Natural convection induction type heat sink and semiconductor package including the same

Abstract

The heat sink body has an area larger than or equal to that of the substrate, and includes a contact area formed at the center of the heat sink body that directly or indirectly contacts the silicon die formed on the substrate, a plurality of fixing portions formed on the outer periphery of the heat sink body that directly contact the substrate, and a plurality of openings formed between the fixing portions on the outer periphery of the heat sink body to form spaces of a certain height from the substrate.

Description

[Technical field]

[0001] The present invention relates to a natural convection induction type heat sink and a semiconductor package including the same. [Background technology]

[0002] Electronic packaging serves to physically, chemically, and mechanically protect the semiconductor chip from the external environment, and also to efficiently transfer external signals and power to the inside of the semiconductor chip to support the functionality of the semiconductor chip.

[0003] That is, electronic packaging performs functions such as distributing power or signals, dissipating heat, and protecting semiconductor chips from the outside world. Among these, the function of effectively dissipating heat from semiconductor chips is one of the most important functions of electronic packaging.

[0004] As the integration of elements in electronic components increases and they become lighter, thinner, and smaller, the heat generated by the elements increases, which can cause the reliability of semiconductor elements to decrease.In addition, the difference in thermal expansion coefficient between the semiconductor chip and the electronic packaging element can increase the thermal stress applied to the solder that connects the materials and the element, which can shorten the life of the electronic packaging element.

[0005] To solve this problem, it is possible to consider ways to improve heat dissipation, such as modifying the product design, adding a thermal path, or applying high-performance materials, etc. However, reflecting such considerations has the disadvantage of requiring changes to the product's exterior shape and design, changes to the appearance, and increased production costs. Summary of the Invention [Problem to be solved by the invention]

[0006] SUMMARY OF THE PRESENTLY PREFERRED EMBODIMENTS An object of the present invention is to provide a natural convection induction type heat sink that can easily dissipate heat generated from a silicon die by modifying the external shape of the heat sink, and a semiconductor package having the same. [Means for solving the problem]

[0007] The heat sink, which is one of the features of the present invention for achieving the technical object of the present invention, is The heat sink body includes a contact area formed at the center of the heat sink body and indirectly contacting a silicon die formed on the substrate, a plurality of fixing parts formed on an outer periphery of the heat sink body and in direct contact with the substrate, and a plurality of openings formed between the fixing parts on the outer periphery of the heat sink body to form a space of a certain height from the substrate.

[0008] The heat sink body may be embodied in a rectangular shape.

[0009] The plurality of fixing parts may be formed on four sides of an outer periphery of the heat sink body.

[0010] The plurality of openings may be formed at four vertices of an outer periphery of the heat sink body.

[0011] The plurality of fixing portions may be formed at four vertices of an outer periphery of the heat sink body, respectively.

[0012] The plurality of openings may be formed on four sides of an outer periphery of the heat sink body.

[0013] At least one of the plurality of openings may be an inlet through which air generated by a cooling fan flows in, and at least one of the plurality of openings may be an outlet through which the inlet air is discharged together with heat of the silicon die.

[0014] The outlet can release heat generated in the silicon die to the outside by natural convection due to a temperature difference between the silicon die and the periphery of the silicon die.

[0015] Another feature of the present invention for achieving the technical object of the present invention is a semiconductor package comprising: The heat sink includes a substrate having a circuit pattern and a rectangular plane, a silicon die formed on the substrate and electrically connected to the substrate, and a heat sink formed on the silicon die and dissipating heat generated in the silicon die to the outside, the heat sink including a plurality of fixing parts formed by directly contacting the substrate for a certain length based on four vertices of an outer periphery of the heat sink or a part of the length of each of the four sides, and a plurality of openings formed between the fixing parts and spaced a certain height from the substrate.

[0016] The cooling device may further include a cooling fan configured to blow air into any one of the plurality of openings.

[0017] The heat sink may release heat generated in the silicon die by natural convection through a contact area that directly or indirectly contacts the silicon die due to a temperature difference between the silicon die and the surrounding area of ​​the silicon die, and wind flowing into at least one of the plurality of openings may be discharged together with the heat of the silicon die through at least one of the plurality of openings. Effect of the Invention

[0018] According to the present invention, an open-type shape structure is applied without changing the material and size of the heat sink, and natural convection and forced convection by a cooling fan are simultaneously applied, thereby improving the heat dissipation effect of the semiconductor chip.

