JP2017152606A - Heat radiation substrate, semiconductor package using the same, and semiconductor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor package which enables reduction of warpage of a heat radiation substrate and achieves excellent heat radiation performance, and to provide a semiconductor device.SOLUTION: A heat radiation substrate 100 includes: a first metal layer 1; a second metal layer 2 and a third metal layer 3 joined to the first metal layer 1; a fourth metal layer 4 joined to the second metal layer 2; and a fifth metal layer 5 joined to the third metal layer 3. First through holes 2a are provided at the second metal layer 2. Second through holes 3a are provided at the third metal layer 3. In a plan view, a centroid of each of the multiple first through holes 2a is offset from a centroid of each of the second through holes 3a.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a heat dissipation substrate for dissipating heat generated from a semiconductor element such as a power semiconductor element, a semiconductor package using the heat dissipation substrate, and a semiconductor module.

  As described in Patent Document 1, a heat dissipation board for dissipating heat generated from a semiconductor chip for power supply includes a high thermal conductive layer of copper or a copper alloy and a low thermal expansion layer of an Fe-Ni alloy alternately. A plurality of high thermal conductive layers that are laminated to each other and sandwich the low thermal expansion layer are continuous through a plurality of through holes formed in the low thermal expansion layer.

JP-A-10-173109

  The conventional heat dissipation board has a problem that the heat dissipation board may be warped due to a difference in thermal expansion coefficient between copper or a copper alloy and an Fe—Ni alloy, and the heat dissipation performance to the outside tends to decrease. .

The heat dissipation board of the embodiment of the present invention is
A first metal layer;
A second metal layer bonded to the first surface of the first metal layer, the second metal layer provided with a plurality of first through holes penetrating in the thickness direction;
A third metal layer bonded to a second surface of the first metal layer opposite to the first surface, the third metal layer having a plurality of second through holes penetrating in the thickness direction; ,
A fourth metal layer bonded to a surface of the second metal layer opposite to a surface bonded to the first surface of the first metal layer;
A fifth metal layer bonded to a surface of the third metal layer opposite to a surface bonded to the second surface of the first metal layer;
A metal member filled in the plurality of first through holes and the plurality of second through holes,
The first metal layer, the fourth metal layer, and the fifth metal layer have Young's moduli smaller than Young's moduli of the second metal layer and the third metal layer,
The centroids of the plurality of first through holes and the centroids of the plurality of second through holes are shifted in plan view.

Moreover, the semiconductor package of the embodiment of the present invention includes the above heat dissipation substrate,
A frame made of an insulator fixed to the fourth metal layer of the heat dissipation substrate;
And a power supply terminal attached to the frame.

A semiconductor device according to an embodiment of the present invention includes the semiconductor package described above.
And a semiconductor element mounted on the semiconductor package.

According to the heat dissipation substrate of the embodiment of the present invention, when the heat dissipation substrate is heated by the heat generated from the semiconductor element, the warpage of the heat dissipation substrate can be suppressed.

  In addition, according to the semiconductor package of the embodiment of the present invention, by providing the heat dissipation substrate, it is possible to suppress a decrease in heat dissipation due to warpage of the heat dissipation substrate.

  Further, according to the semiconductor device of the embodiment of the present invention, by providing the above-described semiconductor package, heat generated from the semiconductor element can be dissipated well, and high reliability can be realized.

It is a perspective view of the thermal radiation board concerning the embodiment of the present invention. (A) is sectional drawing of the thermal radiation board | substrate in the AA line of FIG. 1, (b) is the partial expanded sectional perspective view of (a). It is a disassembled perspective view of the thermal radiation board which concerns on embodiment of this invention. It is a top view which shows one aspect | mode of each metal layer which comprises a heat sink. It is a top view which shows the other aspect of each metal layer which comprises a heat sink. 1 is a perspective view showing a semiconductor package according to an embodiment of the present invention. 1 is a perspective view showing a semiconductor device according to an embodiment of the present invention.

  A heat dissipation board, a semiconductor package, and a semiconductor device according to embodiments of the present invention will be described in detail below.

