Intelligent power module and preparation method thereof
Technical Field
The invention relates to the technical field of power device packaging, in particular to an intelligent power module and a preparation method thereof.
Background
Intelligent Power Module (IPM) is an abbreviation of Intelligent Power Module, a Power-driven semiconductor-like package combining Power electronics and integrated circuit technology. Compared with the traditional discrete semiconductor packaging structure, the intelligent power module is more and more widely applied due to the advantages of high integration degree, high reliability and the like. In a conventional smart power module, various electronic components are generally mounted on a substrate having a planar structure, and as a semiconductor package structure is developed toward miniaturization and integration, it is a problem that more and more technicians pay attention to how to improve the integration level of the smart power module and reduce the size of the smart power module.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides an intelligent power module and a preparation method thereof.
In order to achieve the above object, the present invention provides a method for manufacturing an intelligent power module, comprising the following steps:
1) providing a metal substrate, forming a plurality of strip-shaped bumps arranged side by side on the upper surface of the metal substrate, wherein each strip-shaped bump is provided with two inclined side surfaces, the included angle between each inclined side surface and the bottom surface of each strip-shaped bump is 30-60 degrees, and a plurality of grooves are formed on each inclined side surface;
2) forming a plurality of concave holes which are arranged in an array on the lower surface of the metal substrate;
3) then depositing an insulating material on the upper surface of the metal substrate to form an insulating layer, wherein part of the insulating layer covers the bottom surface and the side surface of each groove;
4) forming a plurality of metal bumps, wherein each metal bump is embedded into the corresponding groove to form a circuit wiring structure;
5) mounting a plurality of electronic components and a plurality of pins on the circuit wiring structure;
6) placing the metal substrate assembled with the electronic element and the pins in a mold, firstly injecting a certain amount of heat-conducting resin material to form a first heat-conducting sealing adhesive layer, wherein the concave holes are filled with the first heat-conducting sealing adhesive layer, the first heat-conducting sealing adhesive layer only covers the lower end part of the metal substrate, and then injecting a certain amount of heat-insulating resin material to form a first heat-insulating sealing adhesive layer, the first heat-insulating sealing adhesive layer is laid on the first heat-conducting sealing adhesive layer, the first heat-insulating sealing adhesive layer completely covers the strip-shaped bumps and the electronic element, and the first heat-insulating sealing adhesive layer covers part of the pins; then injecting a certain amount of heat-conducting resin material to form a second heat-conducting sealing adhesive layer, wherein the second heat-conducting sealing adhesive layer is laid on the first heat-insulating sealing adhesive layer;
7) removing part of the first heat-insulating sealant layer and the second heat-conducting sealant layer to form a blind hole above each of the electronic components, wherein the bottom surface of each blind hole is parallel to the top surface of the corresponding power component, and then tightly embedding a heat dissipation block into the blind hole, so that the thickness of the heat-insulating sealant layer between the bottom surface of the heat dissipation block and the top surface of the power component is less than 200 microns;
8) and removing part of the first heat conduction sealing adhesive layer to expose part of the lower surface of the metal substrate.
As above method for manufacturing the intelligent power module, in the step 1, the metal substrate is made of one of aluminum, copper and stainless steel, the bar-shaped protrusion is formed by a cutting process, the groove is formed by wet etching or dry etching, and the depth of the groove is 100-200 μm.
In the above method for manufacturing an intelligent power module, further, in step 2, the concave holes are formed by wet etching or dry etching, the depth of each concave hole is 0.5-1 mm, the diameter of each concave hole is 1-2 mm, and the distance between every two adjacent concave holes is 3-5 mm.
As the above method for manufacturing the smart power module, further, in the step 3, silicon nitride, boron nitride or silicon carbide is deposited by a PECVD method to form the insulating layer, or aluminum oxide is deposited by an ALD method to form the insulating layer, and the thickness of the insulating layer is 40-80 μm.
As above, in the preparation method of the intelligent power module, further, in the step 4, the material copper of the metal bump is formed into a plurality of metal bumps through a stamping or cutting process, and the thickness of the metal bumps is 200-300 μm.
In the above method for manufacturing a smart power module, further, in step 5, the electronic component is mounted on the circuit wiring structure by a flip-chip process, and the pins are mounted on the pin pads in the circuit wiring structure by a soldering process.
