CN110459512A - Heat dissipation mainboard and optical module - Google Patents

Abstract

The application relates to the technical field of optical communication, in particular to a heat dissipation main board and an optical module. A heat dissipation mainboard is used for packaging a chip and comprises a circuit board and a heat dissipation piece, wherein the heat dissipation piece is located on one side of the circuit board, and the chip is arranged on the other side of the circuit board. The circuit board is provided with a heat dissipation through hole corresponding to the chip, and the heat dissipation through hole penetrates through two sides of the circuit board. At least part of the heat dissipation piece extends into the heat dissipation through hole and can be in contact with the chip, so that heat generated during the working of the chip can be transferred out, heat transfer resistance is reduced, effective heat dissipation is achieved for the chip, and the problem of difficulty in heat dissipation of a COB bare chip is solved. The utility model provides an optical module, includes heat dissipation mainboard and chip and casing, heat dissipation mainboard and chip are located the casing, and the heat dissipation piece of heat dissipation mainboard contacts with chip and casing respectively to the heat that produces the chip transmits to the casing fast, thereby reaches high-efficient radiating effect.

Description

Cooling motherboard and optical module

technical field

The invention relates to the technical field of optical communication, in particular to a heat dissipation main board and an optical module.

Background technique

In the field of optical communication, it is often necessary to use the COB (chip on board) process to package chips with specific functions on the PCB (printed circuit board), and the current mainstream method is to paste the chip on a specific chip on the PCB. area. However, after the chip is attached to the PCB, the heat cannot be directly transferred to the corresponding metal shell by using a thermal interface material or a metal heat dissipation block, which makes this process have a large heat dissipation disadvantage.

In response to the above problems, the current conventional practice is to drill through holes in the COB area of the PCB and use overheating holes for heat dissipation. However, due to the limited content of the thermally conductive material at the overheating hole, the heat transfer effect is poor, which may easily cause heat concentration and increase the chip temperature.

Contents of the invention

The purpose of the present application is to provide a heat dissipation motherboard and an optical module to solve the technical problem in the prior art that the heat dissipation effect of the chip is poor when the chip is packaged on the PCB using the COB process.

The application provides a heat dissipation motherboard, which is used for packaging chips, including a circuit board and heat dissipation parts;

A heat dissipation through hole is opened on the circuit board corresponding to the packaging position of the chip; the heat dissipation element is located on one side of the circuit board, and at least part of the heat dissipation element extends into the heat dissipation through hole and can contact with the chip on the other side of the circuit board.

In the above technical solution, preferably, a raised portion is formed on the heat sink, and the raised portion protrudes into the heat dissipation through hole and can be in contact with the chip;

The end surface of the heat sink on the side facing the circuit board is attached to the circuit board.

In any of the above technical solutions, preferably, the heat dissipation motherboard further includes a first thermally conductive adhesive layer, and the first thermally conductive adhesive layer is disposed between the raised portion of the heat sink and the chip.

In any of the above technical solutions, preferably, the heat dissipation motherboard further includes a metal layer, the metal layer is located between the heat dissipation element and the circuit board, or the metal layer is located on the protrusion of the heat dissipation element section and the chip.

In any of the above technical solutions, preferably, the heat dissipation motherboard further includes a second thermally conductive adhesive layer, and the second thermally conductive adhesive layer is located between the metal layer and the raised portion of the heat sink.

In any of the above technical solutions, preferably, a vent hole is formed on the heat sink, and the vent hole communicates with the second thermally conductive adhesive layer and/or the first thermally conductive adhesive layer.

In any of the above technical solutions, preferably, a thermal interface material layer is provided on the side of the heat sink away from the circuit board.

In any of the above technical solutions, preferably, the thermal conductivity of the heat sink and the thermal conductivity of the metal layer are both greater than 15W/(m·K).

The present application also provides an optical module, including the heat dissipation motherboard described in any of the above technical solutions and the chip, the chip is located on one side of the circuit board and is in contact with the heat dissipation element.

In the above technical solution, preferably, the optical module further includes a casing, and an accommodating space is formed in the casing, the chip and the heat dissipation motherboard are both located in the accommodating space, and the heat dissipation member and the The shells are in contact.

