
Document ID | / |
Family ID | 25041626 |
Filed Date | 2002-07-11 |
United States Patent
Application |
20020089064 |
Kind Code |
A1 |
Wu, Jiahn-Chang |
July 11, 2002 |
Flexible lead surface-mount semiconductor package
Abstract
A diode chip is mounted on two bottom metal leads of a
surface-mount package through two flexible links. The links are
zigzag cantilevers attached to the metallic plates. The cantilevers
serve as springs to support the device and to cushion any
temperature stress or bending stress so as not to damage the
connection between the device and the metallic leads.
Inventors: |
Wu, Jiahn-Chang; (Hsinchu,
TW) |
Correspondence
Address: |
H.C. LIN
8 Schindler Court
Silver Spring
MD
20903
US
|
Family ID: |
25041626 |
Appl. No.: |
09/756007 |
Filed: |
January 8, 2001 |
Current U.S.
Class: |
257/773 ;
257/E23.044; 257/E23.045; 257/E23.047 |
Current CPC
Class: |
H01L 23/49551 20130101;
H01L 2224/48247 20130101; H01L 2224/48091 20130101; Y02P 70/613
20151101; H01L 2224/05599 20130101; H01L 2224/45099 20130101; H01L
23/49562 20130101; H01L 2924/12041 20130101; H01L 2924/12042
20130101; H01L 2924/00014 20130101; H01L 24/48 20130101; H01L
23/49544 20130101; H05K 3/3426 20130101; Y02P 70/50 20151101; H01L
2924/01046 20130101; H01L 2224/854 20130101; H01L 33/62 20130101;
H01L 2924/181 20130101; H01L 2224/48091 20130101; H01L 2924/00014
20130101; H01L 2924/12042 20130101; H01L 2924/00 20130101; H01L
2224/05599 20130101; H01L 2924/00014 20130101; H01L 2224/854
20130101; H01L 2924/00014 20130101; H01L 2924/00014 20130101; H01L
2224/45015 20130101; H01L 2924/207 20130101; H01L 2924/00014
20130101; H01L 2224/45099 20130101; H01L 2924/181 20130101; H01L
2924/00012 20130101 |
Class at
Publication: |
257/773 |
International
Class: |
H01L 023/48 |
Claims
1. A surface mount semiconductor device package, comprising; a
semiconductor device; and at least two metallic plates on which
said semiconductor device is mounted, said metallic plates having
bottom contacts for surface mounting to a motherboard and zigzag
cantilevers for making connections to said semiconductor
device.
2. A surface mount semiconductor device package as described in
claim 1, wherein said semiconductor device is a diode.
3. A surface mount semiconductor device package as described in
claim 2, wherein said zigzag cantilevers are horizontal.
4. A surface mount semiconductor device package as described in
claim 3, wherein said zigzag cantilevers are of inverted-U
shape.
5. A surface mount semiconductor device package as described in
claim 3, wherein said zigzag cantilevers are of inverted-V
shape.
6. A surface mount semiconductor device package as described in
claim 2, wherein said zigzag cantilevers are vertical.
7. A surface mount semiconductor device package as described in
claim 1, further comprising a glue to seal said semiconductor
device.
8. A surface mount semiconductor device package as described in
claim 2, wherein said diode has two bottom electrodes.
9. A surface mount semiconductor device as described in claim 2,
wherein said diode has a top electrode and a bottom electrode.
10. A surface mount semiconductor device as described in claim 9,
wherein said bottom electrode rests on the first plate of said
metallic plates and said top electrode is wire-bonded to the second
plate of said metallic plates.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to semiconductor device package,
particularly to surface mount optoelectric diode package, such as
that for a light emitting diode (LED), a laser diode (LD), a photo
diode (PD), etc. The invention is also applicable to a light sensor
diode, such as a image sensor. The invention may also be applicable
to packages for other non-optoelectric semiconductor devices.
[0003] 2. Brief Description of the Related Art
[0004] FIG. 1 shows a prior art optoelectric diode package. A
semiconductor chip 10 is mounted on two metallic plates 11, 12
serving as extension leads for a surface-mount diode package. The
chip 10 is sealed in glue 13 for protection. FIG.2 shows the side
view of the package. The outer portions of the metallic plates 11
and 12 are not covered with glue 13. The bottoms of the exposed
portions L, R are contact surfaces for surface mounting to a
motherboard. When the temperature changes, the motherboard may
bend, causing the device chip 10 to break away from the metallic
plates 11, 12. Then, the diode cannot function.
[0005] Another occasion for the device chip 10 to break away the
metallic plates 11,12 occurs when the diode package is mounted on a
curvilinear motherboard such as a display panel. The curving of the
surface can also cause bending stress on the device to damage the
device. An example of such a situation occurs when a decorative
light emitting ribbon is mounted at the corner of an automobile
body.
