CN111261601A - Clamp embedded type high-integration-level compression joint type packaged power module - Google Patents

Abstract

The invention discloses a clamp-embedded high-integration crimping package power module, which comprises a positive heat sink, a DC positive copper bar, an AC output copper bar, a DC negative copper bar and a negative electrode sequentially arranged from top to bottom Heat sink; semiconductor chip units are symmetrically installed on both sides of the AC output copper bar, and the periphery of the semiconductor chip unit is evenly distributed with threaded holes penetrating the crimping module, which are fastened by insulating double-headed screws. The external thread on the threaded hole is engaged with the internal thread of the threaded hole to generate a crimping force; the present invention adopts an embedded clamp to realize the crimping of the module, and uses the copper bar and the heat sink as the component parts of the module, thus realizing high power density and high integration; Compared with the traditional press-fit packaged power module, the technical solution of the present invention reduces the design cost and simplifies the manufacturing process due to the optimized fixture design, and the press-fit packaged power module is used to realize a high power density rectifier.

Description

A clamp-embedded high-integration press-fit packaged power module

technical field

The invention belongs to the technical field of power electronic devices, and in particular relates to a clamp-embedded high-integration crimping package power module.

Background technique

Compared with plastic sealing and soldering packaging technology, press-fit packaging technology has application characteristics such as wire-free bonding, no solder layer, double-sided heat dissipation, and short-circuit failure. High-power semiconductor modules made of this packaging technology, such as thyristor (SCR) ), Integrated Gate Commutated Thyristor (IGCT), Crimp Insulated Gate Bipolar Transistor (IGBT), etc., which have the advantages of low thermal impedance, wide safe working area and high rated power, and are widely used in flexible DC power transmission, high-speed rail Traffic, long-distance wind power generation and other occasions with complex working conditions, harsh environment and high reliability requirements.

Due to the particularity of the crimping packaging technology, in order to achieve a reliable electrical connection inside the module and between the modules, a pressure of 10-20 MPa needs to be applied to the module chip. As shown in FIG. 1 is a typical crimping force realization fixture structure applied in an existing commercial crimping module, including a fastening bolt 1, a support plate 2, a fastening stud 3, and a disc spring group 4 , Bearing plate 5, radiator 6, crimping module 7 and other parts. The disc spring group 4 is formed by stacking several identical disc springs to meet the crimping force required by the crimping module 7 . Fastening studs 1 are placed vertically at the four corners outside the crimping module 7, and the deformation of the disc spring group 4 is fixed through the support plate 2 and the fastening studs 3, so that the disc spring group 4 is kept in a compressed state and maintained crimp force.

Although the clamp can achieve pressurization and maintain pressure, there are still the following shortcomings that need to be improved: (1) The clamp needs a support plate and a load-bearing plate that are similar in size to the crimping module, and additional fasteners and disc springs are required. (2) Due to the centralized pressure maintenance method, the pressure between the chips inside the crimping module is unbalanced, and the chips in the center of the module are subjected to greater stress and the edge of the module The chip in the position is less stressed; (3) Due to the complex design of the fixture, the operation accuracy is high, and the pressure of the chip is not balanced. Once the operation is wrong, the center chip will be damaged or the edge chip connection will be invalid.

SUMMARY OF THE INVENTION

In view of the above problems, the present invention provides a clamp-embedded high-integration crimping package power module, which removes the traditional crimping clamp of the outer frame, and uses conductive copper bars and heat-dissipating aluminum sheets directly as pressure contacts. Double-headed cylindrical screws are embedded in the module, which are evenly distributed around the chip to apply and maintain the required crimping force for the chip.

In order to achieve the above purpose, the present invention provides a clamp-embedded high-integration crimp-type packaged power module, comprising a positive heat sink, a pressure-connected module and a negative heat sink connected in sequence from top to bottom; the The crimping module includes a DC positive copper bar, an AC output copper bar, a DC negative copper bar and a semiconductor chip unit.