Compared with prior art, the beneficial effect of the present invention is:

The present application provides a heat dissipation motherboard for packaging chips, including a circuit board and a heat sink; wherein, the heat sink is located on one side of the circuit board, and the chip is arranged on the other side of the circuit board. A cooling through hole is opened on the position corresponding to the chip on the circuit board, and the cooling through hole runs through both sides of the circuit board. At least part of the heat sink extends into the heat dissipation through hole and can be in contact with the chip, so that the heat generated by the chip can be transferred out with maximum efficiency, reducing the heat transfer thermal resistance, and effectively cooling the chip , which solves the problem of difficult heat dissipation of the COB bare chip. In addition, the heat dissipation parts of the heat dissipation main board of the present application are easy to assemble, and the heat dissipation parts can be bonded after the circuit board is processed.

The present application also provides an optical module, including the heat dissipation main board, a chip and a housing, the heat dissipation main board and the chip are located in the housing, and the heat dissipation parts of the heat dissipation main board are respectively in contact with the chip and the housing to dissipate the heat produced by the chip. The heat is quickly transferred to the shell, so as to achieve the effect of efficient heat dissipation.

Description of drawings

In order to more clearly illustrate the specific implementation of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the specific implementation or description of the prior art. Obviously, the accompanying drawings in the following description The drawings show some implementations of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative work.

FIG. 1 is a schematic diagram of an exploded structure of a first optical module provided by an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional structural diagram of the first optical module provided by an embodiment of the present invention;

Fig. 3 is the enlarged view of place A in Fig. 2;

FIG. 4 is a schematic diagram of an exploded structure of a second optical module provided by an embodiment of the present invention;

FIG. 5 is a schematic cross-sectional structural diagram of a second optical module provided by an embodiment of the present invention;

FIG. 6 is an enlarged view of B in FIG. 5 .

Reference signs:

1-circuit board, 101-heat dissipation through hole, 2-radiation piece, 201-raised part, 202-air vent, 3-chip, 4-metal layer, 5-thermal interface material layer, 6-top cover, 7- lower lid.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Apparently, the described embodiments are some of the embodiments of the present invention, but not all of them.

The components of the embodiments of the invention generally described and shown in the figures herein may be arranged and designed in a variety of different configurations. Accordingly, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention.

Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, or in a specific orientation. construction and operation, therefore, should not be construed as limiting the invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

The following describes a heat dissipation motherboard and an optical module including the heat dissipation motherboard according to some embodiments of the present invention with reference to FIGS. 1 to 6 .

Referring to Fig. 1 to Fig. 6, the present application provides a heat dissipation motherboard for packaging a chip 3, including a circuit board 1 and a heat sink 2; wherein, the heat sink 2 is located on one side of the circuit board 1, and the chip 3 is arranged on The other side of the board 1. The position corresponding to the chip 3 on the circuit board 1 is provided with a heat dissipation through hole 101 , and the heat dissipation through hole 101 runs through both sides of the circuit board 1 . At least part of the heat dissipation element 2 extends into the heat dissipation through hole 101 and is in contact with the chip 3, that is, the heat dissipation element 2 can be completely embedded in the heat dissipation through hole 101 in the shape of a block or a strip, and directly contacts the chip 3, or the heat dissipation element 2 A protruding part extending into the heat dissipating via hole 101 may be formed on the top, and the protruding part is in contact with the chip 3 and conducts heat.

Preferably, a protruding portion 201 is formed on the side of the heat sink 2 facing the circuit board 1, and the protruding portion 201 can pass through the heat dissipation through hole 101 and contact the chip 3, so as to maximize the efficiency of the heat generated by the chip 3 during operation. The transmission of the heat transfer reduces the heat transfer resistance, thereby effectively dissipating heat from the chip 3 and solving the problem of difficult heat dissipation of the COB bare chip. In addition, the heat sink 2 is easy to assemble, and the heat sink 2 can be bonded after the circuit board 1 is processed without affecting the sticking of the chip 3 .

In this embodiment, preferably, the protrusion 201 of the heat sink 2 is adapted to the shape of the heat dissipation through hole 101, and the end surface of the end of the heat sink 2 in contact with the chip 3 is a plane, so that the heat sink 2 can be in contact with the chip 3. The chip 3 is better bonded and contacted, and the heat dissipation efficiency of the heat sink 2 to the chip 3 is improved.

