Copper-clad ceramic substrate and power module

Abstract

The embodiment of the utility model relates to the technical field of copper-clad ceramic substrates, in particular to a copper-clad ceramic substrate and a power module. A copper-clad ceramic substrate comprises: a copper foil layer; the first ceramic substrate is connected with the bottom surface of the copper foil layer, and a first through groove penetrating through the edge side of the first ceramic substrate is formed in the bottom surface of the first ceramic substrate; the second ceramic substrate is connected with the bottom surface of the first ceramic substrate, a second through groove penetrating through the side of the second ceramic substrate is formed in the top surface of the second ceramic substrate, and the second through groove and the first through groove are in butt joint to form a cooling water channel. According to the copper-clad ceramic substrate disclosed by the embodiment of the invention, the copper foil layer, the first ceramic substrate and the second ceramic substrate are matched to form the copper-clad ceramic substrate, so that the heat dissipation effect of the copper-clad ceramic substrate can be improved, and the warping degree value of the copper-clad ceramic substrate cannot be influenced.

Description

Technical Field

[0001] The embodiments of the present specification relate to the technical field of copper-clad ceramic substrates, and specifically to a copper-clad ceramic substrate and a power module. Background Art

[0002] Copper-clad ceramic substrate is an electronic basic material made by sintering copper foil directly on the ceramic surface using DCB (Direct Copper Bond) technology. Copper-clad ceramic substrate has excellent thermal cycling, shape stability, good rigidity, high thermal conductivity, high reliability, and the copper-clad surface can be etched with various patterns. It can be used in semiconductor refrigerators, electronic heaters, high-power power semiconductor modules and many other industrial electronic fields.

[0003] like Figure 4 As shown, most existing copper-clad ceramic substrates include a ceramic substrate and a copper foil layer covering the top surface of the ceramic substrate and a copper foil layer covering the bottom surface of the ceramic substrate. The copper-clad ceramic substrate with this structure has a poor heat dissipation effect. In particular, for high-power modules with high heat dissipation requirements, the copper-clad ceramic substrate with this structure may not meet the heat dissipation requirements.

[0004] To this end, the prior art proposes to open a microchannel in the copper foil layer on the bottom surface to improve the heat dissipation effect of the copper-clad ceramic substrate. However, the copper-clad ceramic substrate with this structure will greatly increase the warpage value. Utility Model Content

[0005] In view of the shortcomings of the prior art, the embodiments of this specification propose a copper-clad ceramic substrate and a power module that can improve the heat dissipation effect without affecting the warpage value.

[0006] The embodiment of this specification also proposes a copper-clad ceramic substrate, comprising:

[0007] Copper foil layer;

[0008] A first ceramic substrate is connected to the bottom surface of the copper foil layer, and a first through groove penetrating the side of the first ceramic substrate is formed on the bottom surface of the first ceramic substrate;

[0009] The second ceramic substrate is connected to the bottom surface of the first ceramic substrate, and the top surface of the second ceramic substrate is provided with a second through groove penetrating the side of the second ceramic substrate, and the second through groove is connected with the first through groove to form a cooling water channel.

[0010] Preferably, a first solder layer is provided on the top surface of the first ceramic substrate.

[0011] Preferably, the first ceramic substrate is connected to the copper foil layer by vacuum brazing through the first solder layer.

[0012] Preferably, a second solder layer is provided on the top surface of the second ceramic substrate.

[0013] Preferably, the second ceramic substrate is connected to the first ceramic substrate by vacuum brazing via a second solder layer.

[0014] Preferably, the first through groove includes a plurality of first straight groove portions and a plurality of first bent groove portions, a first bent groove portion connects two adjacent first straight groove portions, and the first straight groove portion located at the first end in the length direction of the first through groove passes through the side of the first ceramic substrate to form a first notch A1, and the first straight groove portion located at the second end in the length direction of the first through groove passes through the side of the first ceramic substrate to form a first notch B1.

