U.S. patent application number 09/461022 was filed with the patent office on 2001-12-13 for structure for mounting radiating plate.
Invention is credited to EGAWA, SATOSHI.
Application Number | 20010050844 09/461022 |
Document ID | / |
Family ID | 18461807 |
Filed Date | 2001-12-13 |
United States Patent
Application |
20010050844 |
Kind Code |
A1 |
EGAWA, SATOSHI |
December 13, 2001 |
STRUCTURE FOR MOUNTING RADIATING PLATE
Abstract
A radiating-plate mounting structure for mounting a radiating
plate on a semiconductor integrated circuit installed on a printed
circuit board is arranged to have a pin disposed on the printed
circuit: board in the neighborhood of the semiconductor integrated
circuit and to fix the radiating plate to the semiconductor
integrated circuit by pressing the radiating plate with a spring
member using a lock part of the pin as a fulcrum. At this time, the
middle part of the radiating plate can be reliably fixed to the
semiconductor integrated circuit by a hole provided in the spring
member for allowing a fin part of the radiating plate to escape
through the hole. The structural arrangement effectively eliminates
the possibility of having the radiating plate caused to peel off by
some impact inflicted thereon.
Inventors: |
EGAWA, SATOSHI;
(KAWASAKI-SHI, JP) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Family ID: |
18461807 |
Appl. No.: |
09/461022 |
Filed: |
December 15, 1999 |
Current U.S.
Class: |
361/720 ;
257/E23.086 |
Current CPC
Class: |
H01L 2924/0002 20130101;
H01L 2924/0002 20130101; H01L 23/4093 20130101; H01L 2924/00
20130101 |
Class at
Publication: |
361/720 |
International
Class: |
H05K 007/20 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 17, 1998 |
JP |
HEI 10-358921 |
Claims
1. A radiating-plate mounting structure, comprising: a printed
circuit board; a semiconductor integrated circuit installed on said
printed circuit board; a radiating plate provided on said
semiconductor integrated circuit; and spring urging means for
pressing and fixing said radiating plate onto said semiconductor
integrated circuit.
2. A radiating-plate mounting structure according to claim 1,
wherein said spring urging means includes pins provided on said
printed circuit board at positions on two sides of said
semiconductor integrated circuit, and a spring spanned and bridged
across said semiconductor integrated circuit between said pins to
press and fix said radiating plate onto said semiconductor
integrated circuit.
3. A radiating-plate mounting structure according to claim 2,
wherein said pins are made of a metal material and fixed to said
printed circuit board by soldering, and said spring urging means
are spanned and bridged between said metal pins with said metal
pins used as fulcra.
4. A radiating-plate mounting structure according to claim 3,
wherein each of said metal pins is arranged to have a predetermined
distance of clearance between said printed circuit board and a part
thereof serving as said fulcrum when said metal pins are fixed by
soldering to said printed circuit board.
5. A radiating-plate mounting structure according to claim 3,
wherein said metal pins are connected to a signal ground of said
printed circuit board when said metal pins are fixed by soldering
to said printed circuit board.
6. A radiating-plate mounting structure according to claim 3,
wherein said metal pins are approximately in an U shape.
7. A radiating-plate mounting structure according to claim 3,
wherein said metal pins are approximately in an E shape.
8. A radiating-plate mounting structure according to claim 2,
wherein said radiating plate has a plurality of fins, and said
spring urging means is provided with a hole for allowing at least
one of the plurality of fins of said radiating plate to escape
through said hole.
9. A radiating-plate mounting structure, comprising: a printed
circuit board; a semiconductor integrated circuit installed on said
printed circuit board, said semiconductor integrated circuit being
of a flat package type, a radiating plate provided on said
semiconductor integrated circuit, said radiating plate having a
plurality of fins; a first pin provided on said printed circuit
board at a position on one side of said semiconductor integrated
circuit, said first pin having a lock part; a second pin provided
on said printed circuit board at a position on the other side of
said semiconductor integrated circuit, said second pin having a
lock part; and a spring member having one end thereof locked to the
lock part of said first pin and the other end thereof locked to the
lock part of said second pin, said spring member being arranged to
press and fix, with a middle part thereof, said radiating plate to
said semiconductor integrated circuit.