The two sides of the AC output copper bar are symmetrically installed with semiconductor chip units, and the periphery of the semiconductor chip unit is evenly distributed with threaded holes penetrating the DC positive copper bar, the AC output copper bar and the DC negative copper bar, which are fastened by insulating double-headed screws. The crimping force is generated by the engagement of the external thread on the insulating double-headed screw with the internal thread of the threaded hole; the upper and lower surfaces of the DC positive copper bar and the DC negative copper bar are provided with insulating films, and the DC positive copper bar and the DC negative copper bar are provided with insulating films. There is a DC bus capacitor interface on the row, and a load interface on the AC output copper row.

As a preferred option of the present invention, the upper and lower surfaces of the AC output copper bars are symmetrically provided with a positioning groove 1 and a positioning groove 2 for mounting the semiconductor chip unit, the positive electrode of the semiconductor chip unit is closely attached to the positioning groove 2, and the negative electrode It is closely attached to the positioning groove 1; the insulating film of the lower layer of the DC positive copper bar and the upper insulating film of the DC negative copper bar are provided with through holes for the semiconductor chip units to pass through.

As a preference of the present invention, the height of the insulating double-headed screw is flush with the upper surface of the DC positive electrode copper bar and the lower surface of the AC output copper bar.

As a preferred option of the present invention, the semiconductor chip unit is an integrated laminate assembly formed from top to bottom by an upper molybdenum sheet, a semiconductor chip, a lower molybdenum sheet and an aluminum sheet; the positive electrode of the semiconductor chip is crimped to the upper molybdenum sheet contact, and the negative electrode is in crimp contact with the lower molybdenum sheet.

As a preference of the present invention, the thickness of the upper molybdenum sheet and the lower molybdenum sheet is 100 μm˜400 μm, and the thickness of the aluminum sheet is 50 μm˜200 μm.

As a preferred option of the present invention, the semiconductor chip is a silicon diode chip, a Schottky diode chip, a silicon carbide diode chip or a silicon carbide diode chip.

As a preferred aspect of the present invention, the semiconductor chip unit is provided with a stepped limit structure, the lower insulating film of the DC positive copper bar and the upper insulating film of the DC negative copper bar are provided with stepped holes for the semiconductor chip units to pass through, and the stepped holes are connected to the Ladder limit structure matching.

As a preference of the present invention, the insulating double-ended screw is made of polyether ether ketone, and the insulating film is made of polyethylene terephthalate.

As a preference of the present invention, the thickness of each insulating film is more than 50 μm.

As a preferred option of the present invention, the positive heat sink, the crimping module and the negative heat sink are provided with through threaded holes, which are fastened by elongated insulating double-headed screws.

Compared with the prior art, the present invention has the following advantages:

(1) The power module in the present invention cancels the outer frame fixtures such as disc springs, support plates, and load-bearing plates, and adopts embedded high-strength double-headed screws to distribute around the chip to ensure the crimping force and improve the module power density. .

(2) In the present invention, the positive and negative copper bars of the DC side are crimped to form a laminated structure, and the insulating film is used to ensure the dielectric strength, which reduces the stray parameters of the power circuit while ensuring safe application.

(3) In the present invention, the heat sink is attached to the surface of the DC copper bar, which realizes the double-sided heat dissipation feature of the crimping package module and reduces the overall thermal impedance of the module.

(4) Double-headed screws are evenly distributed around the chip units to be pressed in parallel in the present invention, the rotational torque is converted into pressure, and the chip units are fastened and crimped by copper bars, which not only ensures the uniform pressure on a single chip, but also ensures that the parallel connection The pressure distribution between the pressed chip units is uniform. Through the evenly distributed mechanical crimping stress, the uniform distribution of the contact thermal resistance and the contact resistance between the chip and the copper bar is ensured, avoiding the appearance of extreme temperature hot spots during the application process, and making the crimping package module in the case of multi-chip parallel connection. still maintain high reliability.

