JP2019050239A - Semiconductor package - Google Patents

Abstract

To provide a semiconductor package which is excellent in heat dissipation and has high shock resistance.SOLUTION: A semiconductor package includes a wiring board, a semiconductor element disposed on one principal plane of the wiring board, and a case covering the semiconductor element and connected to the wiring board. In the semiconductor package, the case is a vapor chamber configured with a planar housing having an internal space, a wick disposed in the internal space, and a working medium contained in the internal space.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a semiconductor package.

  Semiconductor devices such as CPUs (central processing units) are generally housed in a metal case for protection of the devices and handled as a semiconductor package. In addition, since the semiconductor element is exothermic, the semiconductor package is required to have high heat dissipation.

  For example, Patent Document 1 discloses a semiconductor package in which a semiconductor element and a metal case are thermally connected by a good heat conductive member such as a metal member. There is also known a semiconductor package in which the thermal connection between the semiconductor element and the metal case is made by thermal grease.

JP 2001-298131 A

  A conventional semiconductor package uses a metal case to improve heat dissipation, but it can not be said that a simple metal plate is sufficient to satisfy the demand for heat dissipation improvement that is gradually increasing. In addition, since the metal case formed of a metal plate generally has high rigidity, if an impact is applied to the metal case at the time of mounting the semiconductor package, etc., the impact is directly transmitted to other parts. As a result, there is a possibility that the semiconductor element may be damaged or the junction between the members may be disconnected.

  Accordingly, an object of the present invention is to provide a semiconductor package having excellent heat dissipation and high impact resistance.

  As a result of intensive studies to solve the above problems, the present inventors can improve heat dissipation and further improve impact resistance by using a flat-shaped vapor chamber instead of the metal case. It came to create the present invention.

According to the summary of the present invention,
Wiring board,
A semiconductor element disposed on one main surface of the wiring board;
A semiconductor package comprising: a case which covers the semiconductor element and is joined to the wiring board;
The semiconductor package according to claim 1, wherein the case is a vapor chamber having a planar casing having an internal space, a wick disposed in the internal space, and a working medium enclosed in the internal space. Provided.

  According to the present invention, there is provided a semiconductor package comprising: a wiring board; a semiconductor element disposed on one of the main surfaces of the wiring board; and a case covering the semiconductor element and joined to the wiring board; Heat dissipation is achieved by forming a flat vapor chamber comprising a planar casing having a space, a wick disposed in the internal space, and a working medium enclosed in the internal space. And a semiconductor package with improved impact resistance.

FIG. 1 is a cross-sectional view of a semiconductor package 1a according to an embodiment of the present invention. FIG. 2 is a plan view of the semiconductor package 1a shown in FIG. FIG. 3 is a cross-sectional view of a baber chamber used for the semiconductor package 1a shown in FIG. FIG. 4 is a cross-sectional view of a semiconductor package 1b according to another embodiment of the present invention. FIG. 5 is a cross-sectional view of a semiconductor package 1c according to another embodiment of the present invention. FIG. 6 is a perspective view of a semiconductor package 1 d according to another embodiment of the present invention.

  Hereinafter, the semiconductor package of the present invention will be described in detail.

(Embodiment 1)
A cross-sectional view of a semiconductor package 1a of the present embodiment is shown in FIG. 1, and a plan view is shown in FIG. Further, FIG. 3 shows a cross-sectional view of the baber chamber 3 used for the semiconductor package of the present invention.

  As shown in FIGS. 1 and 2, the semiconductor package 1 a of the present embodiment includes a semiconductor element 2, a vapor chamber (case) 3, and a wiring board 4. In the semiconductor package 1 a, the semiconductor element 2 is disposed on one main surface of the wiring board 4, and the vapor chamber 3 is further disposed thereon so as to cover the semiconductor element 2. That is, the vapor chamber 3 plays the role of a case. The vapor chamber 3 has flexibility and is joined to the wiring board 4 at a joint 24 located at the edge thereof. The joint 24 is formed on the entire edge of the vapor chamber 3. That is, the semiconductor package 1a of the present embodiment has a shape in which the central portion where the semiconductor element 2 is located is raised, and the top thereof, that is, the portion where the semiconductor element 2 is located in plan view is planar. As shown in FIG. 3, the vapor chamber 3 includes a planar casing 11 having an internal space 13, a wick 12 disposed in the internal space, and a working medium enclosed in the internal space. To have Further, the vapor chamber 3 has an operating area 21 consisting of an internal space in which a working medium is enclosed and a semi-operating area 22 formed around the operating area in plan view.