  FIG. 1 is a perspective view of a heat dissipation board according to an embodiment of the present invention. 2A is a cross-sectional view of the heat dissipation board taken along line AA in FIG. 1, and FIG. 2B is a partially enlarged cross-sectional perspective view of FIG. FIG. 3 is an exploded perspective view of the heat dissipation board according to the embodiment of the present invention. FIG. 4 is a plan view of each metal layer constituting the heat dissipation substrate according to the embodiment of the present invention. FIG. 5 is a plan view of each metal layer constituting a heat dissipation board according to another embodiment of the present invention. FIG. 6 is a perspective view showing a semiconductor package according to the embodiment of the present invention. FIG. 7 is a perspective view showing a semiconductor device according to the embodiment of the present invention.

  The heat dissipation substrate 100 includes a first metal layer 1, a second metal layer 2, a third metal layer 3, a fourth metal layer 4, a fifth metal layer 5, and a metal member 6.

  The first metal layer 1 has a first surface 1a and a second surface 1b opposite to the first surface. The second metal layer 2 is bonded to the first surface 1a, and the third metal layer 3 is bonded to the second surface 1b. Further, the fourth metal layer 4 is bonded to the surface of the second metal layer 2 opposite to the surface bonded to the first surface 1 a of the first metal layer 1. The fifth metal layer 5 is bonded to the surface of the third metal layer 3 opposite to the surface bonded to the second surface 1 b of the first metal layer 1. That is, as shown in FIG. 3, the heat dissipation substrate 100 according to the embodiment of the present invention includes a fifth metal layer 5, a third metal layer 3, a first metal layer 1, a second metal layer 2, and a fourth metal layer 4. However, it has the structure laminated | stacked one by one.

  The Young's modulus of the first metal layer 1, the fourth metal layer 4, and the fifth metal layer 5 is smaller than the Young's modulus of the second metal layer 2 and the third metal layer 3. The first metal layer 1, the fourth metal layer 4, and the fifth metal layer 5 only have to have a Young's modulus smaller than that of the second metal layer 2 and the third metal layer 3. The layer 1, the fourth metal layer 4, and the fifth metal layer 5 may have the same Young's modulus or different Young's moduli. The second metal layer 2 and the third metal layer 3 only have to have a larger Young's modulus than the first metal layer 1, the fourth metal layer 4, and the fifth metal layer 5. The layer 2 and the third metal layer 3 may have the same Young's modulus or different Young's moduli.

  Further, the first metal layer 1, the fourth metal layer 4, the fifth metal layer 5, and the metal member 6 have a thermal conductivity larger than that of the second metal layer 2 and the third metal layer 3. Things are used. Further, the thermal expansion coefficients of the first metal layer 1, the fourth metal layer 4, the fifth metal layer 5, and the metal member 6 are larger than the thermal expansion coefficients of the second metal layer 2 and the third metal layer 3.

  Examples of the first metal layer 1, the fourth metal layer 4, the fifth metal layer 5, and the metal member 6 include, for example, metal materials such as copper, silver, aluminum (Al), gold (Au), or the like. The thing formed from the alloy is mentioned. In the present embodiment, the first metal layer 1, the fourth metal layer 4, and the fifth metal layer 5 are made of copper or an alloy containing copper.

  The second metal layer 2 and the third metal layer 3 are formed of a metal material such as molybdenum (Mo) or tungsten (W), or an alloy thereof (copper-molybdenum sintered body, copper-tungsten sintered body, etc.). May be. In the present embodiment, the second metal layer 2 and the third metal layer 3 are made of molybdenum or an alloy containing molybdenum.

  The first metal layer 1, the fourth metal layer 4, and the fifth metal layer 5 may have the same thickness or different thicknesses. Further, the second metal layer 2 and the third metal layer 3 may have the same thickness or different thicknesses. The first metal layer 1, the fourth metal layer 4, and the fifth metal layer 5 are made of the same material and have the same thickness, and the second metal layer 2 and the third metal layer 3 are made of the same material and have the same thickness. More preferably. Thereby, the curvature and deformation | transformation of the thermal radiation board | substrate 100 which arise when heat is applied to the thermal radiation board | substrate 100 are suppressed.

