CN116213860A - Solder paste screen printing pattern and vacuum reflow soldering method - Google Patents
Solder paste screen printing pattern and vacuum reflow soldering method Download PDFInfo
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- CN116213860A CN116213860A CN202211720497.5A CN202211720497A CN116213860A CN 116213860 A CN116213860 A CN 116213860A CN 202211720497 A CN202211720497 A CN 202211720497A CN 116213860 A CN116213860 A CN 116213860A
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- Prior art keywords
- solder paste
- reflow soldering
- screen printing
- vacuum reflow
- rectangle
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
- H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
- H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
- H05K3/341—Surface mounted components
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K1/00—Soldering, e.g. brazing, or unsoldering
- B23K1/0008—Soldering, e.g. brazing, or unsoldering specially adapted for particular articles or work
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
- B41C1/00—Forme preparation
- B41C1/14—Forme preparation for stencil-printing or silk-screen printing
- B41C1/145—Forme preparation for stencil-printing or silk-screen printing by perforation using an energetic radiation beam, e.g. a laser
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Optics & Photonics (AREA)
- Toxicology (AREA)
- Electric Connection Of Electric Components To Printed Circuits (AREA)
Abstract
The invention discloses a solder paste screen printing pattern and a vacuum reflow soldering method, wherein the screen printing pattern is arranged in the middle of a heat dissipation copper plate, the overall shape of the screen printing pattern is rectangular, the rectangle is divided into a plurality of identical units, each unit consists of a plurality of pentagons and a plurality of rectangular small blocks, and bubble escape channels are reserved among the adjacent pentagons, pentagons and the rectangular small blocks and among the rectangular small blocks, and are used for adopting vacuum reflow soldering, so that bubbles can escape quickly, and the soldering void ratio is reduced; a vacuum reflow soldering process is also provided for the screen printed pattern. According to the invention, the problem that holes are easy to form by adopting solder paste for welding is solved through a screen printing pattern with reasonable design, one-time welding of a chip, a ceramic copper-clad substrate and a heat-dissipating copper plate is realized, and the production efficiency is improved.
Description
Technical Field
The invention belongs to the technical field of IGBT welding, and particularly relates to a solder paste screen printing pattern and a vacuum reflow welding method.
Background
As is well known, IGBT (Insulated Gate Bipolar Transistor), an insulated gate bipolar transistor is a composite fully-controlled voltage-driven power semiconductor device composed of a bipolar triode and an insulated gate field effect transistor, and has the advantages of high input impedance of the metal oxide semiconductor field effect transistor and low conduction voltage drop of the power transistor. The IGBT combines the advantages of the two devices and has the performance characteristics of high frequency, high voltage, large current and easy on and off. Therefore, the device is widely applied to the fields of locomotive traction, industrial control, wind power generation, automobile power and the like, and is particularly applied to equipment such as alternating current motors, frequency converters, switching power supplies, lighting circuits, traction transmission and the like.
In recent years, with the development of microelectronic technology, the greater the density of power devices, the more stringent the requirements for assembly soldering. Reducing the welding void is a core problem of high-power device assembly. When the solder paste is used for welding the large bonding pad, the cavity is generated mainly because a large amount of organic solvents are contained in the solder paste, and the solvents are gradually volatilized in the brazing heating process to generate a large amount of gas, so that the cavity is finally formed after the solder paste is sealed in the bonding pad, and heat dissipation is affected. The core structure of the medium-low voltage welding type IGBT device is a chip, a welding layer, a ceramic copper-clad substrate, a welding layer and a heat dissipation copper plate, wherein the welding layer mainly comprises two parts: firstly, a welding layer between a chip and a ceramic copper-clad substrate; and secondly, a welding layer between the ceramic copper-clad substrate and the heat-dissipating copper plate. Prior art welding is typically done in two passes: welding for the first time: the chip 1 and the ceramic copper-clad substrate 3 are welded by using solder paste 2 to form a subunit, as shown in fig. 1; and (3) welding for the second time: the subunit and the heat-dissipating copper plate 4 are welded by a soldering lug 5 to form a complete heat-dissipating channel from the chip to the copper plate. The welding in the prior art is completed in two times, the process is complex, the production efficiency is low, and the welding is not suitable for large-scale production.
In order to improve the production efficiency and reduce the process complexity, solder paste is used for welding, and a one-time welding process of a chip, a ceramic copper-clad substrate and a heat-dissipating copper plate is adopted. The area of the ceramic copper-clad substrate is far larger than the area of the chip, so that a printed pattern with reasonable design and a vacuum reflow soldering process aiming at the pattern are easy for bubbles to escape, and the reduction of welding layer cavities becomes a key.