[0006] Still another occasion occurs for the keys of a computer key
board. Sometimes, the keys are lit with a light emitting diodes for
easy recognition in the dark. Due to constant pounding the keys,
the light emitting devices may dislodge from the leads.
SUMMARY OF THE INVENTION
[0007] An object of the present invention is to prevent an
optoelectric device from breaking away from the leads of a surface
mount package due to temperature stress. Another object of this
invention is to prevent a semiconductor device from breaking away
from the leads of surfacemount package due to bending stress.
[0008] These objects are achieved by mounting a semiconductor chip
to its bottom metal leads for surface mounting through two flexible
links. The links are zigzag cantilevers attached to the metallic
plates. The cantilevers serve as springs to support the device and
to cushion any temperature stress or bending stress so as not to
damage the connection between the device and the metallic
leads.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0009] FIG. 1 shows the top view of a prior art package for surface
mounting a diode chip to a motherboard.
[0010] FIG. 2 shows the side view of FIG. 1.
[0011] FIG. 3 shows the top view of diode package with two
horizontal zigzag cantilevers based on the present invention.
[0012] Fig. 4 shows the side view of Fig. 3.
[0013] FIG. 5 shows the top view of a second embodiment of the
package with two inverted V-shaped horizontal cantilevers.
[0014] FIG. 6 shows the side view of FIG. 5.
[0015] FIG. 7 shows the top view of a third embodiment of a package
with two vertical cantilevers.
[0016] FIG. 8 shows the side view of FIG. 7.
[0017] FIG. 9 shows the top view of a fourth embodiment of a
package with two horizontal zigzag cantilevers for packaging a
diode with a top electrode and a bottom electrode.
[0018] FIG. 10 shows the side view of FIG. 9.
DETAILED DESCRIPTION OF THE INVENTION
[0019] FIG. 3 shows the top view of the first embodiment of diode
package based on the present invention. A diode chip 20 is mounted
on two metallic plates 21, 22. The metallic plates 21 and 22 have a
rectangular cut 25 in the middle portion to form two horizontal
zigzag cantilevers. The cantilevers serve as springs. When the
package is subject to temperature variations, the spring action of
the zigzag cantilevers can cushion the expansion and contraction
stress. The chip 20 is sealed in glue 23 up to a portion of the
zigzag cantilevers as shown in side view FIG. 4. The bottoms of the
unsealed portions L1 and R1 of the metallic plates 21, 22 serve as
contacts for surface mounting the package to a motherboard.
[0020] FIG. 5 shows the top view of a second embodiment of this
invention. The diode chip 20 is mounted on two metallic plates 31,
32 as in FIG. 3. However the cut 35 in the metallic plates 31, 32
is of inverted V-shape (instead of being rectangular) to form the
zigzag cantilevers. Otherwise the function of zigzag cantilevers
are the same as in FIG. 3. The chip 20 is sealed in glue 23 up to a
portion of the zigzag cantilevers. FIG. 6 shows the side view of
FIG. 5, corresponding to FIG. 4. The bottoms of the unsealed
portions L2 and R2 of the metallic plates 31, 32 serve as contacts
for surface mounting the package to a motherboard.
[0021] FIG. 7 shows the top view of a third embodiment of the
present invention. The diode chip 20 is mounted on two metallic
plates 41, 42. The metallic plates are bent to form two two
vertical zigzag cantilevers 45. As in FIG. 3 and FIG. 5, the zigzag
cantilevers serve as springs to cushion the stress due to
temperature variations and bending. FIG. 8 shows the side view of
FIG. 7. The chip 20 is sealed in glue 23 up to a portion of the
zigzag cantilevers. The bottoms of the unsealed portions L3 and R3
of the metallic plates 41, 42 serve as contacts for surface
mounting the package to a motherboard.
[0022] FIG. 9 shows the top view of a fourth embodiment of the
present invention. The diode chip 50 has a top electrode and a
bottom electrode, unlike the chip 20 in previous embodiments with
two bottom electrodes. The diode chip 50 is mounted on a metallic
plate 52. The top electrode of diode chip 50 is wire-bonded by wire
56 to the second metallic plate 51, as shown in side view FIG. 10.
As in previous first and second embodiments, metallic plates 51 and
52 have cuts 55 to form horizontal zigzag cantilevers. The zigzag
cantilevers serve as springs to cushion the stress due to
temperature variations and bending. The chip 50 is sealed in glue
23 up to a portion a portion of the zigzag cantilevers. The bottoms
of the unsealed portions L4 and R4 of the metallic plates 51 and 52
respectively serve as contacts for surface mounting the package the
package to a motherboard.
[0023] While the preferred embodiments of the invention have been
described, it will be apparent to those skilled in the art that
various modifications may be made in the embodiments without
departing from the spirit of the present invention. Such
modifications are all within the scope of this invention.
* * * * *