[0015] Preferably, the second through groove includes a plurality of second straight groove portions and a plurality of second curved groove portions, a second curved groove portion connects two adjacent second straight groove portions, and the second straight groove portion located at the first end of the second through groove in the length direction passes through the side of the second ceramic substrate to form a second slot A2, and the second straight groove portion located at the second end of the second through groove in the length direction passes through the side of the second ceramic substrate to form a second slot B2; the first slot A1 and the second slot A2 are connected to form a water inlet of the cooling water channel; the first slot B1 and the second slot B2 are connected to form a water outlet of the cooling water channel.

[0016] Preferably, the thickness of the first ceramic substrate is 0.5-1 mm.

[0017] Preferably, the thickness of the second ceramic substrate is 0.5-1 mm.

[0018] The embodiment of the present specification also provides a power module, including the copper-clad ceramic substrate and a chip connected to the top surface of the copper foil layer.

[0019] Beneficial Effects

[0020] The copper-clad ceramic substrate of the embodiment of the present specification is formed by the cooperation of the copper foil layer, the first ceramic substrate and the second ceramic substrate, which can not only improve the heat dissipation effect of the copper-clad ceramic substrate but also does not affect the warpage value of the copper-clad ceramic substrate.

[0021] Further or more detailed beneficial effects will be described in detail in conjunction with specific examples in the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the overall structure of the copper-clad ceramic substrate in the embodiment of this specification;

[0023] Figure 2 It is a schematic diagram of the partial structure of the copper-clad ceramic substrate in the embodiment of this specification;

[0024] Figure 3 This is a schematic diagram of the structure of the second ceramic substrate in the embodiment of this specification;

[0025] Figure 4 It is a structural schematic diagram of a copper-clad ceramic substrate in the prior art. DETAILED DESCRIPTION

[0026] The technical solution of the utility model is further explained below with reference to the accompanying drawings and through specific implementation methods.

[0027] Embodiment 1:

[0028] like Figure 1 , Figure 2 As shown, this embodiment provides a copper-clad ceramic substrate, including a copper foil layer 1, a first ceramic substrate 3 and a second ceramic substrate 4 arranged in sequence from top to bottom.

[0029] The first ceramic substrate 3 is connected to the bottom surface of the copper foil layer 1 , and a first through groove penetrating through the side of the first ceramic substrate 3 is formed on the bottom surface of the first ceramic substrate 3 .

[0030] The second ceramic substrate 4 is connected to the bottom surface of the first ceramic substrate 3 , and a second through groove penetrating the side of the second ceramic substrate 4 is formed on the top surface of the second ceramic substrate 4 , and the second through groove is connected with the first through groove to form a cooling water channel 5 .

[0031] In this embodiment, the bottom copper foil layer in the prior art is removed, and then a second ceramic substrate 4 is added.

[0032] First, in this embodiment, a first through groove is provided on the first ceramic substrate 3, and a second through groove is provided on the second ceramic substrate 4, and heat dissipation and cooling are performed through a cooling water channel 5 formed by the second through groove and the first through groove. The cooling water channel 5 of this embodiment flows not only through the second ceramic substrate 4, but also through the first ceramic substrate 3. Compared with directly setting the cooling water channel in the bottom copper foil layer, the heat dissipation effect of the copper-clad ceramic substrate will be slightly improved; compared with the copper-clad ceramic substrate without a cooling water channel, its heat dissipation effect will be effectively improved.

[0033] Secondly, the reason why the bottom copper foil layer is provided in the prior art is to prevent the copper-clad ceramic substrate from warping. The inventors of the present application have found that the second ceramic substrate 4 is provided below the first ceramic substrate 3 to also prevent the copper-clad ceramic substrate from warping. And when the thickness of the second ceramic substrate 4 is of an appropriate value, its anti-warping effect is better than that of the bottom copper foil layer. That is, when the bottom of the copper-clad ceramic substrate is a copper foil layer, and a cooling water channel is provided in the bottom copper foil layer, the copper-clad ceramic substrate has a more serious warping phenomenon. However, the present embodiment adopts the second ceramic substrate 4. Even if the second ceramic substrate 4 is provided with a second through groove, when the thickness of the second ceramic substrate 4 is appropriate, the copper-clad ceramic substrate formed by the cooperation of the second ceramic substrate 4 with the first ceramic substrate 3 and the copper foil layer 1 has a significantly reduced warping value.