In this embodiment, preferably, as shown in FIG. 2, FIG. 3 and FIG. 5, FIG. The adhesive material is bonded to the circuit board 1 to realize a firm connection between the heat sink 2 and the circuit board 1, and it is not easy to loosen; and the side wall of the raised portion 201 can be attached to the inner wall of the heat dissipation through hole 101 to further Make the connection between the cooling element 2 and the circuit board 1 stable.

In the embodiment of the present application, the heat sink 2 can be made of pure copper, copper alloy, pure aluminum, aluminum alloy and other metal and non-metal materials with a thermal conductivity greater than 15W/(m·K) or aluminum nitride ceramics And other ceramic materials to ensure heat dissipation efficiency.

It should be noted that the number of heat dissipation vias 101 on the circuit board 1 is one or more, so as to correspond to packaging different numbers of chips 3 .

The heat dissipation motherboard of the embodiment of the present application further includes a metal layer 4 , which belongs to the ground layer and is disposed between the chip 3 and the heat sink 2 , or between the heat sink 2 and the circuit board 1 . Preferably, the metal layer 4 is disposed between the chip 3 and the raised portion 201 of the heat sink 2 , or between the end surface of the heat sink 2 facing the circuit board 1 and the circuit board 1 . Two preferred implementations of the heat dissipation motherboard of the present application will be described below with the two preferred arrangements of the metal layer 4 .

As shown in Figures 1 to 3, when the metal layer 4 is disposed between the chip 3 and the raised portion 201 of the heat sink 2, a first thermally conductive adhesive layer is provided on one side of the metal layer 4, and the metal layer 4 passes through the first The thermally conductive adhesive layer is bonded and fixed to the chip 3 ; a second thermally conductive adhesive layer is provided on the other side of the metal layer 4 , and the metal layer 4 is bonded and fixed to the raised portion 201 of the heat sink 2 through the second thermally conductive adhesive layer.

As shown in FIGS. 4 to 6 , when the metal layer 4 is located between the end face of the heat sink 2 facing the circuit board 1 and the circuit board 1 , the metal layer 4 is arranged in a ring shape, and the metal layer 4 surrounds the protrusion of the heat sink 2 . The starting part 201 is set. Under this structure, the metal layer 4 can also be bonded and fixed to the heat sink 2 and the circuit board 1 through a thermally conductive adhesive material. The chip 3 and the raised portion 201 of the heat sink 2 are directly bonded and fixed through the first heat-conducting adhesive layer.

It should be noted that, in order not to affect the heat dissipation effect, the thermal conductivity of the metal layer is greater than 15W/(m K); preferably, the material of the metal layer 4 is copper; the thermally conductive bonding material is a material with good thermal conductivity, Such as silver paste; in addition, thermally conductive adhesive materials can have conductive properties or electrical insulating properties.

In the embodiment of the present application, preferably, as shown in FIG. 2 and FIG. 3 , in order to avoid that when the metal layer 4 is bonded to the heat sink 2 and the chip 3, the bubbles generated on the bonding surface will cause the metal layer 4 to bulge and deform. In the embodiment of the present application, a vent hole 202 is provided on the heat sink 2 , and the vent hole 202 communicates with the second thermally conductive adhesive layer or the first thermally conductive adhesive layer. When the first thermally conductive adhesive layer and the second thermally conductive adhesive layer are disposed on both sides of the metal layer 4 respectively, the vent hole 202 can pass through the metal layer 4 and simultaneously communicate with the first thermally conductive adhesive layer and the second thermally conductive adhesive layer. By providing the vent holes 202 connected to the heat-conducting adhesive layer, the air in the adhesive layer can be exhausted to the vent holes 202 , so the metal layer 4 is not easily caused to bulge and deform.

It should be noted that, the first thermally conductive adhesive layer and the second thermally conductive adhesive layer are adhesive layers formed by thermally conductive adhesives or adhesive layers formed by solder.

