Heat dissipation module

A high watt number heat dissipation module having externally exposed fins is disclosed. The high heat produced by semiconductor operation is dissipated employing the present module, and the packaging rubber body is prevented from overflow. The present module is mounted above the semiconductor wafer and the interior of the heat dissipation plate absorbs the high heat from the wafer, and heat energy is dissipated by means of the fins at the top portion of the heat dissipation plate. A plurality layers of skirts are provided at the surrounding of the heat dissipation plate and the number of layers o the skirts is dependent on the watt number of the wafer.

BACKGROUND OF THE INVENTION
 (a) Field of the Invention
 The present invention relates to a heat dissipation module, and in
 particular, to a heat dissipation module having externally exposed fins.
 (b) Description of the Prior Art
 Plastic Ball Grid Array (PBGA) is a packaging technique for integrated
 circuits and is employed in mass production manufacturing process. First,
 the wafer (5a) is milled, cut and adhered onto substrate 2a, after a
 lining process, the aluminum pad of the wafer 5a is connected to the
 welding line connection leg on the substrate. A gold line 6a is used for
 communication. The printed circuit board of the substrate 2a is connected
 to a tin ball connection leg at one side of the substrate 2a. Next, a
 synthetic resin rubber body 7a is used for packaging to protect the wafer
 5a and the gold line 6a. A welding ball 4a containing zinc, lead alloy is
 implanted onto the tin ball connection leg. Finally, cut off the remaining
 portion of the substrate 2a. A Plastic Ball Grid Array product is finally
 obtained. This Plastic Ball Grid Array product is welded to a main
 computer board 3a to complete the connection of the electronic parts to
 the main computer board.
 In application, the wafer on the substrate produces extreme heat during
 operation. Thus, a heat dissipation plate having high heat conduction and
 electrical conduction property is introduced at the top of the wafer of
 the Plastic Ball Grid Array and connecting the connection leg of the heat
 dissipation plate, and the ground connection of the PLASTIC BALL GRID
 ARRAY substrate. Thus, the interior of the heat dissipation plate is used
 to absorb heat source of the wafer and to dissipate heat energy via the
 surface of the heat dissipation plate.
 In view of the conventional heat dissipation plate being a simple cap-like
 structure (referring to FIG. 1), a fairly thick layer of synthetic resin
 rubber body (two times the thickness of a wafer) is mounted in between the
 heat dissipation plate and the wafer, the heat energy produced by the
 wafer can reach the heat dissipation plate by the conduction of the
 synthetic resin rubber body so as to dissipate heat. However, the
 synthetic resin rubber body is not a good conductor of heat and the heat
 from the wafer has to pass through the thick synthetic rubber body in
 order to attain the heat dissipation plate for heat dissipation. Thus, the
 heat dissipation efficiency is limited.
 Thus, the Plastic Ball Grid Array product obtained by this method needs
 appropriate heat dissipation blades to adhere to the conventional heat
 dissipation plate so as to dissipate heat. However, to implement this
 method, the conventional heat dissipation plate is adhered with a dual
 layer rubber. Generally the heat transfer coefficient of the dual layer
 rubber is not high, and thus, the entire heat dissipation effect is
 reduced, and it does not improve heat dissipation. After some period of
 application, the rubber body is hardened and cracked as a result of heat,
 and the externally mounted blades will be dislocated.
 SUMMARY OF THE PRESENT INVENTION
 It is therefore an object of this invention to provide a heat dissipation
 module having externally exposed fins, wherein a high performance
 conductive connecting rubber body directly absorbs heat produced from the
 surface of the wafer and dissipating the heat via the fins on the heat
 dissipation plate so as to increase heat dissipation effectiveness.
 Yet another object of this invention to provide a heat dissipation module
 having externally exposed fins, wherein a plurality of protruded layers at
 the external of the heat dissipation plate are used to improve heat
 dissipation effectiveness, and to provides positioning engagement and to
 prevent the overflow of the synthetic resin rubber body.
 Yet another object of the invention to provide a heat dissipation module
 having externally exposed fins, wherein the fin extended upward from the
 top section of the heat dissipation plate is used to increase the amount
 of the dissipated heat.

DETAILED DESCRIPTION OF THE PRESENT INVENTION
 The present invention relates to an engagement type, externally exposed fin
 heat dissipation module (as shown in FIG. 2), comprising a heat
 dissipation plate having a top section having a plurality of fins 12, and
 surrounded by a plurality layers of protruded skirts 11.
 In the process of manufacturing, the heat dissipation plate 1 of the
 present invention is provided directly above the wafer 5 and an elastic
 heat conduction adhesive rubber body 8 is connected to the top surface of
 the wafer 5 and the bottom surface of the interior of the heat dissipation
 plate 1. After that, a layer of synthetic resin rubber body 7 is provided
 to the interior and the exterior of the heat dissipation plate 1, and the
 boundary of the height of the rubber body 7 is at the highest level of the
 skirt 11. A protruded body lateral edge 110 of the skirt 11 leans against
 a rubber injection device to avoid the overflow of the synthetic resin
 rubber body 7. The synthetic resin rubber body 7 is provided to the
 internally covered area of the heat dissipation plate and distributed
 within the internally covered area of the heat dissipation plate 1 and the
 internally covered wafer 5, and the rest of the space of the elastic heat
 conduction adhesive rubber body 8.
 In accordance with the present invention, the heat energy produced by the
 wafer 5 is directly in contact with the heat conductive adhesive rubber
 body 8 which directly absorbs the heat that enters the dissipation plate
 1. The fins 12 at the top of the heat dissipation plate 1 are used to
 extend the heat dissipation area so as to dissipate heat. Also, the
 plurality layers of skirt 11 at the surrounding of the heat dissipation
 plate 1 are also helpful in dissipation of heat energy.
 The number of layers of the skirts is varied in accordance with the covered
 wafer watt number. For each layer of increment, the function of
 substantial heat dissipation area is increased. Thus it is easier to
 increase the number of layers to suit high watt number heat dissipation
 wafer, and the top portion of the skirt 11 is also functioned as a
 boundary to prevent overflow of synthetic resin rubber body 7. The notch
 of the skirts 11 is a mechanism providing the engagement of synthetic
 resin rubber body 7, and to enhance positioning of the module and to
 improve its reliability.
 While the invention has been described by way of example, it is to be
 understood that the invention is not limited to the disclosed embodiment.
 In the contrary, it is intended to cover various modifications to improve
 heat dissipation effect of PGBA. Therefore, the scope of the appended
 claims should be accorded broadest interpretation as to encompass all such
 modifications.