heat sink

Abstract

To provide a heat sink whose passage is electrically insulated, and which has ensured conduction between an upper surface and a lower surface.SOLUTION: A heat sink 2 comprises: a passage member 4 inside of which a passage is formed; an upper insulating plate 6 which electrically insulates an upper surface of the passage member 4; a lower insulating plate 8 which electrically insulates a lower surface of the passage member 4; an upper conductive plate 10 which is disposed on the upper insulating plate 6 and has a protruding part 10a protruding from an end of the upper insulating plate 6; a lower conductive plate 12 which is disposed under the lower insulating plate 8 and has a protruding part 12a protruding from an end of the lower insulating plate 8; and a conductive block 14 which is disposed between the protruding part 10a of the upper conductive plate 10 and the protruding part 12a of the lower conductive plate 12 so as to electrically connect the upper conductive plate 10 to the lower conductive plate 12.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a heat sink for cooling a semiconductor device. [Background technology]

[0002] Water-cooled heat sinks are used as heat sinks for cooling semiconductor elements such as laser diodes. Water-cooled heat sinks include a heat dissipation member on which the semiconductor element is mounted, and flow paths called microchannels are formed inside the heat dissipation member. In water-cooled heat sinks, cooling water flows through the flow paths to cool the heated semiconductor element (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-186527 Summary of the Invention [Problem to be solved by the invention]

[0004] In heat sinks for cooling semiconductor devices, multiple heat sinks may be stacked. In this case, the upper and lower ends of the stack of multiple heat sinks serve as electrodes, so electrical continuity is required between the upper and lower surfaces of each heat sink. On the other hand, in heat sinks, if water flowing through the channels reacts with electricity, it will accelerate the corrosion of the components that form the channels, so the channels must be electrically insulated.

[0005] An object of the present invention is to provide a heat sink in which the flow paths are electrically insulated and electrical continuity between the upper surface and the lower surface is ensured. [Means for solving the problem]

[0006] According to the present invention, there is provided the following heat sink that solves the above problems: "A heat sink for cooling a semiconductor element, a flow path member having a flow path formed therein; an upper insulating plate that electrically insulates an upper surface of the flow path member; a lower insulating plate that electrically insulates the lower surface of the flow path member; an upper conductive plate disposed above the upper insulating plate and having a protrusion protruding from an end of the upper insulating plate; a lower conductive plate disposed below the lower insulating plate and having a protrusion protruding from an end of the lower insulating plate; a conductive block disposed between the protruding portion of the upper conductive plate and the protruding portion of the lower conductive plate, electrically connecting the upper conductive plate and the lower conductive plate.

[0007] Preferably, the conductive block has a notch extending in the vertical direction. It is desirable to provide a gap between the flow path member and the conductive block. It is preferable that the region where the semiconductor element is mounted is provided at one end, and the conductive block is provided at the other end. [Effects of the Invention]

[0008] In the heat sink of the present invention, the flow path is electrically insulated by the upper insulating plate and the lower insulating plate, and a conductive block is arranged between the protrusion of the upper conductive plate and the protrusion of the lower conductive plate, thereby ensuring conductivity between the upper and lower surfaces. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of a heat sink constructed in accordance with the present invention; [Figure 2] 2 is a perspective view showing the heat sink shown in FIG. 1 with an upper conductive plate and an upper insulating plate removed. [Figure 3] FIG. 2 is an exploded perspective view of the heat sink shown in FIG. 1. [Figure 4] Partial cross-section of the heat sink shown in Figure 1 DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a heat sink configured according to the present invention will be described with reference to the drawings.

[0011] (heat sink 2) As shown in FIG. 1, the water-cooled heat sink 2 is made of a material with good heat dissipation properties. The heat sink 2 has an overall rectangular parallelepiped shape, and a semiconductor element (object to be cooled) such as a laser diode is mounted in a predetermined region on the top surface of the heat sink 2 (the region indicated by the symbol R in FIG. 1 in the illustrated embodiment). As can be seen from FIG. 1, region R is provided at one end of the heat sink 2 in the longitudinal direction (X direction). The X direction is the direction indicated by the arrow X in FIG. 1. The Y direction is perpendicular to the X direction, and the Z direction is the up-down direction perpendicular to the X and Y directions.