In the above method for manufacturing an intelligent power module, further, in step 6, the heat-conductive resin material comprises the following components in percentage by weight: 20-30 parts of ABS resin, 30-40 parts of PBT resin, 10-20 parts of polycarbonate, 5-15 parts of polyamide, 3-8 parts of alumina powder, 2-6 parts of boron nitride powder, 1-6 parts of magnesium oxide powder, 2-5 parts of silicon nitride powder and 2-6 parts of silicon carbide powder; the heat-insulating resin material comprises the following components in percentage by weight: 20-30 parts of ABS resin, 30-40 parts of PBT resin, 10-20 parts of polycarbonate, 5-15 parts of polyamide, 2-10 parts of glass fiber, 2-8 parts of aluminum silicate powder, 2-6 parts of expanded perlite powder and 2-5 parts of magnesium silicate powder.
In the above method for manufacturing an intelligent power module, in step 7, the material of the heat dissipation block is one of graphite, copper, and aluminum.
The invention also provides an intelligent power module which is prepared by adopting the method.
Compared with the prior art, the invention has the beneficial effects that:
through the upper surface at metal substrate be formed with a plurality of bar lugs that set up side by side to with electronic component assembly on the slope side surface of bar lug, effectively reduced intelligent power module's size, further optimize the slope side surface with the number of degrees of the contained angle of the bottom surface of bar lug obtains the intelligent power module that a bottom surface area and thickness are all suitable. The first heat-conducting sealing adhesive layer, the first heat-insulating sealing adhesive layer and the second heat-conducting sealing adhesive layer which are overlapped are used as the sealing adhesive layer of the intelligent power module, wherein the first heat-insulating sealing adhesive layer completely covers the strip-shaped convex blocks and the electronic elements, heat can be effectively prevented from being diffused in the first heat-insulating sealing adhesive layer, the influence of the diffused heat on the performance of non-power elements in the electronic elements is further avoided, the excellent sealing performance of each sealing adhesive layer is ensured by optimizing the components and the content of each sealing resin material, the invasion of moisture is effectively prevented, the service life of the intelligent power module is further prolonged, the heat-conducting block is formed above each power element, the lower part of each power element is borne by the metal substrate, a double-sided heat dissipation structure is formed, and the heat dissipation performance of the intelligent power module is effectively improved. In addition, the preparation method of the intelligent power module is simple and easy to implement, is compatible with the process of the existing intelligent power module, and is convenient for large-scale industrial production.
Drawings
Fig. 1 is a schematic structural diagram of an intelligent power module according to the present invention.
Fig. 2 is a bottom view of the smart power module of the present invention.
Detailed Description
As shown in fig. 1-2, the present invention provides an intelligent power module, which includes a metal substrate 1, a plurality of bar-shaped bumps 11 arranged side by side are formed on an upper surface of the metal substrate 1, each of the bar-shaped bumps 11 has two inclined side surfaces, an included angle between the inclined side surface and a bottom surface of the bar-shaped bump 11 is 30 ° -60 °, a plurality of grooves 12 are formed on each of the inclined side surfaces, a plurality of concave holes 13 arranged in an array are formed on a lower surface of the metal substrate 1, an insulating layer 2 is formed on the upper surface of the metal substrate, a portion of the insulating layer 2 covers a bottom surface and a side surface of each of the grooves 12, a plurality of metal bumps are formed, each of the metal bumps is embedded in the corresponding groove 12 to form a circuit wiring structure 3, a plurality of electronic components 4 and a plurality of pins 5 are mounted on the circuit wiring structure 3, the first heat-conducting sealing adhesive layer 6 is full of the concave hole 13, the first heat-conducting sealing adhesive layer 6 only covers the lower end part of the metal substrate 1, the first heat-insulating sealing adhesive layer 7 is laid on the first heat-conducting sealing adhesive layer 6, the first heat-insulating sealing adhesive layer 7 completely covers the strip-shaped convex block 11 and the electronic element 4, and the first heat-insulating sealing adhesive layer 7 covers part of the pins 5; a second heat-conducting sealant layer 8, wherein the second heat-conducting sealant layer 8 is laid on the first heat-insulating sealant layer 7, a portion of the first heat-insulating sealant layer 7 and a portion of the second heat-conducting sealant layer 8 are removed, so as to form a blind hole 9 above each of the electronic components 4, a bottom surface of each blind hole is parallel to a top surface of the corresponding power component, and then a heat dissipation block 91 is tightly embedded in the blind hole 9, so that the thickness of the heat-insulating sealant layer between the bottom surface of the heat dissipation block 91 and the top surface of the power component is less than 200 micrometers; a portion of the first heat conductive sealant layer 6 is removed to form a hole 61 exposing a portion of the lower surface of the metal substrate.