[0019] In addition, the improved heat dissipation prevents the package from overheating during operation, ensuring product reliability.

[0020] In addition, by maintaining a structure in which at least four points are fixed to the board, it is possible to prevent warping defects due to high temperatures, and when a heat sink is applied, it is possible to maintain a more stable heat sink balance by increasing the mounting area. [Brief description of the drawings]

[0021] [Figure 1] 1 is a diagram illustrating a semiconductor package to which a general sealed type heat sink is applied; [Diagram 2] 1 is a diagram illustrating a semiconductor package to which a general open-type heat sink is applied; [Diagram 3] 1 illustrates a semiconductor package according to an embodiment of the present invention. [Figure 4a] 1 is a diagram illustrating an open-type heat sink according to an embodiment of the present invention; [Figure 4b] 1 is a diagram illustrating an open-type heat sink according to an embodiment of the present invention; [Diagram 5] 4 is a diagram illustrating a heat flow in a heat sink according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily carry out the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. In the drawings, parts that are not necessary for the purpose of clearly explaining the present invention are omitted, and similar parts are designated by similar reference numerals throughout the specification.

[0023] Throughout the specification, when a part is said to "comprise" a certain element, this means that it can further include other elements, but not to the exclusion of other elements, unless specifically stated to the contrary.

[0024] Hereinafter, a natural convection induction type heat sink and a semiconductor package including the same according to an embodiment of the present invention will be described with reference to the drawings. Before describing the embodiment of the present invention, a general heat sink will be described with reference to Figs. 1 and 2.

[0025] FIG. 1 is a diagram illustrating a semiconductor package to which a typical sealed type heat sink is applied.

[0026] 1(a), a commonly used semiconductor package 10 has a silicon die 12, which is a semiconductor chip, attached to a substrate 11. A heat sink 13 is configured to be in direct or indirect contact with the silicon die 12 not only to protect the silicon die 12 from the outside but also to dissipate heat generated by the silicon die 12. Because the silicon die 12 and the heat sink 13 are in contact with each other, heat generated by the silicon die 12 can be transferred through the contact area and dissipated to the outside.

[0027] At this time, four surfaces of the heat sink 13 are in contact with the substrate 11. Therefore, conductive heat generated in the silicon die 12 can be transferred to the substrate 11 through the contact surfaces of the four surfaces in contact with the substrate 11 and dissipated to the outside.

[0028] However, since the heat sink 13 and the substrate 11 are attached in a sealed form on all four sides using a thermal interposer material (TIM), a natural heat flow, i.e., natural convection, occurs inside the semiconductor package 10 due to temperature differences at different positions inside the semiconductor package 10.

[0029] 1(b), a cooling fan 20 is implemented as an additional component for heat dissipation in combination with the semiconductor package 10. However, the forced convection of the cooling fan 20 restricts the heat dissipation within the semiconductor package 10.

[0030] In other words, natural heat flow from the high temperature area to the low temperature area should occur, and convection circulation should occur, but in a sealed structure, convection circulation is not possible, and heat transfer by natural convection is not possible, so the temperature inside the sealed structure reaches a thermal saturation state after a certain period of operation.

[0031] FIG. 2 is a diagram illustrating a semiconductor package to which a typical open-type heat sink is applied.

[0032] 2, the open-type heat sink 32 is embodied in such a form that two opposing surfaces are in close contact with the substrate 31 and the other two opposing surfaces are spaced apart from the substrate 31 to form an open area. The semiconductor package 30 to which the open-type heat sink 32 is applied can be expected to have more effective natural convection and forced convection by a cooling fan than the semiconductor package 10 having the sealed-type heat sink 13 of FIG. 1.

[0033] However, since only two surfaces of the heat sink 32 in the semiconductor package 30 are attached to the substrate 31, there is a mechanical vulnerability such as an increase in package warpage due to changes in reflow temperature during surface mounting technology (SMT). This may lead to electrical open or short defects between the semiconductor package 30 and the board, such as non-wet or solder bridge between the solder balls and the board (not shown).