[0034] In summary, the copper-clad ceramic substrate formed by the copper foil layer 1, the first ceramic substrate 3 and the second ceramic substrate 4 in this embodiment can not only improve the heat dissipation effect of the copper-clad ceramic substrate but also does not affect its warpage value.

[0035] Furthermore, a first solder layer 6 is provided on the top surface of the first ceramic substrate 3 , and the first ceramic substrate 3 is connected to the copper foil layer 1 by vacuum brazing through the first solder layer 6 .

[0036] In this embodiment, a second solder layer 7 is disposed on the top surface of the second ceramic substrate 4 , and the second ceramic substrate 4 is connected to the first ceramic substrate 3 by vacuum brazing via the second solder layer 7 .

[0037] After the second solder layer 7 is arranged on the top surface of the second ceramic substrate 4 (i.e. the side with the second through groove) (the second solder layer 7 only needs to be coated on the plane, and the second solder layer 7 does not need to be coated inside the second through groove), and the first solder layer 6 is arranged on the top surface of the first ceramic substrate 3 (i.e. the side without the first through groove), the first ceramic substrate 3 and the second ceramic substrate 4 are dried first.

[0038] After the first ceramic substrate 3 and the second ceramic substrate 4 are dried, the copper foil layer 1, the first ceramic substrate 3, and the second ceramic substrate 4 are stacked from top to bottom to form a component to be welded. Then the component to be welded is placed in a vacuum brazing furnace, the vacuum degree in the furnace is controlled between 0.0008-0.01Pa, and the temperature in the furnace is controlled between 750-950℃. At the beginning, the temperature in the furnace is relatively low. When the temperature in the furnace rises to between 750-950℃, the first solder layer 6 and the second solder layer 7 begin to melt. The melted first solder layer 6 and the second solder layer 7 fill the entire weld through capillary flow to achieve welding between the copper foil layer 1 and the first ceramic substrate 3 and the first ceramic substrate 3 and the second ceramic substrate 4.

[0039] Firstly, vacuum brazing can reduce the number of voids in the first solder layer 6 and the second solder layer 7, so that the heat transfer effect of the copper-clad ceramic substrate is better, and then the heat dissipation effect of the copper-clad ceramic substrate is better.

[0040] Secondly, vacuum brazing can make the connection between the first ceramic substrate 3 and the second ceramic substrate 4 more sealed, so that the cooling medium in the cooling water channel 5 will not leak, and thus the copper-clad ceramic substrate can be effectively used for a long time without being scrapped due to leakage of the cooling medium.

[0041] In summary, in this embodiment, the copper foil layer 1 and the first ceramic substrate 3 are connected by vacuum brazing through the first solder layer 6, and the first ceramic substrate 3 and the second ceramic substrate 4 are connected by vacuum brazing through the second solder layer 7, so that the weld between the copper foil layer 1 and the first ceramic substrate 3 and the weld between the first ceramic substrate 3 and the second ceramic substrate 4 have few voids and good sealing, thereby making the heat transfer effect of the copper-clad ceramic substrate good and there will be no leakage of cooling medium, and finally making the heat dissipation effect of the copper-clad ceramic substrate better and the service life long.

[0042] Furthermore, the first through groove on the first ceramic substrate 3 of the present embodiment includes a plurality of first straight groove portions and a plurality of first bent groove portions, a first bent groove portion connects two adjacent first straight groove portions, and the first straight groove portion located at the first end in the length direction of the first through groove passes through the side of the first ceramic substrate 3 to form a first notch A1, and the first straight groove portion located at the second end in the length direction of the first through groove passes through the side of the first ceramic substrate 3 to form a first notch B1.

