Circuit board and preparation method thereof

Abstract

The invention discloses a circuit board and a preparation method thereof. The preparation method comprises the steps that a circuit substrate is provided, the circuit substrate comprises a first surface and a second surface which are opposite in the first direction, a through groove is formed in the circuit substrate, and a first opening and a second opening are formed in the first surface and the second surface through the through groove respectively; a first heat dissipation block and a second heat dissipation block are provided, the first heat dissipation block comprises a first extension part and a first body part, the second heat dissipation block comprises a second extension part and a second body part, in the second direction, the width of the first extension part is larger than that of the first body part, and the width of the second extension part is larger than that of the second body part; respectively covering the first surface and the second surface with a first adhesive layer and a second adhesive layer; a first heat dissipation block is inserted into the through groove from the first opening, a second heat dissipation block is inserted into the through groove from the second opening, and then pressing is carried out. The first heat dissipation block and the second heat dissipation block can be prevented from being separated from the side wall of the through groove.

Description

Technical Field

[0001] The present application relates to the field of circuit boards, and in particular to a circuit board and a method for preparing the same. Background Art

[0002] With the increasing demand for electronic products such as computers, consumer electronics, and communications, and the diversification of electronic products’ functions, the electronic components in electronic products are becoming more and more centralized. As the support and carrier for the electrical connection of electronic components, heat dissipation has become a huge problem facing the circuit board industry.

[0003] Therefore, it is usually necessary to arrange copper blocks in the circuit board as heat sinks. However, when subjected to external forces (such as during subsequent processing or transportation of the circuit board), the copper blocks are easily separated from the side walls of the slot, thereby causing the circuit board to fail. Summary of the invention

[0004] In view of this, it is necessary to provide a circuit board with heat dissipation function.

[0005] In addition, the present application also provides a method for preparing the above-mentioned circuit board.

[0006] The first aspect of the present application provides a method for preparing a circuit board, comprising: providing a circuit substrate, the circuit substrate comprising a first surface and a second surface arranged opposite to each other in a first direction, a through groove being provided in the circuit substrate, the through groove forming a first opening and a second opening on the first surface and the second surface respectively; providing a first heat dissipation block and a second heat dissipation block, the first heat dissipation block comprising a first extension portion and a first main body portion connected to each other, the second heat dissipation block comprising a second extension portion and a second main body portion connected to each other, in a second direction perpendicular to the first direction, the width of the first extension portion is greater than the width of the first main body portion, and the width of the second extension portion is greater than the width of the second main body portion; on the first surface and the second surface The first surface is covered with a first adhesive layer and a second adhesive layer, respectively, and the first adhesive layer and the second adhesive layer are provided with a first window and a second window, respectively. When observed from the first direction, the first window overlaps with the first opening, and the second window overlaps with the second opening; the first heat dissipation block is inserted into the through groove from the overlap between the first window and the first opening, and the second heat dissipation block is inserted into the through groove from the overlap between the second window and the second opening to obtain an intermediate; the intermediate is pressed together so that the first extension portion is combined with the first surface through the first adhesive layer, and the second extension portion is combined with the second surface through the second adhesive layer, thereby obtaining the circuit board.

[0007] In some possible implementations, when forming the through slot, the through slot includes a main slot body and at least one positioning slot body recessed in the side wall of the main slot body. When providing the first heat sink block and the second heat sink block, the first heat sink block also includes at least one first positioning protrusion protruding from the side wall of the first body portion, and the second heat sink block also includes at least one second positioning protrusion protruding from the side wall of the second body portion. When inserting the first heat sink block and the second heat sink block, the first positioning protrusion and the second positioning protrusion are respectively inserted into the positioning slot body from both sides.

[0008] In some possible implementations, the number of the positioning grooves is two, and they are respectively recessed on two adjacent side walls of the main groove. The number of the first positioning protrusions is two, and they are respectively protruded on two adjacent side walls of the first body. The number of the second positioning protrusions is two, and they are respectively protruded on two adjacent side walls of the second body.

[0009] In some possible implementations, in a cross section perpendicular to the first direction, the two positioning grooves are semicircular and have different radii.

[0010] In some possible implementations, after the pressing, in the first direction, the sum of the thickness of the first body portion and the thickness of the second body portion is equal to the depth of the through groove.