10. A radiating-plate mounting structure according to claim 9,
wherein said spring member is provided with a hole for allowing at
least one of the plurality of fins of said radiating plate to
escape through said hole.
11. A radiating-plate mounting structure, comprising: a printed
circuit board; a semiconductor integrated circuit installed on said
printed circuit board, said semiconductor integrated circuit being
of a flat package type; a radiating plate provided on said
semiconductor integrated circuit, said radiating plate having a
plurality of fins; a pin provided on said printed circuit board
adjacent to said semiconductor integrated circuit, said pin having
a lock part; and a spring member arranged to press and fix said
radiating plate onto said semiconductor integrated circuit with the
lock part of said pin used as a fulcrum, said spring member being
provided with a hole for allowing at least one of the plurality of
fins of said radiating plate to escape through said hole.
12. A radiating-plate mounting structure according to claim 11,
wherein said spring member has a pressing part arranged
approximately at a central part thereof to press and fix said
radiating plate onto said semiconductor integrated circuit.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a structure for mounting a
radiating plate which is provided on a semiconductor integrated
circuit to be installed in a printed circuit board.
[0003] 2. Description of Related Art
[0004] Semiconductor integrated circuits have recently come to be
prepared to have a high degree of density. As a result, the heat
build-up amount of flat-package-type semiconductor integrated
circuits is trending upward. It has become difficult to
sufficiently lower the temperature of these semiconductor
integrated circuits by natural cooling. The semiconductor
integrated circuits, however, must be cooled, because exposing them
to high temperature tends to cause them to malfunction.
[0005] Known methods for cooling the flat-package-type
semiconductor integrated circuits include air cooling by mounting a
radiating plate (a heat sink), forcible cooling with a cooling fan,
and cooling by Peltier effect attained with a Peltier element.
[0006] The methods of using a cooling fan or a Peltier element give
an excellent cooling effect. However, these methods have
necessitated securing a power source for operating the cooling fan
or the Peltier element and also have incurred an inevitable
increase in cost due to the addition of the cooling fan or the
Peltier element.
[0007] The method of mounting a radiating plate permits cooling the
semiconductor integrated circuit at a lower cost than the methods
of using a cooling fan or a Peltier element. For mounting the
radiating plate on the flat-package-type semiconductor integrated
circuit, it has been practiced to secure the radiating plate to the
semiconductor integrated circuit by bonding with an adhesive, a
double-sided adhesive tape or the like.
[0008] However, in cases where a shake or a downfall happens to
inflict an impact on the radiating plate which is bonded with an
adhesive, the bonded part of radiating plate tends to peel off. In
such a case, the radiating plate would part from the semiconductor
integrated circuit, becoming incapable of fulfilling its cooling
function.
BRIEF SUMMARY OF THE INVENTION
[0009] The present invention is directed to the solution of the
above-stated problem of the prior art. An object of the invention
is, therefore, to provide a structure for mounting a radiating
plate on a semiconductor integrated circuit in such a way as to
ensure that the radiating plate is never caused to peel off by any
impact inflicted thereon.
[0010] To attain the above object, in accordance with an aspect of
the invention, there is provided a radiating-plate mounting
structure, comprising, a printed circuit board, a semiconductor
integrated circuit installed on the printed circuit board, a
radiating plate provided on the semiconductor integrated circuit,
and spring urging means for pressing and fixing the radiating plate
onto the semiconductor integrated circuit.
[0011] The above and other objects and features of the invention
will become apparent from the following detailed description of
preferred embodiments taken in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEW OF THE DRAWING
[0012] FIG. 1 is a perspective view showing a printed circuit board
on which a semiconductor integrated circuit to which a radiating
plate is fixed is mounted, according to a first embodiment of the
invention.
[0013] FIG. 2 is a sectional view showing a radiatingplate mounting
part shown in FIG. 1.
[0014] FIGS. 3(a), 3(b) and 3(c) are diagrams for explaining
procedures for mounting pins, a QFPIC (flat-package-type
semiconductor integrated circuit), a radiating plate and a spring
member shown in FIG. 1.
[0015] FIG. 4 is a plan view showing the pin shown in FIG. 2.