  The semiconductor package according to the present invention is very high in thermal conductivity as compared with the case composed of a conventional metal plate because the case is composed of the vapor chamber. Therefore, the heat generated in the semiconductor element can be efficiently diffused and dissipated. In addition, the vapor chamber has cushioning properties due to the presence of the internal space, and since the casing has flexibility, flexibility, and the like, it is excellent in impact resistance. The semiconductor package of the present invention, which is excellent in impact resistance, may damage the semiconductor element due to an impact or drop the semiconductor element from the wiring board when attaching it to another electronic component or attaching a radiation fin or the like. It can be prevented.

  Further, as shown in FIG. 1 and FIG. 2, in the semiconductor package 1a of the present embodiment, the vapor chamber 3 is curved toward the wiring board 4 in a part of the semi-operation area 22 and the wiring board 4 is Bonded to. Therefore, a space 5 is formed between the side surface of the semiconductor element 2 and the vapor chamber 3. The semiconductor package 1a has high impact resistance because high flexibility is obtained by the flexibility of the space 5 and the vapor chamber 3.

  The semiconductor element 2 is not particularly limited, and examples thereof include heat-generating semiconductor integrated circuits such as an accelerated processing unit (APU), a central processing unit (CPU), a power management integrated circuit (PMIC), and a memory.

  In the semiconductor package 1a of the present embodiment, the number of semiconductor elements 2 disposed on the wiring board 4 is one, but the present invention is not particularly limited to this aspect. For example, two or more semiconductor elements 2 may be present on the wiring board 4 and these may be covered by one vapor chamber 3.

  The wiring board 4 is not particularly limited as long as it is a wiring board used for a semiconductor package, and preferably a printed wiring board is used.

  The vapor chamber 3 comprises a planar casing 11 having an internal space 13, a wick 12 disposed in the internal space, and a working medium enclosed in the internal space. Here, “planar” includes plate-like and sheet-like shapes, and a shape whose length and width are considerably large with respect to height (thickness), for example, the length and width are 10 or more times the thickness, It means a shape that is preferably 100 times or more.

In a preferred embodiment, as shown in FIG.
A housing 11 comprising opposing first and second sheets 16 and 17 to which the outer edge portion 23 is joined;
A pillar 18 provided between the first sheet 16 and the second sheet 17 so as to support them from the inside;
A wick 12 disposed in the internal space 13 of the housing 11;
And a working medium enclosed in the internal space 13 of the housing 11.

  The vapor chamber 3 has an operating area 21 consisting of an internal space in which a working medium is enclosed and a semi-operating area 22 formed around the operating area in plan view. Typically, the semi-working area corresponds to the outer edge 23 where the first and second sheets are joined. The working area is an area that functions as a vapor chamber, and thus has a very high heat transfer capability. Therefore, it is preferable to set the working area as wide as possible. On the other hand, the semi-operation area is not an area that exhibits a function as a vapor chamber, but is formed of a material having high thermal conductivity, so it has a certain degree of heat transport capability. Moreover, since the semi-operation area is in the form of a sheet, it is excellent in durability, flexibility, and processability. Therefore, it is preferable to perform bonding with the wiring board in the semi-operation area.

  The planar dimensions of the vapor chamber 3 are not particularly limited, but it is preferable that the dimensions be as close as possible to the dimensions of the wiring board 4. That is, the distance from the edge of the vapor chamber 3 to the edge of the wiring board 4 is preferably as small as possible, for example 10 mm or less, more preferably 5 mm or less, still more preferably 3 mm or less, still more preferably 1 mm or less obtain. In one aspect, the planar dimension of the vapor chamber 3 is substantially the same as the planar dimension of the wiring board 4. By making the planar dimension of the vapor chamber 3 larger, the heat dissipation effect is further improved.

