Ceramic Substrate Structure, Intelligent Power Module and Preparation Method Thereof

Abstract

The present invention relates to a ceramic substrate structure, an intelligent power module and a preparation method thereof, which are used to solve the technical problem of glue overflow during the plastic encapsulation of the ceramic substrate. The ceramic substrate structure of the present invention includes a ceramic substrate; and a fixing part which is arranged on the ceramic substrate and is used to fix the insertion part of the lead frame. By arranging a fixing part for fixing the insertion part of the pin frame inside the ceramic substrate, the connection part between the ceramic substrate and the pin frame is located inside the ceramic substrate, so as to ensure that the ceramic substrate and the pin frame are parallel, which can avoid the inclination of the ceramic substrate caused by uneven solder paste thickness, resulting in glue overflow during plastic encapsulation, and avoid the phenomenon of warping or even cracking caused by the too tight fitting between the ceramic substrate and the pin frame.

Description

Technical Field

[0001] The present invention relates to the field of electronic components, and particularly to a ceramic substrate structure, an intelligent power module and a preparation method thereof. Background Art

[0002] The double-sided copper-clad ceramic substrate (DBC) has good thermal conductivity, and at the same time, the copper layer on the front side of the ceramic can be etched for making circuits, so it is currently widely used in the field of power semiconductor packaging. In the semiconductor injection molding process, the copper layer on the reverse side needs to be exposed on the epoxy resin surface for heat dissipation. In the injection molding process, it is required that the DBC can be completely fitted with the lower mold after the mold is closed. If the fitting is not tight, it will cause the resin to overflow onto the DBC surface, affecting the heat dissipation performance of the module. If the fitting is too tight, it will cause the ceramic to crack and damage the module; since the DBC has undergone high-temperature welding before injection molding, there will also be a problem of substrate warping at the edge position, which also cannot make the DBC fit tightly with the mold. Summary of the Invention

[0003] The present invention provides a ceramic substrate structure, an intelligent power module and a preparation method thereof, which are used to solve the technical problem of glue overflow during the plastic encapsulation of the ceramic substrate.

[0004] According to the first aspect of the present invention, the present invention provides a ceramic substrate structure, including:

[0005] A ceramic substrate; and

[0006] A fixing part, which is arranged inside the ceramic substrate and is used to fix the insertion part of the lead frame.

[0007] Optionally, the fixing part includes a groove, and the insertion part of the lead frame is inserted into the groove and fixed to the groove.

[0008] Optionally, the ceramic substrate includes:

[0009] A ceramic layer;

[0010] A first copper-clad layer, which is arranged on the first surface of the ceramic layer and is used to make circuits; and

[0011] A second copper-clad layer, which is arranged on the second surface of the ceramic layer opposite to the first surface and is used for heat dissipation and for cooperating with the lead frame for encapsulation.

[0012] Optionally, the groove is arranged on one side of the first copper-clad layer and extends to the other side.

[0013] Optionally, the structure of the groove is the same as the shape of the insertion part.

[0014] Optionally, the number of the grooves is one or more, and the insertion parts are arranged in one-to-one correspondence with the grooves.

[0015] Optionally, a welding material is arranged at the joint of the groove and the insertion part.

[0016] According to the second aspect of the present invention, the present invention provides an intelligent power module, further comprising a chip arranged on the ceramic substrate, and the chip is electrically connected to the lead frame.

[0017] Optionally, the intelligent power module further comprises a plastic package shell arranged outside the ceramic substrate.

[0018] According to the third aspect of the present invention, the present invention provides a method for manufacturing an intelligent power module, which is characterized by comprising the following steps:

[0019] A fixing part matching the insertion part is arranged in the ceramic substrate;

[0020] After the insertion part is arranged in the fixing part, a welding material is arranged at the joint of the fixing part and the insertion part and the two are fixed;

[0021] The chip is fixed on the ceramic substrate, and the upper end of the chip is electrically connected to the lead frame;

[0022] A plastic package shell is arranged outside the ceramic substrate.