Description of drawings

FIG. 1 is a schematic structural diagram of a traditional typical crimping force realization fixture;

FIG. 2 is a schematic structural exploded view of a specific embodiment of a high-integration press-fit packaged power module according to the present invention;

3 is a schematic cross-sectional view of the overall structure of a specific embodiment of a high-integration press-fit packaged power module according to the present invention;

4 is a schematic cross-sectional view of a partial structure of a specific embodiment of a high-integration press-fit packaged power module according to the present invention;

In the picture: 1- Fastening bolt, 2- Support plate, 3- Fastening stud, 4- Disc spring group, 5- Bearing plate, 6- Radiator, 7- Crimp module, 8- Positive heat sink , 9-extended insulating double-headed screw, 10-DC positive copper bar upper insulating film, 11-DC positive copper bar, 12-insulated double-headed screw, 13-DC positive copper bar lower insulating film, 14-semiconductor chip unit, 15- AC output copper bar, 16- AC output copper bar upper insulating film, 17- DC negative copper bar, 18- AC output copper bar lower insulating film, 19- Negative heat sink, 20- Upper molybdenum sheet, 21- Semiconductor chip , 22-insulating film, 23-lower molybdenum sheet, 24-aluminum sheet, 25-the lower surface of DC positive copper bar or AC output copper bar, 26-DC negative copper bar or the upper surface of AC output copper bar, 27-positioning groove.

Detailed ways

In order to better understand the present invention, the technical solutions of the present invention will be described clearly and in detail below with reference to the accompanying drawings and specific embodiments.

In the description of the present invention, it should be noted that a series of terms describing the orientation, such as "upper", "lower", "left", "right", "inner", "outer", "vertical", " "Horizontal" and the like all indicate the orientation or positional relationship based on the drawings, which are only for the convenience of the description of the present invention, rather than indicating or implying that the devices or components in the present invention must have a specific orientation or be performed in a specific orientation. construction or operation, and therefore should not be construed as limiting the invention.

As shown in FIG. 2, a schematic diagram of the structure of a specific embodiment of the highly integrated crimping packaged power module embedded in the fixture of the present invention is shown. The crimping packaged power module based on the present invention mainly includes double-sided crimping Semiconductor chip units of molybdenum and aluminum sheets, DC conductive copper bars and AC conductive copper bars with a laminated structure, aluminum heat sinks with fins, high-strength insulating double-headed screws, and insulating films, of which the double-headed screws are made of Made of polyetheretherketone, insulating film made of polyethylene terephthalate.

Specifically, the DC conductive copper bar includes a DC positive copper bar 11 and a DC negative copper bar 17, and the AC conductive copper bar serves as the AC output copper bar 15; the two sides of the AC output copper bar 15 are symmetrically installed with semiconductor chip units 14, The periphery of the semiconductor chip unit 14 is evenly distributed with threaded holes penetrating the DC positive copper bar 11 , the AC output copper bar 15 and the DC negative copper bar 17 , which are fastened by the insulating double-headed screws 12 , and the external threads on the insulating double-headed screws 12 It is engaged with the internal thread of the threaded hole to generate a crimping force; the upper and lower surfaces of the DC positive copper bar 11 and the DC negative copper bar 17 are provided with insulating films, and the DC positive copper bar 11 and the DC negative copper bar 17 are provided with DC bus capacitors Interface, the AC output copper bar 15 is provided with a load interface.

The structure of a clip-embedded high-integration pressure-contact package power module in a preferred implementation of the present invention and a manufacturing method are given below.

Drill straight through holes in the middle of the DC positive copper bar 11, the DC negative copper bar 17 and the AC output copper bar 15, and pull out the right-hand thread with the same pitch on the DC positive copper bar 11 and the DC negative copper bar 17, and make each hole The positions are aligned and the diameters are the same. A square positioning groove is excavated on the DC positive copper bar 11, the AC output copper bar 15, and the DC negative copper bar 17, wherein the AC output copper bar 15 is excavated with square positioning grooves on both sides and the positions are corresponding, and the DC positive copper bar 11 is under The length and width of the grooves on the surface and the lower surface of the AC output copper bar 15 are kept consistent with the positive surface of the semiconductor chip unit 14, and the length and width of the grooves on the upper surface of the DC negative copper bar 17 and the upper surface of the AC output copper bar 15 are kept consistent with the semiconductor chip unit 14. The surfaces of the negative electrodes of the chip unit 14 are consistent, and the positive and negative electrodes of the semiconductor chip unit 14 are closely attached to the grooves.