[0043] like Figure 3 As shown, the second through groove of the second ceramic substrate 4 of this embodiment includes a plurality of second straight groove portions 41 and a plurality of second curved groove portions 42, a second curved groove portion 42 connects two adjacent second straight groove portions 41, and the second straight groove portion 41 located at the first end of the second through groove in the length direction penetrates the side of the second ceramic substrate 4 to form a second notch A2, and the second straight groove portion 41 located at the second end of the second through groove in the length direction penetrates the side of the second ceramic substrate 4 to form a second notch B2. The first notch A1 and the second notch A2 are connected to form the water inlet of the cooling water channel 5; the first notch B1 and the second notch B2 are connected to form the water outlet of the cooling water channel 5.

[0044] The specific shape of the first through groove in this embodiment is the same as the specific shape of the second through groove. The second ceramic substrate 4 in this embodiment is only provided with one second through groove, so that the entire copper-clad ceramic substrate has only one second notch A2 (i.e., only one water inlet in the end) and one second notch B2 (i.e., only one water outlet in the end), so that the copper-clad ceramic substrate only needs to be connected to one water supply inlet and one water supply outlet of the circulating water supply equipment, and the assembly is more convenient.

[0045] like Figure 3 As shown, the second through groove of this embodiment includes a plurality of second straight groove portions 41 arranged in parallel, for example, there may be 9 second straight groove portions 41 arranged in parallel, and adjacent second straight groove portions 41 are connected by second curved groove portions 42, and the second curved groove portions 42 are semicircular in top view. There are a large number of second straight groove portions 41 and they are evenly distributed on the second ceramic substrate 4, so that the cooling medium can flow through almost the entire second ceramic substrate 4, thereby making the heat dissipation effect of the second ceramic substrate 4 very good.

[0046] The cross-section of the second through groove in this embodiment (a cross-section perpendicular to the second straight groove portion 41 or a cross-section perpendicular to the second curved groove portion 42 ) is rectangular. The second through groove of this shape can be easily opened on the second ceramic substrate 4 .

[0047] In summary, the cooling water channel 5 of this embodiment is formed by docking the first through groove and the second through groove of the same shape, and the second through groove has only one second notch A2 and one second notch B2, so that the cooling water channel 5 finally formed has only one water inlet and one water outlet. This arrangement makes it easier to assemble the copper-clad ceramic substrate with the circulating water supply equipment. In addition, the second through groove of this embodiment is arranged by the second straight groove portion 41 and the second curved groove portion 42, so that the second through groove can be distributed over a large area and evenly on the second ceramic substrate 4, thereby making the cooling water channel 5 finally formed can be distributed over a large area and evenly on the entire copper-clad ceramic substrate, and finally making the copper-clad ceramic substrate able to dissipate heat efficiently. Furthermore, the cross-sections of the first through groove and the second through groove are both rectangular, making it easier to open the first through groove and the second through groove.

[0048] Furthermore, in this embodiment, the thickness of the first ceramic substrate 3 is 0.5-1 mm, and the thickness of the second ceramic substrate 4 is 0.5-1 mm.

[0049] Specifically, the thickness of the first ceramic substrate 3 may be 0.63 mm, the height of the first through slot may be 0.45 mm, and the width of the first through slot may be 0.63 mm. The thickness of the second ceramic substrate 4 may be 0.63 mm, the height of the second through slot may be 0.45 mm, and the width of the second through slot may be 0.63 mm.

[0050] Alternatively, the thickness of the first ceramic substrate 3 may be 1 mm, the height of the first through groove may be 0.7 mm, and the width of the first through groove may be 1 mm. The thickness of the second ceramic substrate 4 may be 1 mm, the height of the second through groove may be 0.7 mm, and the width of the second through groove may be 1 mm.

[0051] The thickness of conventional ceramic substrates generally has several specifications such as 0.32 mm, 0.36 mm, 0.63 mm, and 1 mm. In order to simplify the manufacture of the copper-clad ceramic substrate, the present embodiment can directly use a ceramic substrate of existing specifications, but in order to open the through groove and to ensure the warpage value, the thickness of the ceramic substrate must be guaranteed, so the present embodiment can directly use a ceramic substrate with a thickness of 0.63 mm or 1 mm, that is, the thickness of the first ceramic substrate 3 and the second ceramic substrate 4 can both be 0.63 mm, or the thickness of the first ceramic substrate 3 and the second ceramic substrate 4 can both be 1 mm.