[0023] Compared with the prior art, the advantages of the present invention are as follows: By arranging a fixing part for fixing the lead frame insertion part inside the ceramic substrate, the connection part between the ceramic substrate and the lead frame is located inside the ceramic substrate, so as to ensure that the ceramic substrate and the lead frame are parallel, and it can avoid the phenomenon that the ceramic substrate tilts due to uneven solder paste thickness, resulting in glue overflow during plastic packaging, and avoid the phenomenon of warping or even cracking caused by the too tight fit between the ceramic substrate and the lead frame. Description of the Drawings

[0024] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the drawings.

[0025] Figure 1 is a schematic structural diagram of the ceramic substrate in the embodiment of the present invention;

[0026] Figure 2a and Figure 2b is a schematic structural diagram of the lead frame in the embodiment of the present invention;

[0027] Figure 3 is a schematic structural diagram of the insertion part inserted into the fixing part in the embodiment of the present invention;

[0028] Figure 4 is a front view of a ceramic substrate in an embodiment of the present invention;

[0029] Figure 5 is a schematic structural view of a ceramic substrate in the prior art.

[0030] Reference numerals: 1 - ceramic substrate, 2 - groove, 3 - lead frame, 4 - insertion part, 5 - first copper-clad layer, 6 - second copper-clad layer, 1-1 ceramic substrate. Detailed implementation manners

[0031] The present invention will be further described below with reference to the accompanying drawings.

[0032] As Figure 5 shown, in the prior art, the ceramic substrate 1-1 is attached to the pins of the lead frame through the first copper-clad layer, solder paste is applied to the joint between the second copper-clad layer and the lead frame, and then encapsulation is performed; however, since the first copper-clad layer and the pins are not fixed, it may cause the ceramic substrate 1-1 and the lead frame to move or tilt relative to each other, resulting in uneven solder paste thickness during solder paste application and overflow of glue during encapsulation.

[0033] As Figure 1 and Figure 3 shown, the present invention provides a ceramic substrate structure, which includes: a ceramic substrate 1 and a fixing part provided on the ceramic substrate 1. The insertion part 4 of the lead frame 3 can be inserted and fixed through the fixing part on the ceramic substrate 1, and the ceramic substrate 1 and the lead frame 3 are kept parallel, thus avoiding uneven solder paste thickness that may be caused when applying solder paste at the joint between the insertion part 4 and the fixing part, and further avoiding the phenomenon of glue overflow during encapsulation due to tilting of the ceramic substrate 1.

[0034] As Figure 1 and Figure 2a and Figure 2b shown, preferably, the fixing part includes a groove 2. The groove 2 can fix the insertion part 4 of the lead frame 3. Designing the fixing part as a groove 2 is convenient for preparation. The insertion part 4 of the lead frame 3 is a pin, and the pin is inserted into the groove 2 to fix the lead frame 3.

[0035] In another embodiment, a groove 2 having the same height as the ceramic substrate 1 is provided on the lead frame 3, which can enable the ceramic substrate 1 to be inserted into and fixed in the groove 2, and can also achieve the technical effect of uniform solder paste thickness during solder paste application and no glue overflow during encapsulation.

[0036] Optionally, as Figure 4 shown, the ceramic substrate 1 includes: a ceramic layer, a first copper-clad layer 5 and a second copper-clad layer 6.

[0037] Among them, the ceramic layer 1 is relatively light and non-conductive as a substrate.

[0038] The first copper-clad layer 5 is disposed on the first surface of the ceramic layer for fabricating a circuit;

[0039] The second copper-clad layer 6 is disposed on the second surface of the ceramic layer opposite to the first surface for heat dissipation and for cooperating with the lead frame 3 for encapsulation. A groove 2 is provided on the first copper-clad layer 5. By inserting the pins of the lead frame 3 into the groove 2, the lead frame 3 is fixed and parallel to the ceramic substrate 1, which ensures that the lead frame 3 is in contact with the second copper-clad layer 6 of the ceramic substrate 1. Furthermore, the thickness of the solder paste is uniform when the solder paste is applied to the second copper-clad layer 6 and the lead frame 3, and there will be no phenomenon of glue overflow during plastic encapsulation.