In view of the above, the present inventors have proposed a solder paste screen printing pattern and a vacuum reflow soldering method to solve the above-mentioned problems.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a solder paste screen printing pattern and vacuum reflow soldering method. However, because the ceramic copper-clad substrate has large area and is easy to form a cavity by adopting solder paste for welding, the invention also designs a reasonable printed pattern, reduces the cavity rate of a welding layer and ensures the welding quality.
The invention aims at solving the problems by the following technical scheme:
the utility model provides a soldering tin cream screen printing figure, screen printing figure sets up in the middle part of heat dissipation copper, screen printing figure overall shape is rectangle, the rectangle is divided into the same unit of a plurality of, every the unit comprises a plurality of pentagons and a plurality of rectangle fritter, and all reserve bubble escape canal between the adjacent pentagon, between pentagon and the rectangle fritter and between the rectangle fritter for adopt vacuum reflow soldering, make things convenient for the bubble to escape fast, reduce the welding void ratio.
Further, the rectangular outline of the screen printed pattern is formed by adding a laser etching groove on the heat dissipation copper plate, and is used for preventing solder from overflowing.
Further, the rectangle is wholly divided into three identical units, and pentagons and rectangles on each unit are distributed in a central symmetry mode.
Further, the size of the lower copper layer of the ceramic copper-clad substrate is 38mm multiplied by 31.5mm, and the size of the heat dissipation copper plate is 122mm multiplied by 62mm.
A vacuum reflow soldering method for screen printing patterns of solder paste, the vacuum reflow soldering method comprising the following specific steps:
step one, a preheating section: quick vacuumizing, filling N2H2, filling N2, heating to a preset temperature, and preserving heat for 10-15 s;
step two, a reflux section: slowly vacuumizing, heating to a preset temperature, preserving heat for 5-10 s, slowly vacuumizing, wherein the pressure value of a cavity is 100-200 mbar, rapidly vacuumizing, the pressure value of the cavity is 1-3 mbar, and filling N 2 The cavity pressure value is 950mbar;
step three, a cooling section: cooling is carried out twice.
Further, the temperature after the temperature rise in the first step is 15-20 ℃ lower than the melting point of the solder paste.
Further, the temperature after the temperature rise in the second step is 30-40 ℃ higher than the melting point of the solder paste.
Further, in the third step: cooling to 70-100 ℃ for the first time, and keeping for 5-10 s; and cooling to 45 ℃ for the second time, and keeping for 60-100 s.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a screen printing pattern suitable for large-area solder paste welding and a vacuum reflow welding method aiming at the printing pattern. Compared with the traditional two-time welding, the production efficiency is greatly improved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate principles of the invention and together with the description, serve to explain the principles of the invention.
In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, and it will be obvious to a person skilled in the art that other drawings can be obtained from these drawings without inventive effort.
FIG. 1 is a schematic diagram of a prior art chip and ceramic copper-clad substrate soldered;
FIG. 2 is a schematic diagram of a prior art subunit and copper plate weld;
FIG. 3 is a view showing the external shape of a heat dissipating copper plate according to an embodiment of the present invention;
FIG. 4 is a screen printed pattern of solder paste according to the present invention;
wherein: 1 is a chip; 2 is solder paste; 3 is a ceramic copper-clad substrate; 4 is a heat dissipation copper plate; 5 is a soldering lug; and 6 is a laser etched groove.
Detailed Description
Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the invention. Rather, they are merely examples of devices that are consistent with aspects of the invention that are set forth in the following claims.
The present invention will be described in further detail below with reference to the drawings and examples for better understanding of the technical solutions of the present invention to those skilled in the art.
The invention aims to improve the production efficiency, so that solder paste welding is uniformly adopted to realize one-time welding of chips, ceramic copper-clad substrates and heat-dissipating copper plates. However, since the ceramic copper-clad substrate has a large area and is easy to form voids by solder paste welding, a reasonable design of printed patterns is required, and the void rate of a solder layer is reduced. The following screen printing patterns are designed for this design in combination with the actual design.
Referring to fig. 3 to 4, the invention provides a solder paste screen printing pattern, which is arranged in the middle of a heat dissipation copper plate, wherein, as shown in fig. 3, the size of a copper layer under a ceramic copper-clad substrate is 38mm multiplied by 31.5mm, the size of the heat dissipation copper plate is 122mm multiplied by 62mm, and the rectangular outline of the screen printing pattern is formed by adding a laser etching groove 6 on the heat dissipation copper plate, so as to prevent solder from overflowing. The screen printing pattern is particularly shown in fig. 4, the whole screen printing pattern is rectangular, the rectangle is divided into a plurality of identical units, each unit consists of a plurality of pentagons and a plurality of rectangle small blocks, and bubble escape channels are reserved among the adjacent pentagons, pentagons and rectangle small blocks and among the rectangle small blocks and are used for adopting vacuum reflow soldering, so that bubbles can escape quickly, and the welding void ratio is reduced.