Through holes are punched in the upper insulating film 10 of the DC positive copper bar, the lower insulating film 13 of the DC positive copper bar, the upper insulating film 16 of the DC negative copper bar, and the lower insulating film 18 of the DC negative copper bar. , the AC output copper bar 15 and the DC negative copper bar 17 are all aligned and of the same size. Straight through square holes are dug in the lower insulating film 13 of the DC positive copper bar and the upper insulating film 16 of the DC negative copper bar, the size of which is the same as that of each semiconductor chip unit 14 . The straight-through square holes on the insulating film are aligned with the square positioning grooves on the copper bars, and the semiconductor chip units 14 are positioned and fastened together.

The upper insulating film 10 of the DC positive copper bar, the DC positive copper bar 11, the lower insulating film 13 of the DC positive copper bar, the semiconductor chip unit 14, the AC output copper bar 15, the DC negative copper bar upper insulating film 16, the DC negative copper bar 17 . The insulating film 18 of the lower layer of the DC negative copper bar is aligned vertically from top to bottom, and the semiconductor chip unit 14 is placed in the square positioning groove and fixed through the groove and the straight through square hole on the insulating film.

Set the pitch of the double-ended screw 12 to the pitch in the DC positive copper bar 11 and the DC positive and negative copper bar 17, so that the thread length at both ends of the double-ended screw is consistent with the thickness of the two DC copper bars, and the height of the insulated double-ended screw 12 is the same as The upper surface of the DC positive copper bar 11 and the lower surface of the AC output copper bar 15 are flush. Insert the insulating double-headed screw 12 into the copper bar and the through hole that has been drilled on the insulating film, fix it and apply the same torque to tighten the screw right-hand, convert the rotational torque into crimping force, and drive the copper bar to crimp the semiconductor chip unit. 14.

The positive heat sink 8 and the negative heat sink 19 are respectively attached to the surface of the upper insulating film 10 of the DC positive copper bar and the surface of the lower insulating film 18 of the DC negative copper bar. The elongated insulating double-headed screws 9 are embedded in the straight-through threaded holes made by the heat sink, copper bar, and insulating film. Without applying torque, the heat sink can be directly fixed and integrated, forming a high-integration crimp as shown in Figure 3. packaged power modules.

In this embodiment, a cross-sectional view of the pressed semiconductor chip unit 14 and the positioning groove is shown in FIG. 4 . Including: upper molybdenum sheet 20, semiconductor chip 21, insulating film 22, lower molybdenum sheet 23, aluminum sheet 24, lower surface 25 of DC positive copper bar 11 or AC output copper bar 15, DC negative copper bar 17 or AC output copper bar The upper surface 26 of the row 15 and the positioning groove 27 located between the DC copper row and the AC copper row.

The size of the upper molybdenum sheet 20 is consistent with the conductive size of the positive electrode of the semiconductor chip 21, the size of the lower molybdenum sheet is consistent with the conductive size of the negative electrode of the semiconductor chip 21, and the size of the aluminum sheet is consistent with the size of the lower molybdenum sheet. The conductive dimension is larger than that of the negative electrode of the semiconductor chip 21 , so a stepped limiting structure is provided at the negative electrode of the semiconductor chip 21 of the semiconductor chip unit 14 , which is wider at the top and narrower at the bottom. The pressed semiconductor chip unit 14 is placed in the positioning groove 27 as a whole. The lower insulating film of the DC positive copper bar and the upper insulating film of the DC negative copper bar are provided with stepped holes for the semiconductor chip unit 14 to pass through. The limit structure is matched, and the positioning groove and the insulating film play a positioning role at the same time. In order to match the structure of the semiconductor chip unit 14 , the positioning grooves 27 include large grooves provided on the lower surface 25 of the copper bars and small grooves provided on the upper surface 26 of the copper bars.