  In the heat dissipation substrate 100 according to the embodiment of the present invention, the first metal layer 1, the fourth metal layer 4, and the fifth metal layer 5 are thicker than the thicknesses of the second metal layer 2 and the third metal layer 3. And have the same outer shape in plan view. For example, in plan view, the first metal layer 1, the fourth metal layer 4, and the fifth metal layer 5 have a long side of 5 mm to 30 mm and a short side of 4 mm to 28 mm. The thickness is 0.2 mm to 2 mm. The second metal layer 2 and the third metal layer 3 have a long side of 5 mm to 30 mm and a short side of 4 mm to 28 mm in plan view. The thickness is 0.1 mm to 1 mm. More specifically, for example, the thickness of the first metal layer 1 is 0.2 mm, the thickness of the fourth metal layer 4 and the fifth metal layer 5 is 0.3 mm, and the thickness of the second metal layer 2 and the third metal layer 3. May be 0.1 mm.

  As shown in FIGS. 2B and 3, the second metal layer 2 is provided with a plurality of first through holes 2 a penetrating the second metal layer 2 in the thickness direction. A plurality of second through holes 3a penetrating the third metal layer 3 in the thickness direction are provided.

  The opening shape of the first through hole 2a and the second through hole 3a may be, for example, a circular shape, an oval shape, an oval shape, a square shape, a rectangular shape, or other shapes. In the heat dissipation substrate 100 of the embodiment of the present invention, the opening shape of the first through hole 2a and the second through hole 3a is a circular shape, an elliptical shape, or an oval shape. By making the first through hole 2a and the second through hole 3a circular, the stress generated in the first through hole 2a and the second through hole 3a by the heat applied to the heat dissipation substrate 100 becomes symmetric with respect to the central axis, It becomes difficult to be partially biased.

  The plurality of first through holes 2a may have the same area as each other in a plan view or may have different areas. The plurality of second through holes 3a may also have the same area or different areas in plan view. If the areas of the plurality of first through holes 2a and the plurality of second through holes 3a are equal to each other in plan view, each of the first through holes 2a and the second through holes 3a is caused by heat applied to the heat dissipation substrate 100. The stress generated in the film tends to be uniform.

  The first through hole 2a has a circular shape with a diameter of 0.5 mm to 2 mm, or an elliptical shape with a major axis of 0.5 mm to 2 mm and a minor axis of 0.4 mm to 1.8 mm, and a major axis in plan view, for example. It has an oval shape with a length in the direction of 0.5 mm to 2 mm and a length in the minor axis direction of 0.4 mm to 1.8 mm.

  When the opening shape of the 1st through-hole 2a or the 2nd through-hole 3a is an ellipse shape or an ellipse shape, the long-side direction of the thermal radiation board | substrate 100 and the major axis direction of the 1st through-hole 2a or the 2nd through-hole 3a It is preferable to arrange them in parallel. In the long side direction, the second metal layer 2 or the third metal layer 3 between the first through hole 2a or the second through hole 3a and the first through hole 2a or the second through hole 3a adjacent thereto is continuous. Arranged. That is, the first through hole 2a or the second through hole 3a is continuous from one side to the other side without traversing the first through hole 2a or the second through hole 3a in the long side direction, whereas the first through hole 2a or the second through hole 3a is formed in the short side direction. There are many cases of crossing. For this reason, bending stress in the long side direction becomes strong, and warping and deformation in the long side direction are suppressed.

  As shown in FIGS. 2B and 3, the first through hole 2 a and the second through hole 3 a are filled with a metal member 6. The metal member 6 is preferably made of a metal having excellent thermal conductivity such as copper, silver, aluminum (Al), gold (Au), or an alloy thereof.

  The metal member 6 may be formed of the same material as any of the first metal layer 1, the fourth metal layer 4, and the fifth metal layer 5, and the first metal layer 1, the fourth metal layer 4, and the fifth metal layer 6 may be formed. The metal layer 5 may be made of a different material. Moreover, the metal member with which the 1st through-hole 2a is filled and the metal member with which the 2nd through-hole 3a is filled may be formed from the same material, and may be formed from a different material. In the present embodiment, the metal member filled in the first through hole 2a and the metal member filled in the second through hole 3a are the first metal layer 1, the fourth metal layer 4, and the fifth metal layer 5. Made of copper or an alloy containing copper.

