CN115008060A - Tin-based composite material preformed soldering lug for power chip packaging and preparation method thereof - Google Patents
Tin-based composite material preformed soldering lug for power chip packaging and preparation method thereof Download PDFInfo
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- CN115008060A CN115008060A CN202210608485.7A CN202210608485A CN115008060A CN 115008060 A CN115008060 A CN 115008060A CN 202210608485 A CN202210608485 A CN 202210608485A CN 115008060 A CN115008060 A CN 115008060A
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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
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/26—Selection of soldering or welding materials proper with the principal constituent melting at less than 400 degrees C
- B23K35/262—Sn as the principal constituent
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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
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/40—Making wire or rods for soldering or welding
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Abstract
The embodiment of the invention discloses a tin-based composite material preformed soldering lug for packaging a power chip and a preparation method thereof. The tin-based composite material preformed soldering lug consists of lead-free high-tin soft solder and a high-temperature reinforcing phase. Wherein the lead-free high-tin soft solder is an alloy with tin content higher than 90%; the high-temperature reinforcing phase is a metal capable of reacting with tin to generate a high-melting point intermetallic compound and comprises copper, nickel, silver, copper-nickel alloy and the like, and the form of the high-temperature reinforcing phase can be one or more of granular, filiform, net-shaped and sheet-shaped. The invention introduces high-temperature reinforcing phase into lead-free high-tin soft solder by accumulative pack rolling and uniformly distributes the high-temperature reinforcing phase. The preformed soldering lug can form all high-temperature phases in a chip packaging reflow soldering process, namely, a high-melting point intermetallic compound filling the whole soldering lug can be formed by short-time reflow at a low temperature, and then the high-temperature-resistant soldering lug for interconnecting the chip interfaces of the power device is obtained.
Description
Technical Field
The invention relates to a preformed soldering lug, in particular to a tin-based composite material preformed soldering lug for packaging a power chip and a preparation method thereof, belonging to the technical field of interconnection of electronic packaging materials and power device packaging chips.
Background
The power semiconductor device bears core functions of voltage transformation, frequency conversion and direct current and alternating current interchange in a power electronic system, and has wide application in a plurality of fields of domestic electric appliances, consumer electronics, new energy automobiles, rail transit, communication base stations, industrial control, power transmission and the like. In recent years, third-generation semiconductor materials are more and more widely applied to power devices, and the third-generation semiconductor materials such as silicon carbide and gallium nitride have the advantages of wider forbidden band, high breakdown electric field intensity, high electron migration rate and the like, so that the third-generation semiconductor materials can better meet the development requirements of power chips on high power, high frequency and high integration. However, the third generation semiconductor generates a large amount of heat during operation, the traditional lead-free solder with high tin content and low melting point cannot meet the use environment, and the corresponding high-temperature connecting material is quite lack.
Some high melting point gold-based alloy solders have been used for power device packaging, such as Au-20 Sn having a melting point of 280 c and Au-3 Si having a melting point of 363 c. However, they are not widely used due to the high material cost. Eutectic Zn-6 Al alloys with a melting point of 380 c may be candidate materials, but are prone to oxidation and corrosion. In addition, the high melting point of the solders and the necessary high temperature process result in increased requirements for soldering equipment, and thus these solders are not widely used for power device packaging. At present, because no suitable high-melting-point lead-free solder is available as a substitute, power device packaging still largely adopts environmentally-friendly high-lead-content solder. In order to fully utilize the excellent performance of the power device, the development of a power chip packaging connection material which is low in cost, green and environment-friendly and can be used for power device interconnection at relatively low temperature, and the joint of the power chip packaging connection material can work at high temperature efficiently is urgently needed.
The transient liquid phase connection technology is characterized in that the temperature is between the melting point of a low-melting-point phase and the melting point of a high-melting-point phase, a liquid low-melting-point phase (such as tin and indium) and a solid high-melting-point phase (such as copper, silver, nickel and the like) are subjected to metallurgical reaction, and isothermal solidification is carried out to generate a high-melting-point intermetallic compound. Therefore, the high temperature resistant solder joint can be prepared by reflowing at low temperature using the transient liquid phase bonding technique. However, conventional transient liquid phase joining techniques have a significant disadvantage in that the reflux time required to consume all of the low melting phase is long, which greatly limits production efficiency. Therefore, the development of the lead-free solder which can be rapidly reflowed at low temperature and the solder joint of which can be stably served at high temperature is of great significance.