[0040] Optionally, the groove 2 is disposed on one side of the first copper-clad layer 5 and extends to the other side thereof.

[0041] Optionally, the groove 2 has the same shape as the insertion portion 4, that is, the size of the groove 2 matches the size of the insertion portion 4, ensuring that the insertion portion 4 can be inserted into the groove 2 and fixed.

[0042] Optionally, the number of the grooves 2 is one or more, and the insertion portions 4 are provided in one-to-one correspondence with the grooves 2.

[0043] Optionally, the groove 2 is disposed along the length direction of the first copper-clad layer 5. For example, the number of the grooves 2 is 4, and the 4 grooves 2 are disposed on the first copper-clad layer 5 to facilitate processing and production.

[0044] The present invention further provides an intelligent power module, which further includes a chip disposed on the ceramic substrate 1, and the chip is electrically connected to the lead frame 3.

[0045] The present invention provides a method for manufacturing the above-mentioned intelligent power module, including the following steps:

[0046] The first step is to form a fixing portion on the ceramic substrate 1 that matches the size of the insertion portion 4;

[0047] The second step is to apply a layer of solder paste at the joint of the fixing portion and the insertion portion 4 after inserting the insertion portion 4 into the fixing portion for fixing;

[0048] The third step is to fix the chip on the ceramic substrate 1, connect the upper end of the chip to the lead frame 3, and then plastic-encapsulate the structure of the ceramic substrate 1.

[0049] The fourth step is to attach a layer of tin to the insertion portion 4 for facilitating soldering;

[0050] The fifth step is to cut off the redundant part of the lead frame 3 and stamp it into shape using a mold.

[0051] Optionally, the material for plastic encapsulation is epoxy resin.

[0052] Although the present invention has been described with reference to the preferred embodiments, various modifications can be made thereto and components thereof can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any manner. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A ceramic substrate structure, characterized in that, Comprising: A ceramic substrate; And a fixing portion which is arranged inside the ceramic substrate and is used for fixing the insertion portion of the lead frame; The fixing portion includes a groove, and the insertion portion of the lead frame is inserted into the groove and fixed to the groove; The ceramic substrate includes: A ceramic layer; A first copper-clad layer which is arranged on the first surface of the ceramic layer and is used for fabricating a circuit; and a second copper-clad layer which is arranged on the second surface of the ceramic layer opposite to the first surface and is used for heat dissipation and cooperating with the lead frame for encapsulation; The groove is arranged on one side of the first copper-clad layer and extends to the other side thereof. When the insertion portion of the lead frame is fixed to the groove, the ceramic substrate is parallel to the lead frame, and the lead frame is attached to the second copper-clad layer of the ceramic substrate.

2. The ceramic substrate structure according to claim 1, wherein, The structure of the groove is the same as the shape of the insertion portion.

3. The ceramic substrate structure according to claim 1, wherein, The number of the grooves is one or more, and the insertion portions and the grooves are arranged in one-to-one correspondence.

4. The ceramic substrate structure according to claim 1, wherein, A welding material is arranged at the joint of the groove and the insertion portion.

5. An intelligent power module, comprising the ceramic substrate structure according to any one of claims 1-4, characterized in that, It further includes a chip arranged on the ceramic substrate, and the chip is electrically connected to the lead frame.

6. The intelligent power module according to claim 5, characterized in that, It further includes a plastic encapsulation housing arranged outside the ceramic substrate.

7. A method for preparing the intelligent power module as described in claim 5, characterized in that, Including the following steps: Arranging a fixing portion matching the insertion portion in the ceramic substrate; After arranging the insertion portion in the fixing portion, arranging a welding material at the joint of the fixing portion and the insertion portion and fixing the two; Fixing the chip on the ceramic substrate and electrically connecting the upper end of the chip to the lead frame; Arranging a plastic encapsulation housing outside the ceramic substrate.

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