  Further, in the heat dissipation substrate 100 of the present embodiment, as shown in FIGS. 4 and 5, the plurality of first through holes 2 a and the plurality of second through holes 3 a are formed of the plurality of first through holes 2 a in a plan view. Each centroid and each centroid of the plurality of second through holes 3a are arranged so as to be shifted from each other. The centroid means the position of the center of gravity of the inner plane of the first through hole 2a and the second through hole 3a. Hereinafter, unless otherwise specified, the description of the positions of the first through hole 2a and the second through hole 3a is based on the centroid.

  If the first through hole 2a and the second through hole 3a are arranged so that the centroids coincide with each other, the heat dissipation substrate 100 where the first through hole 2a and the second through hole 3a exist is changed from one surface to the other surface. A portion where the second metal layer 2 or the third metal layer 3 does not exist is formed in the cross section. The heat dissipation substrate 100 according to the embodiment of the present invention has a structure in which at least the second metal layer 2 or the third metal layer 3 is disposed in a cross section from one surface of the heat dissipation substrate 100 to the other surface. be able to. As a result, warpage and deformation of the heat dissipation substrate 100 can be reduced.

  The heat dissipation substrate 100 is used in a state where the surface of the fifth metal layer 5 opposite to the surface bonded to the third metal layer 3 is in contact with an external heat dissipation body such as an external substrate (not shown). Therefore, when the heat dissipation substrate 100 is warped, the contact area between the heat dissipation substrate 100 and the external substrate is reduced, and the heat dissipation performance is deteriorated. According to the heat dissipation substrate 100 according to the embodiment of the present invention, it is possible to reduce the warpage of the heat dissipation substrate 100 and to suppress a decrease in heat dissipation. In addition, it is preferable to make the space | interval of adjacent 1st through-hole 2a and the space | interval of adjacent 2nd through-hole 3a the same. Moreover, it is preferable to arrange | position the 2nd through-hole 3a in the center of the 1st through-hole 2a adjacent in planar view. Due to the heat applied to the heat dissipation substrate 100, deformation due to stress generated around the first through hole 2a and the second through hole 3a can be prevented from locally increasing.

  The heat dissipation substrate 100 is used, for example, as the semiconductor package 200 in a state where the surface of the fifth metal layer 5 opposite to the surface bonded to the third metal layer 3 is in contact with an external substrate (not shown). Therefore, when the heat dissipation substrate 100 is warped or deformed, the contact area between the heat dissipation substrate 100 and the external substrate is reduced, and the heat dissipation performance of the semiconductor package 200 via the heat dissipation substrate 100 is reduced. According to the heat dissipation substrate 100 according to the embodiment of the present invention, it is possible to reduce warping and deformation of the heat dissipation substrate 100 and to suppress a decrease in heat dissipation.

  In the heat dissipation substrate 100, the second metal layer 2 and the third metal layer 3 have Young's moduli larger than the Young's moduli of the first metal layer 1, the fourth metal layer 4, and the fifth metal layer 5. The second metal layer 2 is sandwiched between the first metal layer 1 and the fourth metal layer 4, and the third metal layer 3 is sandwiched between the first metal layer 1 and the fifth metal layer 5. Have a configuration. According to such a configuration, it is possible to effectively suppress a reduction in rigidity of the heat dissipation board 100 and improve the flatness of the surface of the heat dissipation board 100.

  Further, the second metal layer 2 and the third metal layer 3 having a small coefficient of thermal expansion are provided between the first metal layer 1 and the fourth metal layer 4 and between the first metal layer 1 and the fifth metal layer 5, respectively. Since the first metal layer 1, the fourth metal layer 4, and the fifth metal layer 5 are held by the second metal layer 2 and the third metal layer 3, thermal expansion is suppressed. This facilitates mounting of the semiconductor element 9 having a small thermal expansion coefficient.

  The plurality of first through holes 2a and the plurality of second through holes 3a are preferably arranged in a rectangular lattice shape or an oblique lattice shape in plan view. An example in which the first through-holes 2a and the second through-holes 3a are arranged in an oblique lattice is shown in FIGS. According to such a configuration, the heat dissipation path via the second metal layer 2 is provided dispersed in the second metal layer 2, and the heat dissipation path via the third metal layer 3 is provided dispersedly in the third metal layer 3. Therefore, the deviation of the heat distribution in the heat dissipation substrate 100 can be reduced, and thereby the warpage of the heat dissipation substrate 100 can be effectively suppressed.