The chinese invention patent CN104625466B discloses a tin-based/copper particle composite solder capable of quickly forming high-temperature solder joints at low temperature, wherein the composite solder is a composite tin paste composed of tin-based solder powder, copper particle powder and paste soldering flux. Because the tin-based solder and the high melting point copper are both powdery, the contact area of tin and copper is increased, and the reflow time is effectively shortened by using the tin paste to prepare the joint through transient liquid phase connection. However, since the composite solder is in the form of a paste, flux evaporation during reflow can cause a larger area of voids within the solder joint, which can reduce the reliability of the solder joint.
Chinese invention patent CN105290418A discloses a plating method for plating a weldable thick tin layer on the surface of a micro-nano copper ball, copper powder is chemically tinned to form Cu @ Sn core-shell structure bimetallic powder, and then the bimetallic powder is pressed into a preset sheet under the action of pressure. The highest melting point of the obtained welding spot reaches 676 ℃ after the preset sheet reflows at 250 ℃; and because the solder is in the form of a sheet, the problem of cavities caused by volatilization of the soldering flux is effectively avoided. However, the method of the invention needs a large amount of reagents, including a complexing agent, a reducing agent, a stabilizing agent, an antioxidant and the like, and is difficult to realize low-cost industrial production on the basis of the existing equipment.
Disclosure of Invention
Aiming at the technical problems, in order to solve the problems of complex preparation process and insufficient high temperature resistance in use of the existing lead-free tin-based solder for packaging the power device, the embodiment of the invention provides a tin-based composite material preformed soldering lug and a preparation method thereof. The tin-based composite material preformed soldering lug is simple in preparation process, low in equipment requirement and low in material cost, and can be used for preparing large-size strips, so that the tin-based composite material preformed soldering lug can be well matched with existing industrial equipment and is high in production efficiency.
The first aspect of the embodiment of the invention provides a tin-based composite material preformed soldering lug for packaging a power chip, which is characterized in that a high-temperature reinforcing phase is introduced through an accumulative roll-lamination process and uniformly dispersed into a lead-free high-tin soft solder to prepare the preformed soldering lug, and the tin-based composite material preformed soldering lug can form a high-melting point intermetallic compound filling the whole soldering point after being heated for a short time at a low temperature so as to obtain a high-temperature-resistant soldering point for interconnecting a power chip packaging interface;
the accumulative roll-lamination process is characterized in that a high-temperature reinforcing phase is coated between lead-free high-tin soft solders to form a sandwich structure or a multi-layer sandwich structure, and then the high-temperature reinforcing phase is uniformly dispersed in the lead-free high-tin soft solders and is completely compounded with the lead-free high-tin soft solders to form the composite material through a pressure processing method of repeated lamination rolling at a set temperature.
Optionally, the high temperature reinforcing phase is one or more of copper, nickel, silver, copper-nickel alloy or other metal capable of reacting with tin to form a high melting point intermetallic compound, and may be in the form of one or more of granules, filaments, nets and sheets, with a particle size of 0.1-20 microns, a filament length of 20-1000 microns, a filament or net diameter of 0.1-20 microns, and a sheet thickness of 0.1-20 microns.
Optionally, the lead-free high-tin solder is one or more of Sn-Cu alloy, Sn-Ag-Cu alloy or pure Sn which is widely used at present, and the tin mass fraction of the lead-free high-tin solder is higher than 90%, and the lead-free high-tin solder can be in a sheet shape, a block shape or other shapes which can be subjected to rolling and pressing.