  As described above, the vapor chamber 3 is bonded to the wiring board 4 at the bonding portion 24 located at the edge thereof. The width of the bonding portion 4 is not particularly limited as long as it can fix the vapor chamber 3, but may be, for example, 0.5 mm to 20 mm, preferably 1 mm to 10 mm, and more preferably 1 mm to 6 mm.

  The thickness of the vapor chamber 3 is preferably 100 μm to 600 μm, and more preferably 200 μm to 500 μm.

  The materials constituting the first sheet 16 and the second sheet 17 are not particularly limited as long as they have properties suitable for use as a vapor chamber, such as thermal conductivity, strength, flexibility, flexibility and the like. . The material constituting the first sheet 16 and the second sheet 17 is preferably a metal, for example, copper, nickel, aluminum, magnesium, titanium, iron, or an alloy containing them as a main component, and particularly preferably It may be copper. The materials constituting the first sheet 16 and the second sheet 17 may be the same or different, but are preferably the same.

  One or both of the first sheet and the second sheet have a plurality of projections 19 or columns 18, or projections 19 and columns 18 on the main surface on the inner space side. By the sheet having such a plurality of projections and / or columns, the working medium can be held between the projections, and it becomes easy to increase the amount of the working medium of the vapor chamber of the present invention. The heat transport capacity of the vapor chamber is improved by increasing the amount of working medium. Here, the convex portion and / or the pillar means a portion relatively higher in height than the periphery, and in addition to the portion protruding from the main surface, a concave portion formed on the main surface, for example, a groove or the like is relatively used. It also includes parts where the height is high.

  The height of the column 18 is larger than the height of the convex portion 19. In one aspect, the height of the pillars 18 is preferably 1.5 times to 100 times, more preferably 2 times to 50 times, more preferably 3 times to 20 times the height of the convex portions 19. It may be twice or less, still more preferably 3 to 10 times.

  The height of the convex portion 19 is not particularly limited, but may be preferably 1 μm to 100 μm, more preferably 5 μm to 50 μm, and still more preferably 15 μm to 30 μm. By making the height of the convex portion higher, the holding amount of the working medium can be increased. Further, by making the height of the convex portion lower, it is possible to secure a wider space for the vapor of the working medium to move. Therefore, the heat transport capacity of the vapor chamber can be adjusted by adjusting the height of the convex portion.

  The distance between the convex portions 19 is not particularly limited, but may be preferably 1 μm to 500 μm, more preferably 5 μm to 300 μm, and still more preferably 15 μm to 150 μm. By reducing the distance between the projections, the capillary force can be further increased. Moreover, the transmittance can be further increased by increasing the distance between the convex portions.

  The shape of the convex portion 19 is not particularly limited, but may be a cylindrical shape, a prismatic shape, a truncated cone shape, a truncated pyramid shape, or the like. Further, the shape of the convex portion 7 may be a wall shape, that is, a shape in which a groove is formed between adjacent convex portions.

  In the vapor chamber used in the present invention, the convex portion 19 is not an essential component, and may not exist.

  The pillars 18 support the first sheet 16 and the second sheet 17 from the inside so that the distance between the first sheet and the second sheet becomes a predetermined distance. By installing the column 18 inside the housing 11, when the pressure inside the housing is reduced, deformation of the housing can be suppressed, for example, when external pressure from the outside of the housing is applied.

  The material for forming the columns 18 is not particularly limited, but is, for example, a metal, for example, copper, nickel, aluminum, magnesium, titanium, iron, or an alloy containing them as a main component, and particularly preferably copper. obtain. In a preferred embodiment, the material forming the columns is the same material as either or both of the first sheet and the second sheet.