[0012] The heat sink 2 has supply holes 2a for supplying cooling water to the flow paths of the heat sink 2, discharge holes 2b for discharging cooling water from the flow paths of the heat sink 2, and fastening holes 2c for passing screws (not shown) through them in the vertical direction (Z direction). Note that the multiple heat sinks 2 stacked in the vertical direction are fastened to each other by the screws passing through the fastening holes 2c.

[0013] Referring to Figures 2 to 4, the heat sink 2 comprises a flow path member 4, an upper insulating plate 6, a lower insulating plate 8, an upper conductive plate 10, a lower conductive plate 12, and a conductive block 14.

[0014] (Flow path member 4) The flow path member 4 can be formed from a material with good heat dissipation properties, and copper is preferable because it is easy to process and relatively low cost. In the illustrated embodiment, as shown in Figures 3 and 4, the flow path member 4 is a laminate in which six rectangular copper flow path plates 4a, 4b, 4c, 4d, 4e, and 4f are stacked in the vertical direction and joined together. The sizes (dimensions in the X and Y directions) of each of the flow path plates 4a to 4f may be the same.

[0015] Each of the flow path plates 4a to 4f is etched before being joined together to form a plurality of openings (reference numerals omitted) that form the supply holes 2a, the discharge holes 2b, and the fastening holes 2c. When the flow path plates 4a to 4f are joined together, the openings of each of the flow path plates 4a to 4f form a flow path connecting the supply holes 2a and the discharge holes 2b. The shape of the flow path of the flow path member 4 and the number of flow path plates can be set as desired.

[0016] (Upper insulating plate 6, lower insulating plate 8) The upper insulating plate 6 and the lower insulating plate 8 may be formed, for example, from a known DCB substrate. The DCB substrate is a laminated substrate in which metal conductive layers are directly bonded to the upper and lower surfaces of an insulating layer by the Direct Copper Bond method.

[0017] 4, the upper insulating plate 6 has a rectangular insulating layer 6a and rectangular conductive layers 6b, 6c directly bonded to the upper and lower surfaces of the insulating layer 6a. Similar to the upper insulating plate 6, the lower insulating plate 8 also has a rectangular insulating layer 8a and rectangular conductive layers 8b, 8c directly bonded to the upper and lower surfaces of the insulating layer 8a.

[0018] The insulating layers 6a and 8a may be made of a material having electrical insulation and high heat dissipation properties, such as aluminum nitride, silicon carbide, aluminum oxide, diamond, sapphire, etc. The conductive layers 6b, 6c, 8b, and 8c may be made of copper.

[0019] The upper insulating plate 6 is disposed on the upper surface of the flow path member 4, and the lower surface of the conductive layer 6c is bonded to the upper surface of the uppermost flow path plate 4a. The lower insulating plate 8 is disposed on the lower surface of the flow path member 4, and the upper surface of the conductive layer 8b is bonded to the lower surface of the lowermost flow path plate 4f. The upper insulating plate 6 electrically insulates the upper surface of the flow path member 4, and the lower insulating plate 8 electrically insulates the lower surface of the flow path member 4.

[0020] In the illustrated embodiment, the sizes (dimensions in the X and Y directions) of the upper and lower insulating plates 6, 8 are the same as the size of the flow path member 4, but they do not have to be the same as the size of the flow path member 4 as long as the upper and lower surfaces of the flow path member 4 can be electrically insulated.

[0021] As shown in FIG. 3, the upper and lower insulating plates 6, 8 are formed with circular openings (reference numerals omitted) that constitute the supply hole 2a, the discharge hole 2b and the fastening hole 2c.