[0016] FIGS. 5(a) and 5(b) are a plan view and a front view,
respectively, showing the spring member shown in FIG. 2.
[0017] FIGS. 6(a) and 6(b) are a side view and a front view,
respectively, showing the radiating plate shown in FIG. 2.
[0018] FIG. 7 is a plan view showing a pin whose shape is different
from that of the pin shown in FIG. 4, according to a second
embodiment of the invention.
[0019] FIGS. 8(a) and 8(b) are a plan view and a front view,
respectively, showing a spring member arranged in combination with
the pin shown in FIG. 7.
DETAILED DESCRIPTION OF THE INVENTION
[0020] Hereinafter, preferred embodiments of the invention will be
described in detail with reference to the drawings.
[0021] First, a first embodiment of the invention is described with
reference to FIG. 1 to FIGS. 6(a) and 6(b). FIG. 1 shows a printed
circuit board on which a semiconductor integrated circuit to which
a radiating plate is fixed is mounted. In FIG. 1, there are
illustrated a pin 101 which is formed approximately in a U shape, a
spring member 102, a radiating plate 103 (or a heat sink), a
flat-package-type semiconductor integrated circuit 104 (hereinafter
referred to as QFPIC), and a printed circuit board 105.
[0022] FIG. 2 is a sectional view taken along a line AA in FIG. 1
to show a mount part where the radiating plate 103 is mounted.
Referring to FIG. 2, metal pins 101a and 101b each of which is
formed approximately in a U shape are soldered to the printed
circuit board 105. The radiating plate 103 is fixed to the QFPIC
104 in a state of being pushed to the QFPIC 104 by the urging force
of the spring member 102 with the upper sides of the metal pins
101a and 101b used as fulcra.
[0023] FIGS. 3(a), 3(b) and 3(c) are diagrams for explaining
procedures for mounting the approximately-U-shaped pins 101, the
QFPIC 104, the radiating plate 103 and the spring member 102.
[0024] Referring to FIG. 3(a), the approximately-Ushaped metal pins
101a and 101b are fixed by soldering to the printed circuit board
105 at through-hole parts 302a and 302b thereof. The QFPIC 104 has
its lead wire parts soldered to the printed circuit board 105 at
its parts 301a and 301b. The soldering is performed by the same
process by which other parts are fixed by soldering to the printed
circuit board 105. With the printed circuit board 105 designed to
have the through-hole parts 302a and 302b connected at this time to
the signal ground of the printed circuit board 105, the soldered
approximately-U-shaped pins 101a and 101b are connected to the
signal ground of the printed circuit board 105.
[0025] Referring to FIG. 3(b), next, the radiating plate 103 is
temporarily fixed to the QFPIC 104 with an adhesive, a double-sided
adhesive tape or the like. The adhesive or the double-sided
adhesive tape to be used at that time, of course, must have a good
thermal conductivity.
[0026] Referring to FIG. 3(c), next, the spring member 102 is
mounted in such a way as to push the radiating plate 103 against
the QFPIC 104 with the approximately-U-shaped pins 101a and 101b
used as fulcra. The radiating-plate mounting steps are as follows.
The spring member 102 is first set in an approximately vertical
posture to have its one end 303 in touch with the
approximately-U-shaped pin 101a. Then, the spring member 102 is
swung in this state in the direction of an arrow 350. At this time,
a fin 601 which is formed at the center of the radiating plate 103
as shown in FIG. 6(a) comes into a hole 50 provided in the center
part of the spring member 102 as shown in FIG. 5(a), so that the
spring member 102 is prevented from colliding with the radiating
plate 103. With the swinging motion of the spring member 102 made
further, when the spring member 102 comes to be approximately in
parallel to the printed circuit board 105, the tip 306 of a
V-shaped part 305 provided in the center part of the spring member
102 comes to abut on the radiating plate 103. Then, the spring
member 102 is further swung in a pushing manner until the other end
304 thereof comes to touch the approximately-U-shaped pin 101b.
After that, the spring member 102 is slid in the direction of an
arrow 351 (to the right as viewed in FIG. 3(c)). In this state, a
pushing force is exerted on the radiating plate 103 at the tip 306
of the V-shaped part 305 of the spring member 102.