  The height of the pillars 18 can be appropriately set according to the desired thickness of the vapor chamber, and is preferably 50 μm to 500 μm, more preferably 100 μm to 400 μm, and still more preferably 100 μm to 200 μm, for example 125 μm 150 μm or less. Here, the height of the pillar means the height in the thickness direction of the vapor chamber (the height in the vertical direction in FIG. 3).

  The shape of the column 18 is not particularly limited, but may be a cylindrical shape, a prismatic shape, a truncated cone shape, a truncated pyramid shape, or the like.

  The thickness of the column 18 is not particularly limited as long as it gives the strength capable of suppressing the deformation of the casing of the vapor chamber. For example, the circle equivalent diameter of the cross section perpendicular to the height direction of the column is 100 μm or more and 2000 μm or less Preferably, it is 300 micrometers or more and 1000 micrometers or less. The deformation of the casing of the vapor chamber can be further suppressed by increasing the circle equivalent diameter of the column. Further, by reducing the circle equivalent diameter of the pillars, it is possible to secure a wider space for moving the working medium vapor.

  The arrangement of the pillars 18 is not particularly limited, but is preferably arranged evenly, for example, in a lattice point so that the distance between the pillars becomes constant. By evenly arranging the columns, it is possible to ensure uniform strength throughout the vapor chamber.

The number and interval of the pillars 18 are not particularly limited, but preferably 0.125 or more and 0.5 or less, more preferably, per 1 mm ² of the main surface area of one sheet defining the internal space of the vapor chamber. It may be 0.2 or more and 0.3 or less. By increasing the number of pillars, deformation of the vapor chamber (or housing) can be further suppressed. Further, by reducing the number of pillars, it is possible to secure a wider space for moving the working medium vapor.

  The pillars 18 may be integrally formed with the first sheet or the second sheet, or may be manufactured separately from the first sheet or the second sheet and then fixed in place.

  The wick 12 is not particularly limited as long as it has a structure capable of moving the working medium by capillary force. The capillary structure that exerts the capillary force for moving the working medium is not particularly limited, and may be a known structure used in a conventional vapor chamber. For example, the capillary structure may be a fine structure having irregularities such as pores, grooves, and protrusions, such as a fiber structure, a groove structure, and a mesh structure.

  The thickness of the wick 12 is not particularly limited, but may be, for example, 5 μm to 200 μm, preferably 10 μm to 80 μm, and more preferably 30 μm to 50 μm.

  Although the size and shape of the wick 12 are not particularly limited, for example, it is preferable to have a size and shape that can be continuously installed from the evaporation portion to the condensation portion inside the housing.

  In FIG. 3, the wick 12 is one independent member, but may be integrally formed with the housing. For example, without providing the wick 12 in the baber chamber shown in FIG. 3, the convex portion 19 formed on the wall surface of the housing can be used as the wick.

  The working medium is not particularly limited as long as it can cause a gas-liquid phase change under the environment in the housing, and, for example, water, alcohols, chlorofluorocarbons, etc. can be used. In one embodiment, the working medium is an aqueous compound, preferably water.

  In the semiconductor package 1 a of the present embodiment, in the vapor chamber 3, the operation region 21 is disposed on the semiconductor element 2, and the semiconductor element 2 and the vapor chamber 3 are thermally connected. The thermal connection between the semiconductor element 2 and the vapor chamber 3 may be performed by bringing the two into direct contact with each other, or may be performed via another thermally conductive member, for example, a metallic member such as thermal grease or solder. Here, the "thermal grease" is a viscous substance having high thermal conductivity, and for example, one in which particles of metal or metal oxide having high thermal conductivity are dispersed in modified silicone or the like is used.

  When the semiconductor element 2 and the vapor chamber 3 are thermally connected via another thermally conductive member, for example, a metallic member such as thermal grease or solder, a thermal connection equal to or higher than in the case of direct contact between the two Connection can be made. This is because in the configuration in which the semiconductor element 2 and the vapor chamber 3 are in direct contact, a small gap may occur between them. If both are thermally connected via thermal grease, solder or the like, even if a gap is generated between the semiconductor element 2 and the vapor chamber 3, it can be filled with thermal grease, solder or the like. Therefore, thermal connection equal to or more than that in the case where the semiconductor element 2 and the vapor chamber 3 are in direct contact can be performed.