[0011] The second aspect of the present application provides a circuit board, comprising a circuit substrate, a first adhesive layer, a second adhesive layer and a heat sink. The circuit substrate comprises a first surface and a second surface arranged opposite to each other in a first direction, a through slot is provided in the circuit substrate, and the through slot forms a first opening and a second opening on the first surface and the second surface respectively. The first adhesive layer is provided on the first surface, and the first adhesive layer is provided with a first window, and when viewed from the first direction, the first window and the first opening overlap. The second adhesive layer is provided on the second surface, and the second adhesive layer is provided with a second window, and when viewed from the first direction, the second window and the second opening overlap. The heat sink comprises a first heat sink block and a second heat sink block. The first heat sink block comprises a first extension portion and a first main body portion connected to each other, and in a second direction perpendicular to the first direction, the width of the first extension portion is greater than the width of the first main body portion, the first main body portion passes through the first window and the first opening and is provided in part of the through slot, and the first extension portion is combined with the first surface through the first adhesive layer. The second heat dissipation block includes a second extension portion and a second main body portion connected to each other. In the second direction, the width of the second extension portion is greater than the width of the second main body portion. The second main body portion passes through the second window and the second opening and is arranged in another part of the through groove. The second extension portion is combined with the second surface through the second adhesive layer.

[0012] In some possible implementations, the through slot includes a main slot body and at least one positioning slot body recessed in the side wall of the main slot body. The first heat sink block also includes at least one first positioning protrusion protruding from the side wall of the first body portion, and the second heat sink block also includes at least one second positioning protrusion protruding from the side wall of the second body portion. The first positioning protrusion and the second positioning protrusion are disposed in the positioning slot body and are in contact with each other.

[0013] In some possible implementations, the number of the positioning grooves is two, and they are respectively recessed on two adjacent side walls of the main groove. The number of the first positioning protrusions is two, and they are respectively protruded on two adjacent side walls of the first body. The number of the second positioning protrusions is two, and they are respectively protruded on two adjacent side walls of the second body.

[0014] In some possible implementations, in a cross section perpendicular to the first direction, the two positioning grooves are semicircular and have different radii.

[0015] In some possible implementations, in the first direction, the sum of the thickness of the first body portion and the thickness of the second body portion is equal to the depth of the through groove.

[0016] In the present application, since the first extension portion and the second extension portion are respectively combined with the circuit substrate through the first adhesive layer and the second adhesive layer, and the first extension portion and the second extension portion are larger in size in the second direction, thereby increasing the bonding area, when the circuit board is subjected to external force, the provision of the first extension portion and the second extension portion is beneficial to reducing the risk of separation between the heat sink and the circuit substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic structural diagram of a circuit substrate provided in one embodiment of the present application.

[0018] Figure 2 For Figure 1 The schematic diagram of the structure after a through groove is opened in the circuit substrate is shown.

[0019] Figure 3 For Figure 2 A top view of the circuit substrate is shown.

[0020] Figure 4 For Figure 2 The schematic diagram of the structure is shown after both sides of the circuit substrate are covered with insulating layers and heat sinks.

[0021] Figure 5 For pressing Figure 4 The schematic diagram of the structure of the circuit board obtained after the structure shown.

[0022] Figure 6 for Figure 5 The circuit board shown is a cross-sectional view along VI-VI.

[0023] Main component symbols

[0024] Circuit board 1

[0025] Circuit board 10

[0026] Circuit layer 11

[0027] Insulation layer 12

[0028] Through slot 13

[0029] Heat sink 20

[0030] The first heat sink 21

[0031] The second heat sink 22

[0032] The first adhesive layer 30

[0033] First window 31

[0034] Second adhesive layer 40

[0035] Second window 41

[0036] First surface 101

[0037] First opening 101a

[0038] Second surface 102

[0039] The second opening 102a

[0040] Main tank 131

[0041] Positioning slot 132

[0042] The first extension portion 211

[0043] First body part 212

[0044] First positioning protrusion 213

[0045] The second extension portion 221

[0046] Second body portion 222

[0047] The second positioning protrusion 223

[0048] First direction X

[0049] Second direction Y

[0050] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0051] In order to more clearly understand the above-mentioned objects, features and advantages of the present application, the present application is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. In the following description, many specific details are set forth in order to fully understand the present application, and the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes all and any combination of one or more related listed items.