[0027] FIG. 4 is a plan view showing each of the
approximately-U-shaped pins 101 (101a and 10b) used in the first
embodiment. Referring to FIG. 4, the pin 101 is soldered to the
printed circuit board 105 by inserting parts 401 of the pin 101
into through holes of the printed circuit board 105. Parts 402 of
the pin 101 serve to keep a predetermined distance of clearance
between the printed circuit board 105 and the upper side of the pin
101 which acts as a fulcrum. The approximately-U-shaped pin 101 is
formed with a hard metal.
[0028] FIG. 5(a) is a plan view of the spring member 102 used in
the first embodiment. FIG. 5(b) is a front view of the spring
member 102. The spring member 102 is made of an elastic metal and
is provided with a hole 501 in its middle part for allowing a fin
part of the radiating plate 103 to escape therethrough.
[0029] FIG. 6(a) is a side view of the radiating plate 103 used in
the first embodiment. FIG. 6(b) is a front view of the radiating
plate 103. The radiating plate (heat sink) 103 excels in thermal
conductivity and is made of a light metal such as aluminum or the
like. To enhance its efficiency of cooling, the radiating plate 103
is provided with a plurality of fins 601.
[0030] In the arrangement described above, the
approximately-U-shaped pins 101a and 101b are soldered to the QFPIC
104 at positions on both sides thereof. With the
approximately-U-shaped pins 101a and 101b used as fulcra, the
radiating plate 103 is fixed to the QFPIC 104 in a state of being
pressed against the QFPIC 104 by the spring member 102.
[0031] Further, the spring member 102 can be readily dismounted and
removed according to procedures which are reverse to the mounting
procedures described above. Therefore, the QFPIC 104 which is
soldered can be easily replaced.
[0032] According to the invention, each metal pin which is soldered
to the printed circuit board 105 does not have to be in the
approximate U shape. The metal pin may be arranged in any other
suitable shape as long as the pin is provided with some lock part.
FIG. 7 shows in a plan view an E-shaped pin 701 which is employed
in a second embodiment of the invention. Referring to FIG. 7, the
E-shaped pin 701 has a leg part 702 at which the pin 701 is
soldered to the printed circuit board 105 with the leg part 702
inserted into a through hole formed in the printed circuit board
105. Parts 703 of the pin 701 are arranged to maintain a
predetermined distance of clearance between the printed circuit
board 105 and the upper side of the pin 701 which is used as a
fulcrum after the pin 701 is soldered to the printed circuit board
105.
[0033] FIG. 8(a) is a plan view of a spring member 801 which is
arranged according to the shape of the E-shaped pin 701. FIG. 8(b)
is a front view of the spring member 801. Since the pin 701 has the
leg part 702 formed at the center thereof, a cut-in part 803 is
provided in each end of the spring member 801 for preventing the
spring member 801 from touching the center leg part 702 of the pin
701. Further, as in the first embodiment, the spring member 801 has
a hole 802 formed in its middle part for allowing the fin of the
radiating plate 103 to escape therethrough.
[0034] The procedures for mounting the parts of the second
embodiment described above are identical with the mounting
procedures of the first embodiment and are, therefore, omitted from
the description. Although the second embodiment has the E-shaped
pin 701 and the spring member 801 arranged as described above, the
E-shaped pin 701 is soldered to a position on each of two sides of
the QFPIC 104 and the spring member 801 is mounted thereon. With
the spring member 801 thus mounted, the radiating plate 103 can be
fixed in position in a state of being pushed against the QFPIC 104
as in the case of the first embodiment.
[0035] According to the invention, as described in the foregoing,
the radiating plate, i.e., a heat sink, which is mounted on the
semiconductor integrated circuit is fixed in position with a spring
member. Therefore, the radiating plate, i.e., the heat sink, is
never caused to peel off the semiconductor integrated circuit by
vibrations or shakes nor by a downfall impact inflicted
thereon.
[0036] In replacing the semiconductor integrated circuit on which
the radiating plate is mounted, the replacing work can be easily
carried out as the spring member and the radiating plate are
removable without difficulty.
[0037] Further, since the heat sink can be connected to the signal
ground through the metal pin and the spring member, radiant noises
of the semiconductor integrated circuit can be adequately
suppressed.
* * * * *