  In one aspect, the top surface of the semiconductor element 2 and the working area 21 of the vapor chamber 3 are bonded. The bonding method is not particularly limited, and welding (for example, resistance welding, laser welding), ultrasonic bonding, bonding by solder, an adhesive, etc. may be mentioned.

  In one embodiment, the vapor chamber 3 is bonded to the circuit board 4 in the semi-working area 22. The bonding method is not particularly limited, and welding (for example, resistance welding, laser welding), ultrasonic bonding, bonding by solder, an adhesive, etc. may be mentioned.

Second Embodiment
A cross-sectional view of the semiconductor package 1b of the present embodiment is shown in FIG. The internal structure of the vapor chamber 3 is omitted for simplicity.

  As shown in FIG. 4, in the semiconductor package 1 b of this embodiment, the internal space 3 of the vapor chamber 3 exists over the entire top surface of the semiconductor element 2. That is, the working area of the vapor chamber 3 covers the entire top surface of the semiconductor element 2. Furthermore, the working area may extend beyond the edge of the top surface of the semiconductor element 2 and may be gently bent downward. The vapor chamber 3 is joined at the edge which is the semi-working area. By arranging the operating region to cover the entire top surface of the semiconductor element as described above, the heat dissipation and impact resistance are further improved.

  Further, in the present embodiment, the thermal connection between the semiconductor element 2 and the vapor chamber 3 is performed using the thermal grease 25. Heat dissipation is further improved by using thermal grease.

  In the present invention, the thermal connection between the semiconductor element 2 and the vapor chamber 3 is preferably by the thermal grease 25, but is not limited thereto. For example, the thermal connection between the semiconductor element 2 and the vapor chamber 3 may be a thermal connection by direct contact, a thermal connection by using a metal member such as solder, or a thermal connection by bonding.

(Embodiment 3)
A cross-sectional view of the semiconductor package 1c of the present embodiment is shown in FIG. The internal structure of the vapor chamber 3 is omitted for simplicity.

  As shown in FIG. 5, in the semiconductor package 1 c of the present embodiment, the operation region 21 extends from the top surface of the semiconductor element 2 to the side surface, and heat is applied to both the top and side surfaces of the semiconductor element 2. Are placed in a state of being connected. That is, in the semiconductor package 1c, the operation area is arranged to cover the top surface and the side surface of the semiconductor element. Therefore, in the semiconductor package 1c, no space like the space 5 in the semiconductor packages 1a and 1b exists between the side surface of the semiconductor element 2 and the vapor chamber 3. As a result, the heat of the side surface of the semiconductor element 2 is directly transferred to the vapor chamber 3, so the semiconductor package 1c has higher heat dissipation.

  In the present embodiment, the working region of the vapor chamber 3 may extend from the top surface of the semiconductor element 2 to the wiring board 4 beyond the side surface.

(Embodiment 4)
A perspective view of a semiconductor package 1d of the present embodiment is shown in FIG.

  As shown in FIG. 6, the semiconductor package of the present invention may further have a radiation fin 26 on the vapor chamber 3 (case). Although not shown in FIG. 6, a semiconductor element is disposed on the wiring board 4, and the semiconductor element is covered by the vapor chamber 3. That is, the semiconductor element 2 is present inside the raised portion of the vapor chamber 3. The radiation fin 26 and the vapor chamber 3 are thermally connected. By providing the heat dissipating fins, the heat generated in the semiconductor element is transferred to the vapor chamber and further transferred to the heat dissipating fins having a large surface area, so that the heat dissipation is further improved.