  When the first through-holes 2a and the second through-holes 3a are arranged in an orthorhombic lattice shape, it is possible to prevent warping or bending of the heat dissipation substrate 100 in the long side direction or the short side direction.

  The plurality of first through holes 2a and the plurality of second through holes 3a may be disposed so as not to overlap each other in plan view. That is, the plurality of first through holes 2a and the plurality of second through holes 3a may be disposed so as not to overlap with each other in plan view. According to such a configuration, warpage of the heat dissipation substrate 100 can be further effectively reduced.

  Each of the plurality of first through holes 2a may be disposed so as to overlap at least one of the plurality of second through holes 3a when viewed in plan. That is, each of the plurality of first through holes 2a may be disposed so that a part thereof overlaps at least one of the plurality of second through holes 3a. According to such a configuration, it is possible to reduce the uneven distribution of heat in the heat dissipation substrate 100 and to efficiently conduct heat in the thickness direction of the heat dissipation substrate 100 via the metal member 6.

  In plan view, the areas of the plurality of first through holes 2a are equal to each other, the areas of the plurality of second through holes 3a are equal to each other, and the area of the second through holes 3a is larger than the area of the first through holes 2a. May be large. Thereby, the thermal conductivity from the fourth metal layer 4 to the fifth metal layer 5 of the heat dissipation substrate 100 can be improved.

  The heat dissipation substrate 100 according to the embodiment of the present invention is manufactured as follows.

  First, the first metal layer 1, the fourth metal layer 4, and the fifth metal layer 5 made of copper or an alloy containing copper are prepared by punching or cutting using a mold, and the mold is formed. By performing the punching process or the cutting process used, the second metal layer 2 in which a plurality of first through holes 2a made of molybdenum or an alloy containing molybdenum are formed, and the second metal layer 2 in which a plurality of second through holes 3a are formed. Three metal layers 3 are prepared.

  Then, after laminating the first metal layer 1, the second metal layer 2, the third metal layer 3, the fourth metal layer 4, and the fifth metal layer 5 in a predetermined order, by performing a rolling pressure bonding treatment, The heat dissipation substrate 100 in which the metal members 6 constituting the first metal layer 1, the fourth metal layer 4, and the fifth metal layer 5 are filled in the first through hole 2a and the second through hole 3a is obtained.

  The heat dissipation substrate 100 according to the embodiment of the present invention may be manufactured as follows. First, as described above, the first metal layer 1, the fourth metal layer 4, and the fifth metal layer 5 are prepared. Furthermore, the second metal layer 2 in which the first through hole 2a is pre-filled with the metal member 6 and the third metal layer 3 in which the second through hole 3a is pre-filled with the metal member 6 are prepared. Next, between the first metal layer 1 and the second metal layer 2, between the first metal layer 1 and the third metal layer 3, between the second metal layer 2 and the fourth metal layer 4, and third A preform made of a brazing material such as silver-copper brazing is sandwiched between the metal layer 3 and the fifth metal layer 5. In this state, the heat dissipation substrate 100 is put into a high-temperature furnace (for example, about 800 ° C. when silver-copper brazing is used), the preform of the brazing material is melted, and then taken out from the high-temperature furnace and cooled. can get.

  The semiconductor package 200 according to the embodiment of the present invention includes the heat dissipation substrate 100 having the above-described configuration, a frame 7 made of an insulator, and a power supply terminal 8, and the fourth metal layer 4 of the heat dissipation substrate 100. Further, the frame body 7 made of an insulator is attached, and the power supply terminal 8 is attached to the frame body 7.

The frame body 7 only needs to have insulating properties. For example, the frame body 7 may be made of resin or ceramics. In the semiconductor package 200 according to an embodiment of the present invention, the frame body 7, for example, made of _Al 2 _{O 3} quality ceramic, AlN _ceramics, 3Al ₂ O 3 · 2SiO insulator such ₂ quality ceramics.

