Ceramic-substrate-free power module and manufacturing method thereof

Abstract

The invention discloses a ceramic-substrate-free power module, which relates to the technical field of power electronic devices and comprises a power terminal, a signal terminal, a first welding layer, a first electrical connection component, a second welding layer, a second electrical connection component, a chip, a third welding layer and an insulating integrated substrate, the edge of the first electrical connection part is provided with a bend with a certain radian; the insulating integrated substrate comprises a heat dissipation substrate, an insulating substrate and a metal electrical connection layer which are sequentially arranged from bottom to top. The invention further discloses a manufacturing method of the ceramic-substrate-free power module, the parasitic parameters of the power module can be reduced, the thermal resistance of the power module is reduced, and the overall performance is improved comprehensively.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronic devices, in particular to a ceramic-free substrate power module and a manufacturing method thereof. Background Art

[0002] In order to meet the needs of the rapid development of new industries such as photovoltaics and new energy vehicles, more stringent requirements are put forward for the high reliability, low thermal resistance, low parasitic parameters and high power density of key power electronic devices and power modules. In traditional power modules, the packaging process involves ceramic substrate welding process, metal wire bonding process, etc. Among them, the ceramic substrate consists of a three-layer structure, upper and lower metal layers and a middle ceramic layer. Due to the different thermal expansion coefficients of different materials, in actual use, long-term, high-frequency high and low temperature working conditions force stress to be generated in the material, and it continues to accumulate, eventually leading to failure phenomena such as cracks and delamination in the material, seriously affecting the long-term service reliability of the power module.

[0003] Traditional power modules usually include a three-layer ceramic substrate structure (metal / ceramic / metal), such as Figure 1 The ceramic substrate 10 in the embodiment of the present invention needs to be welded or sintered (such as Figure 1 The ceramic substrate is fixed on the heat dissipation substrate (such as the welding / sintering layer 11) in the Figure 1 The heat dissipation substrate 12) in the heat dissipation substrate, due to the mismatch of thermal expansion coefficients between different materials, leads to stress accumulation during long-term use, and eventually leads to failure phenomena such as cracks and delamination of the material;

[0004] Due to the mismatch of thermal expansion coefficients of ceramic substrates, a multi-ceramic substrate solution is usually used in power module design to improve overall long-term reliability. However, this solution limits the effective area of ​​chip layout, which is not conducive to improving the power density of the power module. The ceramic substrate contains a three-layer structure, especially the ceramic layer has a relatively low thermal conductivity, resulting in a large thermal resistance of the power module, which is not conducive to improving its power density. Traditional metal bonding wires (such as Figure 1 The electrical connection method of the metal bonding wire 13) in the power module will result in large parasitic parameters, which will damage the overall performance of the power module, especially the key electrical parameters. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a ceramic substrate-free power module and a manufacturing method thereof. The present invention can not only reduce the parasitic parameters of the power module, but also reduce the thermal resistance of the power module, increase the power density, and achieve an all-round improvement in the overall performance of the power module.

[0006] The present invention adopts the following technical solutions to solve the above technical problems

[0007] A ceramic-free substrate power module according to the present invention comprises a power terminal, a signal terminal, a first welding layer, a first electrical connection component, a second welding layer, a second electrical connection component, a chip, a third welding layer and an insulating integrated substrate; the edge of the first electrical connection component is bent with a certain arc; wherein,

[0008] The insulating integrated substrate includes a heat dissipation substrate, an insulating substrate, and a metal electrical connection layer which are sequentially arranged from bottom to top. The heat dissipation substrate, the insulating substrate, and the metal electrical connection layer are integrally formed by hot pressing, wherein:

[0009] The power terminal and the signal terminal are electrically connected to the metal electrical connection layer through the first welding layer respectively;

[0010] The first electrical connection component is connected to the chip and the metal electrical connection layer respectively through the second welding layer to form an internal power electrical circuit of the power module;

[0011] The chip is connected to the metal electrical connection layer through the second electrical connection component to form an internal control electrical circuit of the power module;

[0012] The chip is fixed on the metal electrical connection layer through a third welding layer.