[0034] Therefore, in an embodiment of the present invention, an open-type heat sink is proposed that can minimize the occurrence of warping in low and high temperature regions by increasing the fixing points between the semiconductor package and the heat sink while maintaining the structure of the open-type heat sink through a heat sink with modified fixing points on four sides and four openings.

[0035] FIG. 3 illustrates a semiconductor package according to an embodiment of the present invention.

[0036] 3(a) to 3(c), a semiconductor package 100 according to an embodiment includes a substrate 111 having a circuit pattern similar to a general substrate and a rectangular flat surface, and a silicon die 112 formed on the substrate 111 with an adhesive material such as epoxy or an adhesive film. The silicon die 112 may be electrically connected to the substrate 111 using a wire (not shown) or a flip chip bonding method.

[0037] The open-type heat sink includes a heat sink body 113 and a fixing module 114. The heat sink body 113 has an area equal to or larger than that of the substrate 111, and is placed on the top surface of the silicon die 112 to protect the silicon die 112.

[0038] For ease of explanation, in this embodiment of the present invention, the heat sink is shown to include a rectangular heat sink body 113, a plurality of fixed portions 114 of a certain length provided at the lower end of the heat sink body 113 and fixed to the substrate 111, and a plurality of open portions 115 that are not fixed to the substrate 111.

[0039] For convenience of explanation, in the embodiment of the present invention, the heat sink body 113 is described as being rectangular, but it may be embodied as a polygon as long as it is installed on the upper surface of the silicon die 112 and has an area equal to or larger than that of the substrate 111. And, the heat sink body 113 is described as being made of copper (Cu) coated with nickel (Ni), but there is no particular restriction on the material of the heat sink body 113.

[0040] TIFF0007646005000001.tif43168

[0041] Examples of the positions of the open portions of the above-mentioned open-type heat sink will be described with reference to Figs. 4a and 4b.

[0042] 4a and 4b are diagrams illustrating an open-type heat sink according to an embodiment of the present invention.

[0043] 4a, an open-type heat sink of a semiconductor package 100 according to an embodiment has a rectangular heat sink body 113 having an area equal to or larger than that of a substrate 111. Fixed portions 114, 114-1 to 114-4 of a certain length are formed in certain regions of the four sides of the heat sink body 113, and open portions 115, 115-1 to 115-4 are formed from the vertex of the heat sink body 113 to the side on which the fixed portion 114 is formed.

[0044] The fixing portion 114 is an area that comes into direct contact with the substrate 111, and is formed to a fixed length based on the center of each side of the heat sink body 113. In the embodiment of the present invention, the fixing portion 114 is formed to a fixed length based on the center of each side of the heat sink body 113, but may be formed close to one vertex. In the embodiment of the present invention, the fixing portion 114 is formed at four points on the heat sink body 113, but may be formed at more than four points.

[0045] The opening 115 does not contact the substrate 111, so that heat generated in the silicon die 112 is dissipated to the outside by natural convection. To this end, the opening 115 is spaced apart from the substrate 111 by a certain height.

[0046] At least one of the first opening 115-1 to the fourth opening 115-4 is an inlet through which wind generated by a cooling fan installed for forced convection flows in, and the remaining openings are outlets through which heat generated in the silicon die 112 is discharged together with the wind. For this reason, an example will be described in which the first opening 115-1 and the third opening 115-3 are embodied in a form facing each other, and the second opening 115-2 and the fourth opening 115-4 are embodied in a form facing each other. However, the length or position of the openings may be varied depending on the wind direction of the cooling fan installed for forced convection.

[0047] Taking the first open portion 115-1 as an example, a first portion of the first open portion 115-1 is connected to one side of the first fixed portion 114-1 and a second portion of the first open portion 115-1 is connected to one side of the second fixed portion 114-2, centered around the apex of the heat sink body 113. Similarly, the second open portion 115-2 to the fourth open portion 115-4 are formed in the same manner.

[0048] Here, the length of the fixed portion and the height of the open portion are not limited to any particular numerical value.