The positive electrode of the semiconductor chip 21 is connected to the upper molybdenum sheet 20 , the negative electrode is connected to the lower molybdenum sheet 23 , and the aluminum sheet 24 is located between the lower molybdenum sheet 23 and the positioning groove 27 . The thermal expansion coefficient of the upper molybdenum sheet 20 is between the copper bar and the semiconductor chip 21, and the deformation caused by heating is between the positioning groove 27 and the semiconductor chip 21, which can play a buffering role. The lower molybdenum sheet 23 and the aluminum sheet 24 are sequentially placed between the semiconductor chip 21 and the copper bar from top to bottom, the lower molybdenum sheet 23 can buffer the deformation of the positioning groove 27 and the semiconductor chip 21 when heated, and the aluminum sheet 24 buffers the upper molybdenum The residual stress of the sheet 20, the semiconductor chip 21, the lower molybdenum sheet 23 as a whole and the small groove. Specifically, the thickness of the upper molybdenum sheet 20 and the lower molybdenum sheet 23 is 100 μm˜400 μm, and the thickness of the aluminum sheet is 50 μm˜200 μm. The insulating film 22 is divided into two layers, and each layer has the same thickness, which plays an electrical insulating role while fixing the semiconductor chip unit 14 and prevents short circuit between two adjacent copper bars. Specifically, each layer of the insulating film has a thickness of more than 50 μm.

In another embodiment of the present invention, the upper and lower surfaces of the AC output copper bar 15 are symmetrically provided with a positioning groove 1 and a positioning groove 2 for mounting the semiconductor chip unit 14; the width of the semiconductor chip unit 14 is uniform, The positive electrode is tightly attached to the positioning groove 2, and the negative electrode is closely attached to the positioning groove 1; The positioning of the semiconductor chip unit 14 can be completed only by the AC output copper bar, and the height of the semiconductor chip unit 14 is slightly higher than the groove depths of the first and second positioning grooves. The semiconductor chip unit 14 is an integrated laminate assembly formed from top to bottom by an upper molybdenum sheet, a semiconductor chip, a lower molybdenum sheet and an aluminum sheet with the same dimensions except for thickness; the positive electrode of the semiconductor chip and the upper molybdenum sheet Press contact, the negative electrode is press contact with the lower molybdenum sheet, and the semiconductor chip adopts silicon diode chip, Schottky diode chip, silicon carbide diode chip or silicon carbide diode chip.

Compared with the prior art, as shown in FIG. 1 , the present invention is a typical crimping force realization clamp structure applied in an existing commercial crimping module, including a fastening bolt 1 , a supporting plate 2 , a fastening Stud 3, disc spring group 4, bearing plate 5, radiator 6, crimping module 7 and other parts. The disc spring group 4 is formed by stacking several identical disc springs to meet the crimping force required by the crimping module 7 . Fastening studs 1 are placed vertically at the four corners outside the crimping module 7, and the deformation of the disc spring group 4 is fixed through the support plate 2 and the fastening studs 3, so that the disc spring group 4 is kept in a compressed state and maintained crimp force.

To sum up, compared with the traditional crimping type power module, the crimping package power module of the present invention does not need to adopt the bonding wire process and welding process. Sheets and other metal sheets are used to achieve electrical connection, avoiding the failure problem caused by the easy falling off of the bonding wire and the easy wear of the solder layer; no need to use external fixtures, eliminating the need for large-volume fasteners, load-bearing plates, etc., saving costs and modules. Weight; using a specific embedded fixture structure, maintaining the crimping force while saving the fixture space, and making the pressed semiconductor chip bear even pressure; using a specific integrated structure of copper bars and heat sinks, effectively reducing stray inductance and thermal impedance , to achieve a power module with high integration characteristics.