[0013] As a further optimization solution for a ceramic-substrate-free power module described in the present invention, the first electrical connection component is a copper clip, the edge of the copper clip has a 45°-90° bend, and the thickness of the copper clip is 0.08mm-0.15mm.

[0014] As a further optimization scheme of a ceramic substrate-free power module described in the present invention, the copper clip includes a chip connection plane, a bending plane and a metal electrical connection layer connection plane, and the edge of the chip connection plane of the copper clip has a 45°-90° bend.

[0015] As a further optimization scheme of a ceramic-substrate-free power module described in the present invention, the insulating integrated substrate is an organic insulating film integrated substrate, the insulating substrate is an organic insulating film, and the thickness of the insulating substrate is 0.05 mm-0.2 mm.

[0016] As a further optimization scheme of a ceramic-free substrate power module described in the present invention, the first welding layer is a terminal welding layer, the second welding layer is a copper clip welding layer, the third welding layer is a chip welding layer, and the second electrical connection component is a metal bonding wire.

[0017] As a further optimization scheme of a ceramic-free substrate power module described in the present invention, a functional circuit pattern is provided on the metal electrical connection layer, and power terminals and signal terminals are used for electrical connection with the outside, and the shape of the power terminals is an X-shape.

[0018] As a further optimization solution for a ceramic-substrate-free power module described in the present invention, the surface of the heat dissipation substrate is also plated with an anti-oxidation layer.

[0019] As a further optimization solution for a ceramic-substrate-free power module described in the present invention, the chip is a power chip, and the power chip includes an IGBT, FRD or SiC MOSFET chip.

[0020] As a further optimization scheme of a ceramic-substrate-free power module described in the present invention, the material of the organic insulating film is a polymer epoxy resin, the material of the heat dissipation substrate is copper or aluminum, and the material of the metal electrical connection layer is copper.

[0021] A method for manufacturing a power module without a ceramic substrate, comprising:

[0022] An insulating integrated substrate is manufactured by a hot pressing integrated forming method, wherein the insulating integrated substrate comprises a heat dissipation substrate, an insulating substrate, and a metal electrical connection layer which are sequentially arranged from bottom to top;

[0023] Using a reflow soldering process, the power terminal and the signal terminal are electrically connected to the metal electrical connection layer through the first soldering layer;

[0024] The electrical connection component is connected to the chip and the metal electrical connection layer respectively through the second welding layer, and the edge of the electrical connection component is bent with a certain arc;

[0025] Connecting the chip to the metal electrical connection layer using metal bonding wires by ultrasonic bonding;

[0026] The chip is fixed to the metal electrical connection layer through the third welding layer.

[0027] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

[0028] The present invention uses an organic insulating film integrated substrate instead of a ceramic substrate. This structure can not only improve the overall reliability of the power module, but also reduce thermal resistance and increase power density. On this basis, a copper clip structure is used instead of traditional metal bonding wires for internal electrical connections in the power module, reducing the parasitic parameters of the power module to achieve all-round improvement of the overall performance of the power module. The edge of the first electrical connection component is bent with a certain arc to improve the stress on the chip during assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a traditional power module structure;

[0030] Figure 2 This is the power module structure proposed by the present invention;

[0031] Figure 3It is an exploded diagram of the power module structure proposed by the present invention;

[0032] Figure 4 This is an exploded view of an organic insulating film integrated substrate;

[0033] Figure 5 It is a copper clip structure;

[0034] Figure 6 It is a schematic diagram of the chip connection plane, the bending plane and the metal electrical connection layer connection plane of the second copper clip.