[0053] In the embodiments of the present application, for the convenience of description and not to limit the present application, the term "connection" used in the patent application specification and claims of the present application is not limited to physical or mechanical connection, whether direct or indirect. "Up", "down", "above", "below", "left", "right", etc. are only used to indicate relative position relationship. When the absolute position of the described object changes, the relative position relationship also changes accordingly.

[0054] An embodiment of the present application provides a method for preparing a circuit board 1, comprising the following steps:

[0055] Step S1: Please refer to Figure 1 , a circuit substrate 10 is provided, which includes a first surface 101 and a second surface 102 arranged opposite to each other in a first direction X.

[0056] In some embodiments, the circuit substrate 10 includes a plurality of circuit layers 11 stacked along a first direction X and an insulating layer 12 disposed between two adjacent circuit layers 11 . The outermost circuit layer 11 forms a first surface 101 , and the outermost circuit layer 11 forms a second surface 102 .

[0057] In one embodiment, the material of the insulating layer 12 is an insulating resin. For example, the material of the insulating layer 12 can be selected from one of epoxy resin, prepreg (PP), BT resin, polyphenylene oxide (PPO), polyimide (PI), polyethylene terephthalate (PET) and polyethylene naphthalate (PEN).

[0058] In some embodiments, the circuit substrate 10 may be a high density interconnect board or a flexible circuit board. The circuit layer 11 of the circuit substrate 10 may be made of copper.

[0059] Step S2: Please refer to Figure 2 and Figure 3 A through groove 13 is formed in the circuit substrate 10, and the through groove 13 penetrates the entire circuit substrate 10 along the first direction X. That is, the through groove 13 penetrates the first surface 101 and the second surface 102, thereby forming a first opening 101a and a second opening 102a on the first surface 101 and the second surface 102, respectively.

[0060] In some embodiments, the through slot 13 includes a main slot body 131 and at least one positioning slot body 132 recessed in a side wall of the main slot body 131 . Figure 2 and Figure 3, it is shown in some embodiments that the number of the positioning grooves 132 can be two, which are respectively recessed on two adjacent side walls of the main groove 131. Each of the main groove 131 and the positioning groove 132 penetrates the first surface 101 and the second surface 102 along the first direction X. In some specific embodiments, in a cross section perpendicular to the first direction X, the main groove 131 is square, and each positioning groove 132 is semicircular with different radii, for example, the radius of one positioning groove 132 is approximately 1 mm, and the radius of the other positioning groove 132 is approximately 2 mm.

[0061] In some embodiments, the through slot 13 may be formed by mechanical drilling. The position of the through slot 13 may avoid the position of the conductive circuit in the circuit layer 11 .

[0062] Step S3, see Figure 4 , providing a first heat dissipation block 21 and a second heat dissipation block 22.

[0063] The first heat sink 21 and the second heat sink 22 are both T-shaped structures. The first heat sink 21 includes a first extension portion 211 and a first main body portion 212 connected to each other. The first main body portion 212 can be formed by protruding outward from the center of the first extension portion 211. In the second direction Y perpendicular to the first direction X, the width of the first extension portion 211 is greater than the width of the first main body portion 212.

[0064] The second heat dissipation block 22 may have a similar structure to the first heat dissipation block 21. The second heat dissipation block 22 includes a second extension portion 221 and a second body portion 222 connected to each other. The second body portion 222 may be formed by protruding outward from the center of the second extension portion 221. In the second direction Y, the width of the second extension portion 221 is greater than the width of the second body portion 222.

[0065] Further, when the through slot 13 is designed to include a main slot body 131 and a positioning slot body 132, the first heat sink 21 also includes at least one first positioning protrusion 213 protruding from the side wall of the first body portion 212. Similarly, the first heat sink 21 also includes at least one second positioning protrusion 223 protruding from the side wall of the second body portion 222. In a cross section perpendicular to the first direction X, the size of the first positioning protrusion 213 matches the size of the positioning slot body 132, and the size of the second positioning protrusion 223 also matches the size of the positioning slot body 132. In some specific embodiments, the number of the first positioning protrusion 213 can be two, which are respectively protruding from two adjacent side walls of the first body portion 212; the number of the second positioning protrusion 223 can be two, which are respectively protruding from two adjacent side walls of the second body portion 222.