Optionally, in the tin-based composite material preformed soldering lug, the mass ratio of the lead-free high-tin solder to the high-temperature reinforcing phase is 6: 1-1: 1. The mass ratio of the lead-free high-tin soft solder to the high-temperature reinforcing phase is 6: 1-1: 1, so that a certain amount of high-temperature-resistant intermetallic compounds can be generated in the solder joint after reflow, and the solder joint can be in service at high temperature; and poor rolling effect, such as cracking, caused by excessive reinforcing phases in the preformed soldering lug can be avoided. The proportion is high, the reinforcing phase is too little, and the amount of intermetallic compounds generated in the welding spot after reflow is too low to be interconnected into a three-dimensional skeleton network, so that the high-temperature resistance of the welding spot is deteriorated; at low ratios, too much of the relatively hard and brittle reinforcing phase can degrade the workability of the preformed solder fillet and even cause cracking of the material during the cumulative lap rolling.
The second aspect of the embodiments of the present invention provides a method for preparing a preformed solder tab of a tin-based composite material for packaging a power chip, including the following steps:
(1) preparing a substrate: smelting a lead-free high-tin soft solder alloy according to set alloy components, preparing a smelted cast ingot into a sheet-shaped prefabricated sheet with the thickness of 0.1-0.5 mm by a pressure processing method, and then annealing and softening the prefabricated sheet;
(2) introducing a high-temperature reinforcing phase: carrying out surface treatment on the prefabricated sheet, coating the high-temperature reinforcing phase on the surface of the prefabricated sheet, stacking to form a sandwich structure or a multi-layer sandwich structure, and fixing the periphery of the structure;
(3) pre-rolling and thinning: thinning the sandwich or multilayer sandwich structure to a prefabricated sheet with the thickness of 0.1-0.5 mm by a pressure processing method;
(4) accumulating and pack rolling: carrying out surface treatment on the prefabricated sheets, folding and stacking the prefabricated sheets, and carrying out one-time rolling on the folded prefabricated sheets to further disperse the high-temperature reinforcing phase; repeating the above method to complete the accumulative rolling of the multilayer prefabricated sheet;
(5) and (3) finish rolling: increasing the rolling reduction of the last pass to improve the bonding quality between the lead-free high-tin soft solder and the high-temperature enhanced phase interface, and enabling the thickness of the multilayer composite prefabricated sheet to be 0.05-0.4 mm;
(6) preforming: and flattening the unsmooth multilayer composite prefabricated sheet after final rolling, annealing, forming the annealed multilayer composite prefabricated sheet into a preformed sheet with a required shape in a blanking mode, and finally obtaining the tin-based composite material preformed soldering lug for packaging the power chip.
Optionally, in step (1), the pressure processing method includes, but is not limited to, rolling, extruding, drawing, and the like.
Optionally, in step (1), the pressure processing method comprises adding a metal melting covering agent.
Optionally, in the step (1), the annealing temperature is 90-110 ℃ and the annealing time is 1-2 hours.
In the step (1), the smelted cast ingot is prepared into a flaky prefabricated sheet with the thickness of 0.1-0.5 mm by a pressure processing method, the processing is difficult due to too low thickness, and the stress concentration of a welding spot in the service process is not easy to relieve; when the thickness is too thick, voids are easily generated during reflow, and the reliability of the welding spot is reduced.
Optionally, in the step (2), a specific method of surface-treating the preform sheet includes: the surface of the preform sheet was deaerated and roughened with a stainless steel brush.
In step (3) of the present invention, the pre-rolling reduction is performed to preliminarily fix the reinforcing phase, such as copper particles. If the pre-rolling thinning is not carried out, copper particles can splash out from the periphery of the preformed soldering lug under the action of rolling pressure during the next step of cumulative overlapping rolling.
Optionally, in the step (3), the press working method is a rolling method.
Optionally, in the step (4), a specific method of surface-treating the preform sheet includes: the surface of the preform sheet was deaerated and roughened with a stainless steel brush.
Optionally, in the step (4), the cumulative rolling temperature is 80-150 ℃, the reduction is 50%, and the cumulative rolling number is 3-8. The preformed soldering lug cannot be softened at a too low temperature, and the processing is difficult; when the temperature is too high, the material can stick to the roller of the rolling mill during rolling and even melt during rolling. The rolling times are less, and the effect of uniformly dispersing the reinforcing phase cannot be achieved; the preformed soldering lug is easy to crack and difficult to process due to excessive times.