In the embodiment of the present application, preferably, as shown in FIGS. The housings of the modules are in contact to transfer the heat absorbed by the heat sink 2 to the housing of the optical module. Since the housing of the optical module is generally made of metal, the heat can be dissipated quickly.

Preferably, the material of the thermal interface material layer 5 includes but not limited to thermal pad, thermal paste, graphene and the like.

In addition, it should be noted that when the thermal interface material layer 5 is provided between the heat sink 2 and the housing of the optical module, the stepped surface formed on the heat sink 2 can also play the role of limiting and supporting. 1 (it has been bonded into one body with the heat sink 2), it will be squeezed by the thermal interface material layer 5, and the squeeze force will act on the heat sink 2, but because the circuit board 1 will affect the step formed on the heat sink 2 The surface forms a limit, so the raised part 201 of the heat sink 2 will not produce relative displacement relative to the circuit board 1 and protrude from the side surface of the circuit board 1 facing the chip 3, so that the circuit board can be avoided due to the displacement of the heat sink 2. 1 or the gold wire of chip 3 is broken or deformed, and at the same time, it can effectively avoid the risk of chip 3 falling off caused by the protrusion of the bottom area of chip 3 .

The embodiment of the present application also provides an optical module, including the heat dissipation main board and the chip 3 and the housing of any of the above embodiments, the heat dissipation main board and the chip 3 are located in the housing, and the heat dissipation parts 2 of the heat dissipation main board are respectively connected to the chip 3 and the housing. The shells are in contact with each other, so as to quickly transfer the heat generated by the chip 3 to the shell, so as to achieve the purpose of efficient heat dissipation.

Preferably, for the convenience of assembly and disassembly, as shown in FIGS. 1 to 6 , the housing includes an upper cover 6 and a lower cover 7 , which can be fastened and connected to enclose an accommodation space. The heat sink 2 of the heat dissipation motherboard can be in contact with the lower cover 7 of the housing, so as to quickly transfer the heat generated by the chip 3 to the lower cover 7 .

Further preferably, the material of the lower cover 7 is metal, so that the lower cover 7 has better heat dissipation and strength.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (10)

1. a kind of heat dissipation mainboard, for encapsulating chip, which is characterized in that including circuit board and radiating piece；

It is corresponded on the circuit board and offers thermal vias at the package position of the chip；The radiating piece is located at the circuit The side of plate, and the radiating piece be extending at least partially into the thermal vias and can be with the institute of the circuit board other side Chip is stated to be in contact.

2. heat dissipation mainboard according to claim 1, which is characterized in that lug boss is formed on the radiating piece, it is described convex The portion of rising protrudes into the thermal vias and can be in contact with the chip；

The end face of the radiating piece towards the side of the circuit board fits with the circuit board.

3. heat dissipation mainboard according to claim 2, which is characterized in that further include the first conducting adhesive layer, described first leads Hot adhesion layer is set between the lug boss of the radiating piece and the chip.

4. heat dissipation mainboard according to claim 3, which is characterized in that further include metal layer, the metal layer is located at described Between radiating piece and the circuit board or the metal layer is located between the lug boss and the chip of the radiating piece.

5. heat dissipation mainboard according to claim 4, which is characterized in that further include the second conducting adhesive layer, described second leads Hot adhesion layer is between the metal layer and the lug boss of the radiating piece.

6. heat dissipation mainboard according to claim 5, which is characterized in that venthole is formed on the radiating piece, it is described logical Stomata is connected to the second conducting adhesive layer and/or the first conducting adhesive layer.

7. heat dissipation mainboard according to claim 1, which is characterized in that the radiating piece is set away from the side of the circuit board It is equipped with heat-conducting interface material layer.

8. heat dissipation mainboard according to claim 4, which is characterized in that the thermal coefficient of the radiating piece and the metal layer Thermal coefficient be all larger than 15W/ (mK).

9. a kind of optical module, which is characterized in that including heat dissipation mainboard described in any item of the claim 1 to 8 and the chip, The chip is located at the side of the circuit board, and is in contact with the radiating piece.

10. optical module according to claim 9, which is characterized in that further include shell, formed in the shell and accommodate sky Between, the chip and the heat dissipation mainboard are respectively positioned in the accommodation space, and the radiating piece is in contact with the shell.