  According to the semiconductor package 200, by including the heat dissipation substrate 100, it is possible to suppress a decrease in heat dissipation to the external heat dissipation body due to warpage or deformation of the heat dissipation substrate 100. Moreover, since there is little curvature of the thermal radiation board | substrate 100, possibility that the frame 7 attached to the thermal radiation board | substrate 100 will peel or a crack will arise by bending stress can be reduced. The semiconductor package 200 is particularly suitable for use in mounting a semiconductor element 9 for high power use and other highly heat-generating electronic components.

The semiconductor device 300 according to the embodiment of the present invention includes the semiconductor package 200 having the above configuration and the semiconductor element 9. The semiconductor element 9 is mounted on the semiconductor package 200, and the power supply terminal 8 and the semiconductor element 9 are mounted. Are electrically connected by a bonding wire 10. The semiconductor element 9 is mounted on a region inside the frame body 7 of the fourth metal layer 4.
Thereafter, the semiconductor element 9 is sealed with potting resin, or a lid is attached to the upper surface of the frame body 7 to seal the semiconductor element 9, thereby protecting the semiconductor device 300.

  According to the semiconductor device 300, by including the semiconductor package 200, it is possible to suppress warping and deformation of the heat dissipation substrate 100, to dissipate heat generated from the semiconductor element 9 well, and to have excellent sealing performance. A semiconductor device with improved reliability can be provided.

DESCRIPTION OF SYMBOLS 1 1st metal layer 1a 1st surface 1b 2nd surface 2 2nd metal layer 2a 1st through-hole 3 3rd metal layer 3a 2nd through-hole 4 4th metal layer 5 5th metal layer 6 Metal member 7 Frame 8 Terminal for power supply 9 Semiconductor element 10 Bonding wire 100 Heat dissipation substrate 200 Semiconductor package 300 Semiconductor device

Claims (10)

A first metal layer;
A second metal layer bonded to the first surface of the first metal layer, the second metal layer provided with a plurality of first through holes penetrating in the thickness direction;
A third metal layer bonded to a second surface of the first metal layer opposite to the first surface, the third metal layer having a plurality of second through holes penetrating in the thickness direction; ,
A fourth metal layer bonded to a surface of the second metal layer opposite to a surface bonded to the first surface of the first metal layer;
A fifth metal layer bonded to a surface of the third metal layer opposite to a surface bonded to the second surface of the first metal layer;
A metal member filled in the plurality of first through holes and the plurality of second through holes,
The first metal layer, the fourth metal layer, and the fifth metal layer have Young's moduli smaller than Young's moduli of the second metal layer and the third metal layer,
A radiating board, wherein a centroid of each of the plurality of first through holes and a centroid of each of the plurality of second through holes are misaligned in plan view.   The first metal layer, the fourth metal layer, the fifth metal layer, and the metal member are made of copper or an alloy containing copper, and the second metal layer and the third metal layer are molybdenum or molybdenum. The heat-radiating substrate according to claim 1, comprising an alloy containing   The said 1st metal layer, the said 4th metal layer, and the said 5th metal layer have thickness larger than the thickness of the said 2nd metal layer and the said 3rd metal layer, The said 1 or 2 characterized by the above-mentioned. The heat dissipation board of description.   4. The structure according to claim 1, wherein the plurality of first through holes and the plurality of second through holes are arranged in a rectangular lattice shape or an oblique lattice shape in a plan view. The heat dissipation board as described in the item.   5. The heat dissipation substrate according to claim 1, wherein the plurality of first through holes and the plurality of second through holes do not overlap in a plan view.   5. The device according to claim 1, wherein each of the plurality of first through holes overlaps with at least one of the plurality of second through holes in a plan view. The heat dissipation board described.   In plan view, the areas of the plurality of first through holes are equal to each other, the areas of the plurality of second through holes are equal to each other, and the areas of the plurality of second through holes are equal to those of the plurality of first through holes. It is larger than an area, The heat dissipation board | substrate of any one of Claims 1-6 characterized by the above-mentioned.   8. The planar view, wherein each of the plurality of first through holes and the plurality of second through holes has an elliptical shape or an oval shape. The heat dissipation board of description. The heat dissipation board according to any one of claims 1 to 8,
A frame made of an insulator fixed to the fourth metal layer of the heat dissipation substrate;
A power supply terminal attached to the frame;
Including semiconductor package. A semiconductor package according to claim 9;
A semiconductor element mounted on the semiconductor package;
A semiconductor device including:

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