Optionally, in the step (6), the annealing temperature is 90-110 ℃, and the annealing time is 1-2 h. The temperature is too low to soften the preformed soldering lug, so that the processability of the material is improved; when the temperature is too high, the material can stick to the roller of the rolling mill during rolling and even melt during rolling.
Compared with the existing high-temperature solder, the invention has the following advantages:
1. compared with the traditional high-lead solder and high-temperature lead-free alloy solder, the composite material preformed soldering lug can generate a high-temperature (not less than 415 ℃) resistant soldering point through short-time (3-10min) reflow at low temperature (232 plus 260 ℃), so that thermal shock and high residual stress caused by overhigh processing temperature are reduced, and the composite material preformed soldering lug can be well matched with traditional reflow soldering equipment.
2. Compared with other high-temperature composite solders, the composite preformed soldering lug is prepared by an accumulative roll-stacking technology, the preparation process is simple, and the requirement on equipment is not high; the raw materials mainly comprise tin, copper and nickel, so that the cost is low; in addition, the invention can prepare large-size strips which are prepared into various required shapes after being processed and blanked. Therefore, the invention has great potential for realizing low-cost industrial production of the high-temperature composite solder.
3. The invention can regulate and control the microstructure of the obtained welding spot by predesigned reinforced phase composition, content and combination form.
4. Under the condition of larger rolling reduction, the reinforcing phase is tightly combined with the solder matrix; the compact sheet form avoids the problem of cavities caused by the volatilization of the soldering flux of the cream solder for high temperature, thereby improving the reliability of the soldering point.
5. By controlling the thickness of the precast sheet processed in each step, the high-temperature reinforcing phase and the lead-free high-tin soft solder can be better compounded, and the high-temperature reinforcing phase can be uniformly distributed in the lead-free high-tin soft solder after the accumulative pack rolling.
6. The invention has low cost, simple process and high production efficiency, and can effectively solve the problems of complex process, no high temperature resistance and high cost of the existing connecting material for packaging the power chip.
Drawings
Fig. 1 is a Scanning Electron Microscope (SEM) image of a composite pre-formed solder bump prepared in example 1, wherein 1(b) is a partial enlarged view of 1(a), in which: 0101 is β -Sn, 0102 is Cu6Sn5 intermetallic compound, 0103 is copper microparticles.
Fig. 2 is a Scanning Electron Microscope (SEM) image of the composite pre-formed solder fillet prepared in example 2, wherein 2(b) is a partial enlarged view of 2(a), in which: 0201 is beta-Sn, 0202 is a Cu6Sn5 intermetallic compound, 0203 is a copper-nickel microparticle.
Fig. 3 is a Scanning Electron Microscope (SEM) image of the composite pre-formed solder bump prepared in example 3, wherein 3(b) is a partial enlarged view of 3(a), in which: 0301 is beta-Sn, 0302 is Cu6Sn5 intermetallic compound, 0303 is copper microparticle, and 0304 is copper mesh.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1: sn-6 Cu/30% Cu-MPs composite material preformed soldering lug and preparation process thereof
The composite material preformed soldering lug is formed by accumulating, overlaying and compounding Sn-6 Cu alloy (the mass fraction of tin is 94% and the mass fraction of copper is 6%) and copper micro particles (Cu-MPs for short), wherein the mass fraction of the Sn-6 Cu alloy in the composite material preformed soldering lug is 70%, and the mass fraction of the copper micro particles is 30%.
The preparation process of the composite material preformed soldering lug comprises the following steps:
(1) putting 10-20g of metal melting covering agent (the metal melting covering agent is a mixture of potassium chloride and lithium chloride, the mass ratio of the potassium chloride to the lithium chloride is 1.3:1) into an alumina crucible, heating to 500 ℃ by using a lead-free titanium tin furnace, putting 28.2g of tin block, adding 1.8g of copper sheet after the metal tin is completely melted, preserving heat for 30min, stirring once every 6-10min during heat preservation, pouring into a rectangular mold after heat preservation, and carrying out air cooling to obtain a rectangular Sn-6 Cu alloy ingot.