[0066] In some embodiments, the first heat sink 21 and the second heat sink 22 can be made of metal or alloy with a large thermal conductivity. The materials of the first heat sink 21 and the second heat sink 22 can be the same or different. In some specific embodiments, the materials of the first heat sink 21 and the second heat sink 22 can both be copper, silver, aluminum or steel.

[0067] Step S4, see Figure 4 The first surface 101 and the second surface 102 are covered with a first adhesive layer 30 and a second adhesive layer 40 respectively.

[0068] The first adhesive layer 30 and the second adhesive layer 40 are respectively provided with a first window 31 and a second window 41. When viewed from the first direction X, the first window 31 of the first adhesive layer 30 overlaps with the first opening 101a, and the second window 41 of the second adhesive layer 40 overlaps with the second opening 102a.

[0069] In some embodiments, when viewed from the first direction X, the first window 31 of the first adhesive layer 30 completely overlaps with the first opening 101 a , and the second window 41 of the second adhesive layer 40 completely overlaps with the second opening 102 a .

[0070] In one embodiment, the material of the first adhesive layer 30 and the second adhesive layer 40 is an insulating resin, for example, the material of each of the first adhesive layer 30 and the second adhesive layer 40 can be selected from one of epoxy resin, prepreg (PP), BT resin, polyphenylene oxide (PPO), polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), etc. The materials of the first adhesive layer 30 and the second adhesive layer 40 can be the same or different.

[0071] Step S5, see Figure 4 and Figure 5 , insert the first heat sink 21 into the through groove 13 from the overlapping portion between the first window 31 and the first opening 101a, and insert the second heat sink 22 into the through groove 13 from the overlapping portion between the second window 41 and the second opening 102a, to obtain an intermediate body (not shown).

[0072] It can be understood that when the through slot 13 includes the main slot body 131 and the positioning slot body 132, and the first heat sink 21 and the second heat sink 22 respectively include the first positioning protrusion 213 and the second positioning protrusion 223, during the insertion of the first heat sink 21, the first positioning protrusion 213 is inserted into the positioning slot body 132 from one side, and during the insertion of the second heat sink 22, the second positioning protrusion 223 is inserted into the positioning slot body 132 from the other side. The mutual cooperation between the positioning protrusion and the positioning slot body can play a role in directional positioning and guiding during the insertion of the heat sink.

[0073] Step S6, see Figure 5 and Figure 6 , the intermediate body is pressed together so that the first heat sink 21 and the second heat sink 22 are in contact in the through groove 13. At the same time, the first extension 211 of the first heat sink 21 is combined with the first surface 101 through the first adhesive layer 30, and the second extension 221 of the second heat sink 22 is combined with the second surface 102 through the second adhesive layer 40. At this time, the circuit board 1 is obtained.

[0074] The first body portion 212 of the first heat sink 21 is disposed in a portion of the through slot 13, and the first extension portion 211 of the first heat sink 21 protrudes from the first surface 101. The second body portion 222 of the second heat sink 22 is disposed in another portion of the through slot 13, and the second extension portion 221 of the second heat sink 22 protrudes from the second surface 102. The first body portion 212 and the second body portion 222 are in contact in the through slot 13 to form a heat conduction channel (combined with reference to Figure 4 When the first positioning protrusion 213 and the second positioning protrusion 223 are provided, the first positioning protrusion 213 and the second positioning protrusion 223 also contact each other in the through groove 13 after being pressed together. In the first direction X, the sum of the thickness of the first body portion 212 and the thickness of the second body portion 222 may be substantially equal to the depth of the through groove 13. The first heat sink 21 and the second heat sink 22 together form the heat sink 20.

[0075] During operation, the heat generated in the circuit layer 11 can be firstly conducted to the first main body 212 of the first heat dissipation block 21 and the second main body 222 of the second heat dissipation block 22, and then to the first extension part 211 and the second extension part 221, and then to the outside through the first extension part 211 and the second extension part 221, so as to achieve heat dissipation. Since the first extension part 211 and the second extension part 221 have larger dimensions in the second direction Y, the arrangement of the first extension part 211 and the second extension part 221 is conducive to increasing the heat dissipation area of ​​the heat dissipation body 20, thereby improving the heat dissipation efficiency. Among them, if the temperature of the part of the circuit substrate 10 near the first surface 101 is higher, the heat can be dissipated through the first main body 212, the second main body 222 and the second extension part 221 in sequence; on the contrary, if the temperature of the part of the circuit substrate 10 near the second surface 102 is higher, the heat can be dissipated through the second main body 222, the first main body 212 and the first extension part 211 in sequence. Thus, the heat dissipation effect on both sides can be balanced, thereby improving the overall heat dissipation capacity of the circuit board 1.