[0052] In addition, the inventors of the present application found that when the height of the through groove is approximately 0.7 times the thickness of the ceramic substrate and when the width of the through groove is the same as the thickness of the ceramic substrate, the cooling water flow in the cooling water channel 5 can efficiently take away the heat from the copper-clad ceramic substrate and can effectively prevent the copper-clad ceramic substrate from warping.

[0053] Embodiment 2:

[0054] This embodiment provides a power module such as Figure 1 As shown, it includes the copper-clad ceramic substrate in Example 1 and also includes a chip 2 connected to the top surface of the copper foil layer 1.

[0055] The above embodiments are only for describing the preferred implementation of the utility model, and are not intended to limit the concept and scope of the utility model. Without departing from the design concept of the utility model, various modifications and improvements made by ordinary persons in the art to the technical solution of the utility model should fall within the protection scope of the utility model, and the technical contents of the utility model for protection have been fully recorded in the claims.

Claims

1. A copper-clad ceramic substrate, characterized in that: include: Copper foil layer (1); A first ceramic substrate (3) connected to the bottom surface of the copper foil layer (1), and the bottom surface of the first ceramic substrate (3) is provided with a first through groove penetrating the side of the first ceramic substrate (3); The second ceramic substrate (4) is connected to the bottom surface of the first ceramic substrate (3), and the top surface of the second ceramic substrate (4) is provided with a second through groove penetrating the side of the second ceramic substrate (4), the second through groove and the first through groove being connected to form a cooling water channel (5).

2. A copper-clad ceramic substrate according to claim 1, characterized in that: A first solder layer (6) is provided on the top surface of the first ceramic substrate (3).

3. A copper-clad ceramic substrate according to claim 2, characterized in that: The first ceramic substrate (3) is connected to the copper foil layer (1) by vacuum brazing via the first solder layer (6).

4. The copper-clad ceramic substrate according to claim 1, characterized in that: A second solder layer (7) is provided on the top surface of the second ceramic substrate (4).

5. The copper-clad ceramic substrate according to claim 4, characterized in that: The second ceramic substrate (4) is connected to the first ceramic substrate (3) by vacuum brazing via the second solder layer (7).

6. The copper-clad ceramic substrate according to claim 1, characterized in that: The first through groove comprises a plurality of first straight groove portions and a plurality of first curved groove portions, wherein one first curved groove portion connects two adjacent first straight groove portions, and the first straight groove portion located at the first end in the length direction of the first through groove penetrates the side of the first ceramic substrate (3) to form a first notch A1, and the first straight groove portion located at the second end in the length direction of the first through groove penetrates the side of the first ceramic substrate (3) to form a first notch B1.

7. The copper-clad ceramic substrate according to claim 6, characterized in that: The second through groove comprises a plurality of second straight groove portions (41) and a plurality of second curved groove portions (42); a second curved groove portion (42) connects two adjacent second straight groove portions (41); the second straight groove portion (41) located at the first end in the length direction of the second through groove penetrates the side of the second ceramic substrate (4) to form a second notch A2; the second straight groove portion (41) located at the second end in the length direction of the second through groove penetrates the side of the second ceramic substrate (4) to form a second notch B2; the first notch A1 and the second notch A2 are connected to form a water inlet of the cooling water channel (5); the first notch B1 and the second notch B2 are connected to form a water outlet of the cooling water channel (5).

8. The copper-clad ceramic substrate according to claim 1, characterized in that: The thickness of the first ceramic substrate (3) is 0.5-1 mm.

9. The copper-clad ceramic substrate according to claim 1, characterized in that: The thickness of the second ceramic substrate (4) is 0.5-1 mm.

10. A power module, characterized in that: The copper-clad ceramic substrate comprises the copper-clad ceramic substrate as claimed in any one of claims 1 to 9, and further comprises a chip (2) connected to the top surface of the copper foil layer (1).

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