[0035] The reference numerals in the figure are explained as follows: 10-ceramic substrate (three-layer structure); 11-welding / sintering layer; 12-heat dissipation substrate; 13-metal bonding wire (electrical connection); 01-power terminal; 02-signal terminal; 09-organic insulating film integrated substrate; 100-first copper clip; 101-second copper clip; 03-terminal welding layer; 04-copper clip; 05-copper clip welding layer; 06-metal bonding wire (signal part); 07-chip; 08-chip welding layer; 102-heat dissipation substrate; 103-organic insulating film layer; 104-metal electrical connection layer; A is the chip connection plane, B is the bending plane, and C is the metal electrical connection layer connection plane. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings:

[0037] Figure 1 It is a traditional power module structure, traditional metal bonding wire (such as Figure 1 The electrical connection mode of the metal bonding wire 13) in the power module will lead to large parasitic parameters, which will damage the overall performance of the power module, especially the key electrical parameters. The present invention can not only reduce the parasitic parameters of the power module, but also reduce the thermal resistance of the power module, increase the power density, and achieve an all-round improvement in the overall performance of the power module.

[0038] Figure 2 The power module structure of the present invention is Figure 3 It is an exploded diagram of the power module structure proposed by the present invention; Figure 4 It is an exploded view of an organic insulating film integrated substrate. An embodiment of a ceramic-free substrate power module structure provided by the present invention includes: a power terminal 01, a signal terminal 02, a terminal welding layer 03, a copper clip 04, a copper clip welding layer 05, a metal bonding wire 06, a chip 07, a chip welding layer 08, and an organic insulating film integrated substrate 09. The edge of the copper clip has a 45°-90° bend to improve the stress on the chip during assembly.

[0039] The organic insulating film integrated substrate structure comprises three layers, namely a heat dissipation substrate 102 , an organic insulating film 103 , and a metal electrical connection layer 104 .

[0040] The method for preparing the organic insulating film integrated substrate structure is hot pressing integrated forming. In traditional power modules, the ceramic substrate needs to be fixed to the heat dissipation substrate by welding or sintering. The upper metal layer of the ceramic substrate is responsible for electrical connection, the ceramic layer is responsible for electrical insulation, the lower metal layer is responsible for welding or sintering with the heat dissipation substrate, and the heat dissipation substrate is responsible for transferring heat to the external environment. The aforementioned organic insulating film integrated substrate 09 has electrical connection function (metal electrical connection layer 104), electrical insulation function (organic insulating film 103) and heat dissipation function (heat dissipation substrate 102) without welding or sintering process.

[0041] The metal electrical connection layer 104 includes a functional circuit pattern and is responsible for the transmission connection of power signals and control signals of the power module; the material of the metal electrical connection layer 104 is copper.

[0042] The material of the organic insulating film 103 is a polymer epoxy resin, or a composite insulating material composed of a polymer epoxy resin and an inorganic material, and the thickness thereof can be adjusted according to the insulation requirements.

[0043] The heat dissipation substrate 102 is made of copper or aluminum, and its surface is plated with an anti-oxidation material such as nickel, chromium, etc.

[0044] The power terminal 01 and the signal terminal 02 are electrically connected to the metal electrical connection layer 104 through a reflow process, and a terminal welding layer 03 is formed.

[0045] Figure 5 It is a copper clip structure. The copper clip will form an integrated interconnection between the upper surfaces of chips with the same function and connect them to the metal electrical connection layer. The copper clip 04 connects it to the chip 07 and the metal electrical connection layer 104 through the copper clip welding layer 05, so that it has the power electrical signal connection and transmission function. Compared with the traditional metal bonding wire electrical connection method, the copper clip structure has lower parasitic parameters, which is conducive to fully exerting the performance of the power module, such as lower current and voltage overshoot risks in the switching process and smaller switching losses.