Preferably, the rectangle of the invention is integrally divided into three identical units, and pentagons and rectangles on each unit are distributed in a central symmetry manner.
In another aspect, the present invention provides a method of vacuum reflow soldering of solder paste screen printed graphics, the method comprising the steps of:
step one, a preheating section: quick vacuum pumping-N filling 2 H 2 N-charging 2 The temperature after heating is 15-20 ℃ lower than the melting point of the solder paste, and the temperature is kept for 10-15 s;
step two, a reflux section: slowly vacuumizing, heating to a temperature 30-40 ℃ higher than the melting point of the solder paste, preserving heat for 5-10 s, slowly vacuumizing, wherein the pressure value of the cavity is 100-200 mbar, the pressure value of the fast vacuumizing cavity is 1-3 mbar, and filling N 2 The cavity pressure value is 950mbar;
step three, a cooling section: cooling for two times, wherein the temperature is reduced to 70-100 ℃ for the first time, and the temperature is kept for 5-10 s; and cooling to 45 ℃ for the second time, and keeping for 60-100 s.
The foregoing is only a specific embodiment of the invention to enable those skilled in the art to understand or practice the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention.
It will be understood that the invention is not limited to what has been described above and that various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.
Claims (8)
1. The utility model provides a soldering tin cream screen printing figure, its characterized in that, screen printing figure sets up in the middle part of heat dissipation copper, screen printing figure overall shape is rectangle, the rectangle is divided into a plurality of same unit, every the unit comprises a plurality of pentagons and a plurality of rectangle fritter, and all reserve bubble escape canal between the adjacent pentagon, between pentagon and the rectangle fritter and between the rectangle fritter for adopt vacuum reflow soldering, make things convenient for the bubble to escape fast, reduce the welding void ratio.
2. A solder paste screen printed pattern according to claim 1, wherein the rectangular outer contour of the screen printed pattern is formed by adding laser etched grooves to a heat dissipating copper plate for preventing solder from overflowing.
3. A solder paste screen printed pattern according to claim 1, wherein the rectangle is wholly divided into three identical units, and pentagons and rectangles on each unit are arranged in central symmetry.
4. A solder paste screen printed pattern according to claim 1, wherein the lower copper layer of the ceramic copper clad substrate has dimensions 38mm x 31.5mm and the heat sink copper plate has dimensions 122mm x 62mm.
5. A method of vacuum reflow soldering of solder paste screen printed graphics according to claims 1 to 4, characterised in that the method of vacuum reflow soldering comprises the following specific steps:
step one, a preheating section: quick vacuum pumping-N filling 2 H 2 N-charging 2 Heating to a preset temperature, and preserving heat for 10-15 s;
step two, a reflux section: slowly vacuumizing, heating to a preset temperature, preserving heat for 5-10 s, slowly vacuumizing, wherein the pressure value of a cavity is 100-200 mbar, rapidly vacuumizing, the pressure value of the cavity is 1-3 mbar, and filling N 2 The cavity pressure value is 950mbar;
step three, a cooling section: cooling is carried out twice.
6. The method of vacuum reflow soldering of solder paste screen printed patterns according to claim 5, wherein the temperature after the step one is raised is 15 ℃ to 20 ℃ lower than the melting point of the solder paste.
7. The method for vacuum reflow soldering of solder paste screen printed patterns according to claim 5, wherein the temperature after the second heating is 30-40 ℃ higher than the melting point of the solder paste.
8. The method for vacuum reflow soldering of solder paste screen printed patterns in accordance with claim 5, wherein in step three: cooling to 70-100 ℃ for the first time, and keeping for 5-10 s; and cooling to 45 ℃ for the second time, and keeping for 60-100 s.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211720497.5A CN116213860A (en) | 2022-12-30 | 2022-12-30 | Solder paste screen printing pattern and vacuum reflow soldering method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211720497.5A CN116213860A (en) | 2022-12-30 | 2022-12-30 | Solder paste screen printing pattern and vacuum reflow soldering method |
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| Publication Number | Publication Date |
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| CN116213860A true CN116213860A (en) | 2023-06-06 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202211720497.5A Pending CN116213860A (en) | 2022-12-30 | 2022-12-30 | Solder paste screen printing pattern and vacuum reflow soldering method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117497426A (en) * | 2023-12-29 | 2024-02-02 | 广东巨风半导体有限公司 | Packaging method of power module |
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- 2022-12-30 CN CN202211720497.5A patent/CN116213860A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117497426A (en) * | 2023-12-29 | 2024-02-02 | 广东巨风半导体有限公司 | Packaging method of power module |
| CN117497426B (en) * | 2023-12-29 | 2024-03-26 | 广东巨风半导体有限公司 | Packaging method of power module |
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