The invention also provides a preparation method of the intelligent power module, which comprises the following steps:
1) providing a metal substrate, forming a plurality of strip-shaped convex blocks arranged side by side on the upper surface of the metal substrate, wherein each strip-shaped convex block is provided with two inclined side surfaces, the included angle between each inclined side surface and the bottom surface of each strip-shaped convex block is 30-60 degrees, the included angle between each inclined side surface and the bottom surface of each strip-shaped convex block is less than 30 degrees, the area of the bottom surface of the corresponding intelligent power module cannot be sufficiently reduced, the included angle between each inclined side surface and the bottom surface of each strip-shaped convex block is more than 60 degrees, so that the corresponding intelligent power module is too thick, a plurality of grooves are formed on each inclined side surface, the metal substrate is made of one of aluminum, copper and stainless steel, the strip-shaped convex blocks are formed through a cutting process, the grooves are formed through wet etching or dry etching, the depth of the grooves is 100-200 microns, and the existence of the grooves can firmly fix a circuit wiring, thereby preventing the circuit wiring structure from peeling;
2) forming a plurality of concave holes which are arranged in an array on the lower surface of the metal substrate, and forming the concave holes through wet etching or dry etching, wherein the depth of each concave hole is 0.5-1 mm, the diameter of each concave hole is 1-2 mm, and the distance between every two adjacent concave holes is 3-5 mm, so that the bonding strength between a first heat-conducting sealing adhesive layer formed subsequently and the metal substrate is improved, and the sealing performance and the moisture resistance of the whole intelligent power module are further improved;
3) then depositing an insulating material on the upper surface of the metal substrate to form an insulating layer, wherein part of the insulating layer covers the bottom surface and the side surface of each groove, depositing silicon nitride, boron nitride or silicon carbide by a PECVD (plasma enhanced chemical vapor deposition) method to form the insulating layer, or depositing aluminum oxide by an ALD (atomic layer deposition) method to form the insulating layer, wherein the thickness of the insulating layer is 40-80 microns, so that the insulating property and the heat conducting property between the metal substrate and a circuit wiring structure are improved, and heat generated when a power element works can be rapidly transferred to the metal substrate;
4) forming a plurality of metal bumps, wherein each metal bump is embedded into the corresponding groove to form a circuit wiring structure, the material copper of the metal bumps is used for forming the plurality of metal bumps through a stamping or cutting process, and the thickness of each metal bump is 200-300 microns;
5) mounting a plurality of electronic components and a plurality of pins on the circuit wiring structure, the electronic components being mounted on the circuit wiring structure by a flip-chip process, the pins being mounted on pin pads in the circuit wiring structure by a soldering process;
6) placing the metal substrate assembled with the electronic element and the pins in a mold, firstly injecting a certain amount of heat-conducting resin material to form a first heat-conducting sealing adhesive layer, wherein the concave holes are filled with the first heat-conducting sealing adhesive layer, the first heat-conducting sealing adhesive layer only covers the lower end part of the metal substrate, and then injecting a certain amount of heat-insulating resin material to form a first heat-insulating sealing adhesive layer, the first heat-insulating sealing adhesive layer is laid on the first heat-conducting sealing adhesive layer, the first heat-insulating sealing adhesive layer completely covers the strip-shaped bumps and the electronic element, and the first heat-insulating sealing adhesive layer covers part of the pins; then injecting a certain amount of heat-conducting resin material to form a second heat-conducting sealing adhesive layer, wherein the second heat-conducting sealing adhesive layer is laid on the first heat-insulating sealing adhesive layer, and the heat-conducting resin material comprises the following components in percentage by weight: 20-30 parts of ABS resin, 30-40 parts of PBT resin, 10-20 parts of polycarbonate, 5-15 parts of polyamide, 3-8 parts of alumina powder, 2-6 parts of boron nitride powder, 1-6 parts of magnesium oxide powder, 2-5 parts of silicon nitride powder and 2-6 parts of silicon carbide powder; the heat-insulating resin material comprises the following components in percentage by weight: 20-30 parts of ABS resin, 30-40 parts of PBT resin, 10-20 parts of polycarbonate, 5-15 parts of polyamide, 2-10 parts of glass fiber, 2-8 parts of aluminum silicate powder, 2-6 parts of expanded perlite powder and 2-5 parts of magnesium silicate powder, wherein a first heat conduction sealing adhesive layer, a first heat insulation sealing adhesive layer and a second heat conduction sealing adhesive layer which are overlapped are arranged as sealing adhesive layers of the intelligent power module, the first heat insulation sealing adhesive layer completely covers the strip-shaped bump and the electronic element, heat can be effectively prevented from being diffused in the first heat insulation sealing adhesive layer, the performance of a non-power element in the electronic element is further prevented from being influenced by the diffused heat, and the comprehensive performance of the intelligent power module is effectively improved by optimizing the components and the content of each sealing resin material;
7) removing part of the first heat-insulation sealant layer and the second heat-conduction sealant layer to form a blind hole above each power element in the electronic elements, wherein the bottom surface of each blind hole is parallel to the top surface of the corresponding power element, and then a heat dissipation block is tightly embedded into the blind hole, so that the thickness of the heat-insulation sealant layer between the bottom surface of the heat dissipation block and the top surface of the power element is less than 200 microns, the heat dissipation block is made of one of graphite, copper and aluminum, and the heat dissipation performance of the intelligent power module is effectively improved;
8) and removing part of the first heat conduction sealing adhesive layer to expose part of the lower surface of the metal substrate.
