Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package – Insulating material
Reexamination Certificate
2003-06-25
2004-10-12
Ngô, Ngân V. (Department: 2814)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
Insulating material
C257S675000, C257S706000, C257S719000
Reexamination Certificate
active
06803654
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a heat-radiating structure of chip, which applies to flip chip package structures to have better heat-radiating paths. Moreover, the stability of the heat-radiating structure can be enhanced, and local concentration of stress and damage caused by aging and fatigue can be reduced.
BACKGROUND OF THE INVENTION
As shown in
FIGS. 1 and 2
, a conventional heat-radiating structure of chip comprises a circuit substrate
1
a
. A chip
2
a
of flip chip structure is connected on the circuit substrate
1
a
. An array of several solder balls
21
a
are disposed at the bottom face of the chip
2
a
to form a contact face. Ball sockets
11
a
are correspondingly disposed at the top face of the circuit substrate
1
a
so that part of each solder ball
21
a
can be connected at a corresponding ball socket
11
a
. A structure for electronic signal transmission with other circuit boards is disposed at the bottom face of the circuit substrate
1
a
. This structure is a ball grid array
3
a
in
FIG. 1
, and can also be a pin grid array. In addition to electronic signal transmission, the ball grid array
3
a
can also provide a heat-spreading path for the working chip
2
a.
However, along with increase of the operating power of the chip
2
a
, more heat is generated per unit time so that simply the heat-spreading path of the ball grid array
3
a
is not sufficient. Therefore, the temperature of the chip
2
a
itself becomes higher and higher, hence affecting the working performance of the chip or even damaging the chip.
Accordingly, a heat-radiating component
4
a
is further disposed on the chip
2
a
. The heat-radiating component
4
a
comprises a high frame
5
a
and a heat-radiating plate
6
a
. The high frame
5
a
provides support to the heat-radiating plate
6
a
on the circuit substrate
1
a
. The heat-radiating plate
6
a
adheres to the high frame
5
a
and the surface of the chip
2
a
through an adhesive
7
a
(as shown in FIG.
2
). The high frame
5
a
also adheres to the circuit substrate
1
a
through the adhesive
7
a.
Although the conventional heat-radiating component, provides a good heat-spreading area and a certain degree of protection for the chip, it is of a two-piece design so that more cost is required in assembly steps and time and the use quantity of adhesive.
Besides, due to temperature rise when the chip operates and temperature drop when the chip stops operating, local concentration of stress and aging and fatigue at the adhesive regions will occur because of thermal cycle loading and difference between thermal expansion coefficients of different materials, hence causing local damage to result in falling off of the heat-radiating component from the chip.
Accordingly, the above heat-radiating structures of chip have inconvenience and drawbacks in practical use. The present invention aims to resolve the problems in the prior art.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a heat-radiating structure of chip having an integrally formed heat-radiating component. The heat-radiating structure of chip can provide a good structural rigidity and stability, decrease thermal stress damage caused by thermal deformation, and reduce local concentration of stress and damage caused by aging and fatigue.
Another object of the present invention is to provide a heat-radiating structure of chip having a separately disposed bearing rack. The bearing rack forms an intermittent structure to avoid positions with a too large local thermal stress. Moreover, the use quantity of adhesive can be reduced, and the requirement in adhesion strength can be lowered. Moreover, gaps of the bearing rack provide flow passages for hot air in the heat-radiating component.
To achieve the above objects, the present invention provides a heat-radiating structure of chip disposed around a flip chip type chip on a circuit substrate. The heat-radiating structure of chip comprises a heat-radiating sheet for conducting out beat of the chip and a bearing rack extended from the heat-radiating sheet. The bearing rack is disposed near sides of the heat-radiating sheet facing the surface of the chip. Moreover, an adhesive is connected between the top face of the chip and the surface of the heat-radiating sheet.
The present invention also provides another heat-radiating structure of chip disposed around a flip chip type chip on a circuit substrate. The heat-radiating structure of chip comprises a heat-radiating sheet for conducting out heat of the chip and a bearing rack extended from the heat-radiating sheet. The bearing rack is disposed near sides of the heat-radiating sheet facing the surface of the chip. The bearing rack is divided into at least two parts. Moreover, an adhesive is connected between the top face of the chip and the surface of the heat-radiating sheet.
The present invention also provides another heat-radiating structure of chip disposed around a flip chip type chip on a circuit substrate. The heat-radiating structure of chip comprises a heat-radiating sheet for conducting out heat of the chip and a bearing rack extended from the heat-radiating sheet. The bearing rack is disposed near sides of the heat-radiating sheet facing the surface of the chip. Each side of the bearing rack is divided into at least two parts, and each side of the bearing rack is not connected to one another. Moreover, an adhesive is connected between the top face of the chip and the surface of the heat-radiating sheet.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing, in which:
REFERENCES:
patent: 6400014 (2002-06-01), Huang et al.
patent: 2003/0067070 (2003-04-01), Kwon et al.
Lee Tzung-Lung
Lin Ming-Chen
Advanced Thermal Technologies
Browdy and Neimark , P.L.L.C.
Ngo Ngan V.
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