[0076] Furthermore, in the present application, since the first extension portion 211 and the second extension portion 221 are respectively combined with the circuit substrate 10 through the first adhesive layer 30 and the second adhesive layer 40, and the first extension portion 211 and the second extension portion 221 have larger dimensions in the second direction Y, thus increasing the combined area, when the circuit board 1 is subjected to external force, the provision of the first extension portion 211 and the second extension portion 221 is conducive to reducing the risk of separation between the heat sink 20 and the circuit substrate 10. In addition, the provision of the first positioning protrusion 213 and the second positioning protrusion 223, which are respectively matched with the positioning groove body 132 of the through groove 13, is also conducive to increasing the contact area between the heat sink 20 and the side wall of the through groove 13, thereby further reducing the risk of separation between the heat sink 20 and the circuit substrate 10 under the action of external force.

[0077] See also Figure 5 and Figure 6 In one embodiment of the present application, a circuit board 1 prepared by the above preparation method is provided, comprising a circuit substrate 10, a first adhesive layer 30, a second adhesive layer 40 and a heat sink 20. The circuit substrate 10 comprises a first surface 101 and a second surface 102 arranged opposite to each other in a first direction X. A through groove 13 is provided in the circuit substrate 10, and the through groove 13 runs through the entire circuit substrate 10 along the first direction X, thereby forming a first opening 101a and a second opening 102a on the first surface 101 and the second surface 102, respectively.

[0078] The first adhesive layer 30 and the second adhesive layer 40 are respectively disposed on the first surface 101 and the second surface 102. When viewed from the first direction X, the first window 31 of the first adhesive layer 30 overlaps with the first opening 101a, and the second window 41 of the second adhesive layer 40 overlaps with the second opening 102a.

[0079] The heat sink 20 includes a first heat sink 21 and a second heat sink 22. The first heat sink 21 includes a first extension portion 211 and a first main body portion 212 connected to each other. In a second direction Y perpendicular to the first direction X, the width of the first extension portion 211 is greater than the width of the first main body portion 212. The second heat sink 22 includes a second extension portion 221 and a second main body portion 222 connected to each other. In the second direction Y, the width of the second extension portion 221 is greater than the width of the second main body portion 222. The first main body portion 212 of the first heat sink 21 passes through the first window 31 and the first opening 101a and is disposed in a portion of the through groove 13. The first extension portion 211 of the first heat sink 21 is combined with the first surface 101 through the first adhesive layer 30. The second main body portion 222 of the second heat sink 22 passes through the second window 41 and the second opening 102a and is disposed in another portion of the through groove 13. The second extension portion 221 of the second heat sink 22 is combined with the second surface 102 through the second adhesive layer 40. The first body portion 212 and the second body portion 222 are in contact with each other in the through groove 13 to form a heat conduction channel.

[0080] Combined with reference Figure 4 In some embodiments, the through slot 13 includes a main slot body 131 and at least one positioning slot body 132 recessed in the side wall of the main slot body 131. Each of the main slot body 131 and the positioning slot body 132 penetrates the first surface 101 and the second surface 102 along the first direction X. The first heat sink 21 also includes at least one first positioning protrusion 213 protruding from the side wall of the first body portion 212, and the first heat sink 21 also includes at least one second positioning protrusion 223 protruding from the side wall of the second body portion 222. The first positioning protrusion 213 and the second positioning protrusion 223 are in contact in the through slot 13, and the contacting first positioning protrusion 213 and second positioning protrusion 223 are located in the positioning slot body 132.