Example 1
The invention provides a preparation method of an intelligent power module, which comprises the following steps:
1) providing a metal substrate, forming a plurality of strip-shaped convex blocks arranged side by side on the upper surface of the metal substrate, wherein each strip-shaped convex block is provided with two inclined side surfaces, the included angles between the inclined side surfaces and the bottom surfaces of the strip-shaped convex blocks are 45 degrees, a plurality of grooves are formed on each inclined side surface, the metal substrate is made of aluminum, the strip-shaped convex blocks are formed through a cutting process, the grooves are formed through wet etching, and the depth of each groove is 150 micrometers;
2) forming a plurality of concave holes in array arrangement on the lower surface of the metal substrate, and forming the concave holes through wet etching, wherein the depth of each concave hole is 0.8 mm, the diameter of each concave hole is 1.5 mm, and the distance between every two adjacent concave holes is 4 mm;
3) depositing an insulating material on the upper surface of the metal substrate to form an insulating layer, wherein part of the insulating layer covers the bottom surface and the side surface of each groove, and depositing silicon nitride by a PECVD method to form the insulating layer, wherein the thickness of the insulating layer is 60 microns;
4) forming a plurality of metal bumps, wherein each metal bump is embedded into the corresponding groove to form a circuit wiring structure, the metal bumps are made of copper, the plurality of metal bumps are formed through a stamping process, and the thickness of each metal bump is 250 micrometers;
5) mounting a plurality of electronic components and a plurality of pins on the circuit wiring structure, the electronic components being mounted on the circuit wiring structure by a flip-chip process, the pins being mounted on pin pads in the circuit wiring structure by a soldering process;
6) placing the metal substrate assembled with the electronic element and the pins in a mold, firstly injecting a certain amount of heat-conducting resin material to form a first heat-conducting sealing adhesive layer, wherein the concave holes are filled with the first heat-conducting sealing adhesive layer, the first heat-conducting sealing adhesive layer only covers the lower end part of the metal substrate, and then injecting a certain amount of heat-insulating resin material to form a first heat-insulating sealing adhesive layer, the first heat-insulating sealing adhesive layer is laid on the first heat-conducting sealing adhesive layer, the first heat-insulating sealing adhesive layer completely covers the strip-shaped bumps and the electronic element, and the first heat-insulating sealing adhesive layer covers part of the pins; then injecting a certain amount of heat-conducting resin material to form a second heat-conducting sealing adhesive layer, wherein the second heat-conducting sealing adhesive layer is laid on the first heat-insulating sealing adhesive layer, and the heat-conducting resin material comprises the following components in percentage by weight: 25 parts of ABS resin, 35 parts of PBT resin, 15 parts of polycarbonate, 10 parts of polyamide, 5 parts of alumina powder, 4 parts of boron nitride powder, 4 parts of magnesium oxide powder, 4 parts of silicon nitride powder and 3 parts of silicon carbide powder; the heat-insulating resin material comprises the following components in percentage by weight: 25 parts of ABS resin, 40 parts of PBT resin, 18 parts of polycarbonate, 12 parts of polyamide, 5 parts of glass fiber, 5 parts of aluminum silicate powder, 4 parts of expanded perlite powder and 3 parts of magnesium silicate powder;
7) removing part of the first heat-insulating sealant layer and the second heat-conducting sealant layer to form a blind hole above each power element in the electronic elements, wherein the bottom surface of each blind hole is parallel to the top surface of the corresponding power element, and then tightly embedding a heat dissipation block into the blind hole, so that the thickness of the heat-insulating sealant layer between the bottom surface of the heat dissipation block and the top surface of the power element is 150 microns, and the heat dissipation block is made of copper;
8) and removing part of the first heat conduction sealing adhesive layer to expose part of the lower surface of the metal substrate.