The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications to the above-described embodiments can be readily made, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above-mentioned embodiments, and improvements and modifications made by those skilled in the art according to the disclosure of the present invention should all fall within the protection scope of the present invention.

Claims (10)

1. A high-integration crimping type encapsulation power module embedded in a fixture, characterized in that it comprises a positive heat sink (8), a press-fit module and a negative heat sink (19) that are sequentially connected from top to bottom; The crimping type module comprises a DC positive copper bar (11), an AC output copper bar (15), a DC negative copper bar (17) and a semiconductor chip unit (14); Semiconductor chip units (14) are symmetrically mounted on both sides of the AC output copper bar (15), and the periphery of the semiconductor chip unit (14) is evenly distributed with a DC positive copper bar (11) and an AC output copper bar (15) and the threaded hole of the DC negative copper bar (17), which is fastened by the insulating double-ended screw (12), and the crimping force is generated by the engagement of the external thread on the insulating double-ended screw (12) with the internal thread of the threaded hole; the DC positive electrode The upper and lower surfaces of the copper bar (11) and the DC negative copper bar (17) are provided with insulating films, the DC positive copper bar (11) and the DC negative copper bar (17) are provided with a DC bus capacitor interface, and the AC output copper bar ( 15) There is a load interface on it. 2. A clamp-embedded high-integration crimping package power module according to claim 1, wherein the upper and lower surfaces of the AC output copper bars (15) are symmetrically provided with semiconductor chip units Installed positioning groove 1 and positioning groove 2, the positive electrode of the semiconductor chip unit is closely attached to the positioning groove 2, and the negative electrode is closely attached to the positioning groove 1; The upper insulating film (16) is provided with through holes through which the semiconductor chip units (14) pass. 3. A clamp-embedded high-integration crimping package power module according to claim 1, wherein the height of the insulating double-ended screw (12) is the same as the DC positive copper bar (11) and the lower surface of the AC output copper bar (15) are flush. 4. A clamp-embedded high-integration crimping package power module according to claim 1, characterized in that, the semiconductor chip unit (14) is composed of an upper molybdenum sheet (20), a semiconductor chip ( 21), an integrated laminate assembly formed from top to bottom by a lower molybdenum sheet (23) and an aluminum sheet (24); the positive electrode of the semiconductor chip (21) is in crimp contact with the upper molybdenum sheet (20), and the negative electrode is in contact with the lower molybdenum sheet (20). The molybdenum sheet (23) is in crimp contact. 5 . The clamp-embedded high-integration crimping package power module according to claim 4 , wherein the thickness of the upper molybdenum sheet and the lower molybdenum sheet is 100 μm to 400 μm, and the thickness of the aluminum sheet is 100 μm to 400 μm. 6 . 50μm～200μm. 6. A clamp-embedded high-integration press-fit packaged power module according to claim 4, wherein the semiconductor chip is a silicon diode chip, a Schottky diode chip, a silicon carbide diode chip or a Silicon carbide diode chips. 7. A clamp-embedded high-integration crimping packaged power module as claimed in claim 1, wherein the semiconductor chip unit is provided with a stepped limit structure, the lower insulating film of the DC positive copper bar and the The upper insulating film of the DC negative copper bar is provided with a stepped hole for the semiconductor chip unit to pass through, and the stepped hole is matched with the stepped limiting structure. 8. A clamp-embedded high-integration crimping package power module according to claim 1, wherein the insulating double-headed screw (12) is made of polyetheretherketone, and the insulating film Made of polyethylene terephthalate. 9 . The clamp-embedded high-integration crimping package power module according to claim 1 , wherein the thickness of each insulating film is more than 50 μm. 10 . 10. A clamp-embedded high-integration crimp-type packaged power module according to claim 1, characterized in that the positive heat sink (8), the crimp module and the negative heat sink (19) ) is provided with a through threaded hole, which is fastened by an extended insulated double-headed screw.

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