[0022] (Upper conductive plate 10, lower conductive plate 12) The upper and lower conductive plates 10, 12 are each rectangular and may be made of a metal material with good heat dissipation and conductivity, such as copper. As shown in Fig. 4, the upper conductive plate 10 is disposed above the upper insulating plate 6 and is bonded to the upper conductive layer 6b of the upper insulating plate 6. The X-direction dimension of the upper conductive plate 10 is larger than the X-direction dimension of the upper insulating plate 6, and the upper conductive plate 10 has a protrusion 10a that protrudes in the X-direction from the X-direction end of the upper insulating plate 6.

[0023] The lower conductive plate 12 is disposed below the lower insulating plate 8 and is bonded to the conductive layer 8c at the bottom of the lower insulating plate 8. The X-direction dimension of the lower conductive plate 12 is larger than the X-direction dimension of the lower insulating plate 8, and the lower conductive plate 12 has a protrusion 12a that protrudes in the X-direction from the X-direction end of the lower insulating plate 8.

[0024] The Y-direction dimensions of the upper and lower conductive plates 10, 12 may be the same as the Y-direction dimensions of the flow path member 4 and the upper and lower insulating plates 6, 8. Similarly to the upper and lower insulating plates 6, 8, the upper and lower conductive plates 10, 12 also have circular openings (reference numerals omitted) that form the supply holes 2a, discharge holes 2b, and fastening holes 2c.

[0025] (Conductive Block 14) The conductive block 14 has a rectangular parallelepiped shape and can be formed from a metal material with good heat dissipation and conductivity, such as copper. As shown in FIG. 4, the conductive block 14 is disposed between the protrusion 10a of the upper conductive plate 10 and the protrusion 12a of the lower conductive plate 12. The conductive block 14 is preferably disposed away from the region R where the semiconductor element (object to be cooled) is mounted. In the illustrated embodiment, as shown in FIG. 1, the region R is provided at one end of the heat sink 2 in the longitudinal direction (X direction), and the conductive block 14 is provided at the other end of the heat sink 2 in the longitudinal direction (X direction). A plurality of conductive blocks 14 may be provided.

[0026] The Z-direction dimension (vertical dimension) of the conductive block 14 corresponds to the distance between the protrusion 10a of the upper conductive plate 10 and the protrusion 12a of the lower conductive plate 12. The upper surface of the conductive block 14 is joined to the lower surface of the protrusion 10a, and the lower surface of the conductive block 14 is joined to the upper surface of the protrusion 12a. Therefore, the upper conductive plate 10 and the lower conductive plate 12 are electrically connected by the conductive block 14, and conductivity between the upper and lower surfaces of the heat sink 2 (conduction between the upper surface of the upper conductive plate 10 and the lower surface of the lower conductive plate 12) is ensured.

[0027] Continuing the explanation with reference to Fig. 4, it is preferable that the X-direction dimension of the conductive block 14 is smaller than the X-direction dimension of the protrusions 10a and 12a, and that a gap G is provided between the conductive block 14 and the flow path member 4. This is because it is possible to cut off electrical continuity between the conductive block 14 and the flow path member 4 without interposing an insulating member (not shown) between the conductive block 14 and the flow path member 4.

[0028] In addition, in the illustrated embodiment, a gap G is provided between the conductive block 14 and each of the upper and lower insulating plates 6 and 8, so that the conductive block 14 and the flow path member 4 are not electrically connected via the conductive layer 6c at the bottom of the upper insulating plate 6 or the conductive layer 8b at the top of the lower insulating plate 8.

[0029] The Y-direction dimension of the conductive block 14 may be the same as the Y-direction dimension of the upper and lower conductive plates 10 and 12 .

[0030] 2 and 3, it is preferable that a notch 14a extending in the vertical direction is formed in the conductive block 14. When the notch 14a is formed, thermal distortion occurring when joining the flow path member 4, the upper and lower insulating plates 6 and 8, the upper and lower conductive plates 10 and 12, and the conductive block 14 is absorbed, thereby preventing poor joining of the above members.