[0081] The above implementation modes are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the above preferred implementation modes, a person skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for preparing a circuit board, characterized in that: include: Providing a circuit substrate, the circuit substrate comprising a first surface and a second surface arranged opposite to each other in a first direction, a through groove being provided in the circuit substrate, the through groove forming a first opening and a second opening on the first surface and the second surface respectively; A first heat sink and a second heat sink are provided, wherein the first heat sink comprises a first extension portion and a first main body portion connected to each other, and the second heat sink comprises a second extension portion and a second main body portion connected to each other, wherein in a second direction perpendicular to the first direction, a width of the first extension portion is greater than a width of the first main body portion, and a width of the second extension portion is greater than a width of the second main body portion; The first surface and the second surface are covered with a first adhesive layer and a second adhesive layer, respectively, the first adhesive layer and the second adhesive layer are provided with a first window and a second window, respectively, and when viewed from the first direction, the first window overlaps with the first opening, and the second window overlaps with the second opening; Insert the first heat dissipation block into the through groove from the overlap between the first window and the first opening, and insert the second heat dissipation block into the through groove from the overlap between the second window and the second opening to obtain an intermediate body; as well as The intermediate body is pressed together so that the first extension part is combined with the first surface through the first adhesive layer, and the second extension part is combined with the second surface through the second adhesive layer, thereby obtaining the circuit board.

2. The method for preparing a circuit board according to claim 1, characterized in that: When forming the through groove, the through groove comprises a main groove body and at least one positioning groove body recessed in the side wall of the main groove body; When providing the first heat dissipation block and the second heat dissipation block, the first heat dissipation block further includes at least one first positioning protrusion protruding from the side wall of the first body portion, and the second heat dissipation block further includes at least one second positioning protrusion protruding from the side wall of the second body portion; When the first heat dissipation block and the second heat dissipation block are inserted, the first positioning protrusion and the second positioning protrusion are respectively inserted into the positioning slot from both sides.

3. The method for preparing a circuit board according to claim 2, characterized in that: There are two positioning grooves, which are respectively recessed on two adjacent side walls of the main groove; there are two first positioning protrusions, which are respectively protruded on two adjacent side walls of the first main body; there are two second positioning protrusions, which are respectively protruded on two adjacent side walls of the second main body.

4. The method for preparing a circuit board according to claim 3, characterized in that: In a cross section perpendicular to the first direction, the two positioning slots are semicircular and have different radii.

5. The method for preparing a circuit board according to claim 1, characterized in that: After the pressing, in the first direction, the sum of the thickness of the first body portion and the thickness of the second body portion is equal to the depth of the through groove.

6. A circuit board, characterized in that: include: A circuit substrate, comprising a first surface and a second surface arranged opposite to each other in a first direction, wherein a through groove is provided in the circuit substrate, and the through groove forms a first opening and a second opening on the first surface and the second surface respectively; A first adhesive layer is disposed on the first surface, the first adhesive layer is provided with a first window, and when viewed from the first direction, the first window overlaps with the first opening; A second adhesive layer is disposed on the second surface, the second adhesive layer is provided with a second window, and when viewed from the first direction, the second window overlaps with the second opening; as well as A heat sink comprises a first heat sink and a second heat sink, wherein the first heat sink comprises a first extension portion and a first main body portion connected to each other, wherein in a second direction perpendicular to the first direction, the width of the first extension portion is greater than the width of the first main body portion, the first main body portion passes through the first window and the first opening and is disposed in a portion of the through groove, and the first extension portion is combined with the first surface through the first adhesive layer; and the second heat sink comprises a second extension portion and a second main body portion connected to each other, wherein in the second direction, the width of the second extension portion is greater than the width of the second main body portion, the second main body portion passes through the second window and the second opening and is disposed in another portion of the through groove, and the second extension portion is combined with the second surface through the second adhesive layer.

7. The circuit board according to claim 6, characterized in that: The through groove includes a main groove body and at least one positioning groove body recessed in the side wall of the main groove body; the first heat dissipation block also includes at least one first positioning protrusion protruding from the side wall of the first main body part, and the second heat dissipation block also includes at least one second positioning protrusion protruding from the side wall of the second main body part; the first positioning protrusion and the second positioning protrusion are arranged in the positioning groove body and contact each other.

8. The circuit board according to claim 7, characterized in that: There are two positioning grooves, which are respectively recessed on two adjacent side walls of the main groove; there are two first positioning protrusions, which are respectively protruded on two adjacent side walls of the first main body; there are two second positioning protrusions, which are respectively protruded on two adjacent side walls of the second main body.

9. The circuit board according to claim 8, characterized in that: In a cross section perpendicular to the first direction, the two positioning slots are semicircular and have different radii.

10. The circuit board according to claim 6, characterized in that: In the first direction, the sum of the thickness of the first body portion and the thickness of the second body portion is equal to the depth of the through groove.

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