Example 2
The invention provides a preparation method of an intelligent power module, which comprises the following steps:
1) providing a metal substrate, forming a plurality of strip-shaped convex blocks arranged side by side on the upper surface of the metal substrate, wherein each strip-shaped convex block is provided with two inclined side surfaces, the included angle between each inclined side surface and the bottom surface of each strip-shaped convex block is 60 degrees, a plurality of grooves are formed on each inclined side surface, the metal substrate is made of copper, the strip-shaped convex blocks are formed through a cutting process, the grooves are formed through dry etching, and the depth of each groove is 100 micrometers;
2) forming a plurality of concave holes in array arrangement on the lower surface of the metal substrate, and forming the concave holes through dry etching, wherein the depth of each concave hole is 1 mm, the diameter of each concave hole is 1 mm, and the distance between every two adjacent concave holes is 3 mm;
3) then depositing an insulating material on the upper surface of the metal substrate to form an insulating layer, wherein part of the insulating layer covers the bottom surface and the side surface of each groove, and depositing silicon carbide by a PECVD method to form the insulating layer, wherein the thickness of the insulating layer is 40 microns;
4) forming a plurality of metal bumps, wherein each metal bump is embedded into the corresponding groove to form a circuit wiring structure, the metal bumps are made of copper, the plurality of metal bumps are formed through a cutting process, and the thickness of each metal bump is 200 microns;
5) mounting a plurality of electronic components and a plurality of pins on the circuit wiring structure, the electronic components being mounted on the circuit wiring structure by a flip-chip process, the pins being mounted on pin pads in the circuit wiring structure by a soldering process;
6) placing the metal substrate assembled with the electronic element and the pins in a mold, firstly injecting a certain amount of heat-conducting resin material to form a first heat-conducting sealing adhesive layer, wherein the concave holes are filled with the first heat-conducting sealing adhesive layer, the first heat-conducting sealing adhesive layer only covers the lower end part of the metal substrate, and then injecting a certain amount of heat-insulating resin material to form a first heat-insulating sealing adhesive layer, the first heat-insulating sealing adhesive layer is laid on the first heat-conducting sealing adhesive layer, the first heat-insulating sealing adhesive layer completely covers the strip-shaped bumps and the electronic element, and the first heat-insulating sealing adhesive layer covers part of the pins; then injecting a certain amount of heat-conducting resin material to form a second heat-conducting sealing adhesive layer, wherein the second heat-conducting sealing adhesive layer is laid on the first heat-insulating sealing adhesive layer, and the heat-conducting resin material comprises the following components in percentage by weight: 30 parts of ABS resin, 30 parts of PBT resin, 20 parts of polycarbonate, 15 parts of polyamide, 8 parts of alumina powder, 2 parts of boron nitride powder, 2 parts of magnesium oxide powder, 5 parts of silicon nitride powder and 2 parts of silicon carbide powder; the heat-insulating resin material comprises the following components in percentage by weight: 30 parts of ABS resin, 30 parts of PBT resin, 20 parts of polycarbonate, 12 parts of polyamide, 4 parts of glass fiber, 2 parts of aluminum silicate powder, 2 parts of expanded perlite powder and 4 parts of magnesium silicate powder, wherein the first heat-conducting sealing adhesive layer, the first heat-insulating sealing adhesive layer and the second heat-conducting sealing adhesive layer which are overlapped are arranged to serve as sealing adhesive layers of the intelligent power module, the first heat-insulating sealing adhesive layer completely covers the strip-shaped bump and the electronic element, heat can be effectively prevented from being diffused in the first heat-insulating sealing adhesive layer, the performance of a non-power element in the electronic element is further prevented from being influenced by the diffused heat, and the total amount and the performance of the intelligent power module are effectively improved by optimizing the components and the content of each sealing resin material;
7) removing part of the first heat-insulating sealant layer and the second heat-conducting sealant layer to form a blind hole above each power element in the electronic elements, wherein the bottom surface of each blind hole is parallel to the top surface of the corresponding power element, and then a heat dissipation block is tightly embedded into the blind hole, so that the thickness of the heat-insulating sealant layer between the bottom surface of the heat dissipation block and the top surface of the power element is 100 microns, the heat dissipation block is made of graphite, and the heat dissipation performance of the intelligent power module is effectively improved;
8) and removing part of the first heat conduction sealing adhesive layer to expose part of the lower surface of the metal substrate.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.