[0049] Meanwhile, as shown in FIG. 4b, in a semiconductor package 100 according to another embodiment, fixed portions 114, 114-5 to 114-8 of a certain length are formed based on the vertex portion of the heat sink body 113, and opening portions 115, 115-5 to 115-8 are formed in certain areas on the four sides of the heat sink body 113.

[0050] The openings 115, 115-5 to 115-8 are not in contact with the substrate 111, so that heat generated in the silicon die 112 is dissipated to the outside by natural convection. To this end, the openings 115 are implemented to be spaced apart from the substrate 111 by a certain height.

[0051] The openings 115 are formed to a fixed length based on the center of each side of the heat sink body 113. In the embodiment of the present invention, the openings 115 are formed to a fixed length based on the center of each side of the heat sink body 113 as an example, but they may be formed near one vertex.

[0052] The fixing portions 114, 114-5 to 114-8 are regions that come into direct contact with the substrate 111 and are formed to have a certain length based on the apex of the heat sink body 113. Taking the first fixing portion 114-5 as an example, the first fixing portion 114-5 is formed such that a first portion is connected to one side of the first opening 115-5 and a second portion of the first fixing portion 114-5 is connected to one side of the second opening 115-6, with the apex of the heat sink body 113 as the center. Similarly, the second fixing portion 114-6 to the fourth fixing portion 114-8 are also formed in the same shape.

[0053] The flow of heat in a semiconductor package including a heat sink implemented according to the above-described embodiment will be described with reference to Fig. 5. Fig. 5 illustrates an example in which a heat sink having an opening at the apex is included in a semiconductor package.

[0054] FIG. 5 is an exemplary view showing a heat flow in a heat sink according to an embodiment of the present invention.

[0055] TIFF0007646005000002.tif44168

[0056] In this way, the heat dissipation effect of the semiconductor chip can be improved by simultaneously applying natural convection and forced convection by a cooling fan by applying an open-type shape structure without changing the material and size of the heat sink.

[0057] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the claims also fall within the scope of the present invention.

Claims

1. The heat sink body has an area equal to or larger than that of the substrate, a contact area formed at the center of the heat sink body and indirectly contacting a silicon die formed on the substrate; a plurality of fixing portions formed on an outer periphery of the heat sink body and directly contacting the substrate; a heat sink body including a plurality of openings formed between the plurality of fixing parts on an outer periphery of the heat sink body, the openings defining a space of a predetermined height from the substrate;

2. The heat sink of claim 1 , wherein the heat sink body is embodied in a rectangular shape.

3. The heat sink according to claim 2 , wherein the fixing portions are formed on four sides of an outer periphery of the heat sink body.

4. The heat sink according to claim 3 , wherein the plurality of openings are formed at four vertices of an outer periphery of the heat sink body.

5. The heat sink according to claim 2 , wherein the fixing portions are formed at four vertices of an outer periphery of the heat sink body.

6. The heat sink according to claim 5 , wherein the plurality of openings are formed on four sides of an outer periphery of the heat sink body.

7. 2. The heat sink of claim 1, wherein at least one of the plurality of openings is an inlet through which air generated by a cooling fan flows in, and at least one of the plurality of openings is an outlet through which the inlet air is discharged together with heat from the silicon die.

8. The heat sink according to claim 7 , wherein the outlet releases heat generated in the silicon die to the outside by natural convection due to a temperature difference between the silicon die and a temperature around the silicon die.

9. a substrate having a circuit pattern and being a rectangular flat surface; a silicon die formed on and in electrical communication with the substrate; a heat sink formed on the silicon die for dissipating heat generated from the silicon die to the outside; The heat sink includes a plurality of fixing portions formed by directly contacting the substrate for a certain length based on four vertices of the outer periphery of the heat sink or a portion of the lengths of the four sides, and a plurality of openings formed between each fixing portion and spaced a certain height from the substrate, for a semiconductor package.

10. The semiconductor package of claim 9 , further comprising a cooling fan configured to blow air into any one of the plurality of openings.

11. The heat sink, heat generated in the silicon die is released to the outside by natural convection through a contact area that directly or indirectly contacts the silicon die due to a temperature difference between the silicon die and the surrounding area of ​​the silicon die; The semiconductor package of claim 9 , wherein air flowing into at least one of the plurality of openings is discharged together with heat of the silicon die through the at least one of the plurality of openings.

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