[0046] Figure 6 In the figure, A is the chip connection plane, B is the bending plane, and C is the metal electrical connection layer connection plane; the thickness of the copper clip is 0.08mm-0.15mm, and the edge of the copper clip has a 45°-90° bend. The copper clip includes 3 planes, including the chip connection plane, the bending plane and the metal electrical connection layer connection plane; the edge of the chip connection plane of the copper clip has a 45°-90° bend, the purpose of which is to improve the stress on the chip during assembly.

[0047] The metal bonding wire 06 connects the chip 07 and the metal electrical connection layer 104 by ultrasonic bonding, thereby completing the electrical connection function of the control signal.

[0048] The above chip 07 is a power chip, such as IGBT, FRD, or SiC MOSFET chip.

[0049] The power chip is fixed to the metal electrical connection layer 104 by welding or sintering to complete the power signal connection and form the chip welding layer 08 .

[0050] The specific embodiment relates to an IGBT half-bridge inverter power module.

[0051] The power module needs to be electrically connected to the outside through terminals, and this embodiment includes power terminals 01 and signal terminals 02; the power terminals 01 and signal terminals 02 are fixed to the metal electrical connection layer 104 of the organic insulating film integrated substrate 09 through the terminal welding layer 03, and form an electrical circuit; the power terminal includes three independent terminals, namely the DC positive terminal (left), the DC negative terminal (middle) and the AC output terminal (right); the signal terminal includes four independent terminals, namely the gate-level control terminal and the Kelvin terminal of the upper (lower) bridge;

[0052] In order to realize the power connection inside the power module, in this embodiment, the control signal part is connected by ultrasonic bonding of metal bonding wire 06; the power circuit part is connected by welding of copper clip 04, and copper clip 04 is fixed to the upper surface of IGBT chip and FRD chip and metal electrical connection layer 104 of organic insulating film integrated substrate 09 through copper clip welding layer 05 to form an electrical circuit; copper clip 04 includes two parts, the second copper clip 101 is responsible for the partial electrical connection function between the upper surface of upper bridge chip and the lower surface of lower bridge chip and AC output terminal; the first copper clip 100 is responsible for the partial electrical connection function between the upper surface of lower bridge chip and DC negative terminal; compared with the traditional metal wire bonding connection method, the copper clip 04 structure can reduce parasitic parameters and improve the adverse effects of parasitic parameters;

[0053] The chip 07 structure of this embodiment includes 6 groups of chips, each group of chips includes a 1200V / 150A IGBT chip and a FRD chip of the same specification; three groups of chips are connected in parallel to form an upper bridge, and the other three groups of chips are connected in parallel to form a lower bridge; the parallel design can improve the current carrying capacity of the power module; through this parallel design, the current carrying capacity of the power module of the embodiment can reach 450A;

[0054] The lower surface of the chip 07 of this embodiment is electrically connected to the metal electrical connection layer 104 of the organic insulating film integrated substrate 09 through the chip welding layer 08;

[0055] The organic insulating film integrated substrate 09 of this embodiment includes a three-layer structure, namely a heat dissipation substrate 102, an organic insulating film 103, and a metal electrical connection layer 104. The three-layer structure is formed by hot pressing. In traditional power modules, the ceramic substrate needs to be fixed to the heat dissipation substrate by welding or sintering. The upper metal layer of the ceramic substrate is responsible for electrical connection, the ceramic layer is responsible for electrical insulation, the lower metal layer is responsible for welding or sintering with the heat dissipation substrate, and the heat dissipation substrate is responsible for transferring heat to the external environment. The organic insulating film integrated substrate 09 has electrical connection function (metal electrical connection layer 104), electrical insulation function (organic insulating film 103) and heat dissipation function (heat dissipation substrate 102) without welding or sintering process in the power module packaging stage.