[0031] In the illustrated embodiment, the notch 14a is formed on the side surface facing the flow path member 4, but this is not limitative and the notch 14a may be formed on any side surface as long as the notch 14a extends in the vertical direction. In addition, one or more notches 14a may be formed.

[0032] (Method of manufacturing heat sink 2) When manufacturing the heat sink 2, first, the above-mentioned plates (flow path plates 4a to 4f, upper and lower insulating plates 6, 8, upper and lower conductive plates 10, 12) are prepared with the required openings formed therein by etching or the like, and then a conductive block 14 is prepared with a cutout 14a formed therein.

[0033] Next, an oxide film is formed on the surface of each of the plates. A known method can be used to form the oxide film. Note that it is not necessary to form an oxide film on the surfaces of the upper and lower insulating plates 6 and 8.

[0034] Next, as shown in Figures 3 and 4, the above plates are stacked in a predetermined order, and a conductive block 14 is placed between the protrusion 10a of the upper conductive plate 10 and the protrusion 12a of the lower conductive plate 12.

[0035] The stacked plates and conductive block 14 are then heated to a predetermined temperature (for example, 1085°C), which reduces and removes the oxide film, and bonds the stacked plates and conductive block 14 together. In this way, the heat sink 2 is formed.

[0036] As described above, the heating temperature when joining the stacked plates and conductive block 14 together is as high as 1085°C. Also, as described above, the stack of the plates (the stack of flow path plates 4a to 4f, upper and lower insulating plates 6, 8, and upper and lower conductive plates 10, 12) includes insulating layers 6a, 8a made of aluminum nitride or the like. On the other hand, the conductive block 14 is made of a metal material with good heat dissipation and conductivity, such as copper.

[0037] That is, the thermal expansion coefficient of the material of the insulating layers 6a and 8a is generally smaller than that of the material of the conductive block 14. Therefore, the thermal distortion occurring when the stack of plates is joined is suppressed by the insulating layers 6a and 8a and is smaller than the thermal distortion occurring when the conductive block 14 is joined. In this regard, in the illustrated embodiment, the notch 14a formed in the conductive block 14 absorbs the thermal distortion occurring when joining, thereby preventing poor joining due to the thermal distortion.

[0038] As described above, in the heat sink 2 of the illustrated embodiment, the flow paths are electrically insulated by the upper insulating plate 6 and the lower insulating plate 8, and the conductive block 14 is disposed between the protrusion 10a of the upper conductive plate 10 and the protrusion 12a of the lower conductive plate 12, thereby ensuring electrical continuity between the upper and lower surfaces. [Explanation of symbols]

[0039] 2: Heat sink 4: Flow path material 6: Upper insulating plate 8: Lower insulating plate 10: Upper conductive plate 10a:Protrusion 12: Lower conductive plate 12a:Protrusion 14: Conductive block 14a: Notch

Claims

1. A heat sink for cooling a semiconductor device, a flow path member having a flow path formed therein; an upper insulating plate that electrically insulates an upper surface of the flow path member; a lower insulating plate that electrically insulates the lower surface of the flow path member; an upper conductive plate disposed above the upper insulating plate and having a protrusion protruding from an end of the upper insulating plate; a lower conductive plate disposed below the lower insulating plate and having a protrusion protruding from an end of the lower insulating plate; a conductive block disposed between the protrusion of the upper conductive plate and the protrusion of the lower conductive plate, electrically connecting the upper conductive plate and the lower conductive plate.

2. The heat sink according to claim 1 , wherein the conductive block has a notch extending in a vertical direction.

3. The heat sink according to claim 1 , wherein a gap is provided between the flow path member and the conductive block.

4. 2. The heat sink according to claim 1, wherein the region where the semiconductor element is mounted is provided at one end, and the conductive block is provided at the other end.

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