  In the present embodiment, the configurations of the semiconductor element 2, the vapor chamber 3 and the wiring board 4 are not particularly limited, but preferably the configurations shown in the first to third embodiments. Particularly preferably, the semiconductor package 1d has the configuration of the semiconductor package 1c shown in FIG. That is, the semiconductor package 1d has a configuration in which a radiation fin is attached to the upper portion of the semiconductor package 1c shown in FIG. By incorporating the configuration of the semiconductor package 1c, the working region of the vapor chamber 3 is also present on the side surface of the semiconductor element 2, so the heat of the side surface of the semiconductor element is rapidly transmitted to the radiation fin 26 located on the top surface. be able to. As a result, the semiconductor package 1d in the present embodiment can dissipate heat more efficiently.

  As said radiation fin, well-known fins, such as various fins, such as a corrugated fin, an offset fin, a waving fin, a slit fin, a folding fin, can be used.

  The thermal connection between the radiation fin 26 and the vapor chamber 3 may be performed by bringing the two into direct contact with each other, or may be performed via another thermally conductive member, for example, a metal member such as thermal grease or solder. .

  When thermal connection between the radiation fin 26 and the vapor chamber 3 is made through another thermally conductive member such as a thermal grease, a metal member such as solder, etc., the thermal resistance is equal to or higher than in the case of direct contact between the two. Connection can be made. This is because in the configuration in which the radiation fin 26 and the vapor chamber 3 are in direct contact, a small gap may be generated therebetween. If the two are thermally connected via thermal grease, solder or the like, thermal grease, solder or the like can be filled even if a gap is generated between the radiation fin 26 and the vapor chamber 3. Therefore, thermal connection equal to or more than that in the case where the heat dissipating fins 26 and the vapor chamber 3 are in direct contact can be made.

  Although the semiconductor package of the present invention has been described with reference to several embodiments, the present invention is not limited to the above semiconductor package, and design changes can be made without departing from the scope of the present invention.

Although the present invention is not particularly limited, the following aspects are disclosed.
1. Wiring board,
A semiconductor element disposed on one main surface of the wiring board;
A semiconductor package comprising: a case which covers the semiconductor element and is joined to the wiring board;
The semiconductor package is a vapor chamber comprising a planar casing having an internal space, a wick disposed in the internal space, and a working medium enclosed in the internal space.
2. The vapor chamber has an operation area including the inner space in plan view and a semi-operation area formed around the operation area, and the operation area is positioned on the top surface of the semiconductor device. The semiconductor package according to claim 1, wherein the semi-operation area is bonded to the wiring board.
3. The semiconductor package according to aspect 1, wherein the operation region is located on a side surface of the semiconductor device.
4. The semiconductor package according to any one of Aspects 1 to 3, wherein the operation region covers the entire top surface of the semiconductor element.
5. Aspect 7. The semiconductor package according to any one of aspects 1 to 4, further comprising a radiation fin on the case.

  The semiconductor package of the present invention can be suitably used in various applications because of its high heat dissipation and impact resistance.

DESCRIPTION OF SYMBOLS 1a, 1b, 1c ... semiconductor package 2 ... semiconductor element, 3 ... vapor chamber (case), 4 ... wiring board, 5 ... space 11 ... case 12, 12 wick, 13 ... internal space, 16 ... 1st sheet, 17 2nd sheet 18 pillar 19 convex portion 21 actuation region 22 semi-operation region 23 outer edge portion 24 junction portion 25 thermal grease 26 radiation fin

Claims (5)

Wiring board,
A semiconductor element disposed on one main surface of the wiring board;
A semiconductor package comprising: a case which covers the semiconductor element and is joined to the wiring board;
The semiconductor package is a vapor chamber comprising a planar casing having an internal space, a wick disposed in the internal space, and a working medium enclosed in the internal space.   The vapor chamber has an operation area including the inner space in plan view and a semi-operation area formed around the operation area, and the operation area is positioned on the top surface of the semiconductor device. The semiconductor package according to claim 1, wherein the semi-operation area is bonded to the wiring board.   The semiconductor package according to claim 2, wherein the operation region is located on a side surface of the semiconductor device.   The semiconductor package according to any one of claims 1 to 3, wherein the operation region covers the entire top surface of the semiconductor element.   The semiconductor package according to any one of claims 1 to 4, further comprising a radiation fin on the case.

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