[0056] The present invention also discloses a method for manufacturing a power module without a ceramic substrate, comprising:

[0057] An insulating integrated substrate is manufactured by a hot pressing integrated forming method, wherein the insulating integrated substrate comprises a heat dissipation substrate, an insulating substrate, and a metal electrical connection layer which are sequentially arranged from bottom to top;

[0058] Using a reflow soldering process, the power terminal and the signal terminal are electrically connected to the metal electrical connection layer through the first soldering layer;

[0059] The electrical connection component is connected to the chip and the metal electrical connection layer respectively through the second welding layer, and the edge of the electrical connection component is bent with a certain arc;

[0060] Connecting the chip to the metal electrical connection layer using metal bonding wires by ultrasonic bonding;

[0061] The chip is fixed to the metal electrical connection layer through the third welding layer.

[0062] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A power module without ceramic substrate, characterized in that: It includes a power terminal, a signal terminal, a first welding layer, a first electrical connection component, a second welding layer, a second electrical connection component, a chip, a third welding layer and an insulating integrated substrate; the edge of the first electrical connection component is bent with a certain arc; wherein, The insulating integrated substrate includes a heat dissipation substrate, an insulating substrate, and a metal electrical connection layer which are sequentially arranged from bottom to top. The heat dissipation substrate, the insulating substrate, and the metal electrical connection layer are integrally formed by hot pressing, wherein: The power terminal and the signal terminal are electrically connected to the metal electrical connection layer through the first welding layer respectively; The first electrical connection component is connected to the chip and the metal electrical connection layer respectively through the second welding layer to form an internal power electrical circuit of the power module; The chip is connected to the metal electrical connection layer through the second electrical connection component to form an internal control electrical circuit of the power module; The chip is fixed on the metal electrical connection layer through a third welding layer.

2. A ceramic substrate-free power module according to claim 1, characterized in that: The first electrical connection component is a copper clip, the edge of which is bent at 45°-90°, and the thickness of the copper clip is 0.08mm-0.15mm.

3. A ceramic substrate-free power module according to claim 2, characterized in that: The copper clip comprises a chip connection plane, a bending plane and a metal electrical connection layer connection plane, and the edge of the chip connection plane of the copper clip is bent at 45°-90°.

4. The ceramic-free substrate power module according to claim 1, characterized in that: The insulating integrated substrate is an organic insulating film integrated substrate, the insulating substrate is an organic insulating film, and the thickness of the insulating substrate is 0.05mm-0.2mm.

5. The ceramic-free substrate power module according to claim 1, characterized in that: The first welding layer is a terminal welding layer, the second welding layer is a copper clip welding layer, the third welding layer is a chip welding layer, and the second electrical connection component is a metal bonding wire.

6. The ceramic-free substrate power module according to claim 1, characterized in that: A functional circuit pattern is provided on the metal electrical connection layer. The power terminal and the signal terminal are used for electrical connection with the outside. The shape of the power terminal is a "X" shape.

7. The ceramic-free substrate power module according to claim 1, characterized in that: The surface of the heat dissipation substrate is also coated with an anti-oxidation layer.

8. The ceramic-free substrate power module according to claim 1, characterized in that: The chip is a power chip, and the power chip includes an IGBT, FRD or SiC MOSFET chip.

9. The ceramic-substrate-free power module according to claim 4, characterized in that: The material of the organic insulating film is high molecular epoxy resin, the material of the heat dissipation substrate is copper or aluminum, and the material of the metal electrical connection layer is copper.

10. A method for manufacturing a power module without a ceramic substrate, characterized in that: include: An insulating integrated substrate is manufactured by a hot pressing integrated forming method, wherein the insulating integrated substrate comprises a heat dissipation substrate, an insulating substrate, and a metal electrical connection layer which are sequentially arranged from bottom to top; Using a reflow soldering process, the power terminal and the signal terminal are electrically connected to the metal electrical connection layer through the first soldering layer; The electrical connection component is connected to the chip and the metal electrical connection layer respectively through the second welding layer, and the edge of the electrical connection component is bent with a certain arc; Connecting the chip to the metal electrical connection layer using metal bonding wires by ultrasonic bonding; The chip is fixed to the metal electrical connection layer through the third welding layer.

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