(2) And rolling the rectangular Sn-6 Cu alloy cast ingot into a prefabricated sheet by using a two-roll mill. Setting the rolling temperature to be 100 ℃, the rolling speed to be 3m/min, setting the initial roll gap distance to be 6mm, then shortening the roll gap distance of each pass by 0.5mm until the roll gap distance reaches 0.5mm, then sequentially adjusting the roll gap distances to be 0.25mm, 0.1mm and 0.05mm, and finally finely adjusting the roll gap distance to ensure that the thickness of the Sn-6 Cu prefabricated sheet is 0.1 mm.
(3) And smoothing the rolled wavy Sn-6 Cu prefabricated sheet by using an arc-shaped tool, and annealing the smoothed Sn-6 Cu prefabricated sheet at 100 ℃ for 1 h.
(4) 4 long Sn-6 Cu prefabricated sheets with the width and thickness of 30mm multiplied by 0.1mm are cut out, surface impurities are removed by polishing with a 2000-mesh stainless steel brush, and the Sn-6 Cu prefabricated sheets with the total weight of 5g are taken out and weighed as 4 pieces. Copper microparticles are uniformly printed on one surface of any 3 Sn-6 Cu prefabricated sheets through screen printing, and after printing is finished, 4 prefabricated sheets are mutually stacked, wherein copper powder is positioned among the prefabricated sheets to form a multi-layer sandwich structure, and the total weight is 7.14 g. And fixing four corners of the stacked strips in a stamping mode, setting the rolling temperature to be 100 ℃, the rolling speed to be 3m/min and the roll gap spacing to be 0.25mm, and carrying out first-pass rolling to obtain the prefabricated sheet.
(5) And polishing the composite prefabricated sheets by using a 2000-mesh stainless steel brush again to remove surface impurities, folding and stacking the composite prefabricated sheets from the middle, setting the rolling temperature to be 100 ℃, the rolling speed to be 3m/min and the roll gap interval to be 0.25mm, and rolling the folded and stacked composite prefabricated sheets by 50 percent of rolling reduction. And (5) circulating the steps for 5 times to finish the accumulative lap rolling of the multilayer composite prefabricated sheet.
(6) And (3) further shortening the roll gap distance to eliminate rolling springback, rolling the multilayer composite precast slab to the final thickness of 0.1mm, and then performing shape blanking to obtain a Sn-6 Cu/30% Cu-MPs composite material preformed soldering lug, wherein a Scanning Electron Microscope (SEM) picture is shown in figure 1, and it can be seen that the high-temperature reinforcing phase is uniformly distributed in the lead-free high-tin soft solder.
The Sn-6 Cu/30% Cu-MPs composite material preformed soldering lug of the embodiment can generate a soldering point with the temperature resistance of more than or equal to 415 ℃ after being reflowed for 5min at 255 ℃, so that thermal shock and high residual stress caused by overhigh processing temperature are reduced, and the soldering point can be well matched with the traditional reflow soldering equipment.
Example 2: sn-2.5 Cu/36% CuNi-MPs composite material preformed soldering lug and preparation process thereof
The composite material preformed soldering lug is formed by carrying out accumulative roll lamination on Sn-2.5 Cu alloy (the mass fraction of tin is 97.5 percent and the mass fraction of copper is 2.5 percent) and copper-nickel alloy micro particles (CuNi-MPs for short), wherein the mass fraction of Sn-2.5 Cu in the composite material preformed soldering lug is 64 percent, and the mass fraction of the copper-nickel alloy micro particles is 36 percent.
The preparation process of the composite material preformed soldering lug comprises the following steps:
(1) putting 10-20g of metal melting covering agent (the metal melting covering agent is a mixture of potassium chloride and lithium chloride, the mass ratio of the potassium chloride to the lithium chloride is 1.3:1) into an alumina crucible, heating to 500 ℃ by using a lead-free titanium tin furnace, putting 29.25g of tin block, adding 0.75g of copper sheet after the metal tin is completely melted, preserving heat for 30min, stirring once every 6-10min during heat preservation, pouring into a rectangular mold after heat preservation, and carrying out air cooling to obtain a rectangular Sn-2.5 Cu alloy ingot.
(2) The rectangular Sn-2.5 Cu alloy ingot is rolled into a prefabricated sheet by using a two-roll mill. Setting the rolling temperature to be 90 ℃ and the rolling speed to be 4.0m/min, setting the initial roll gap distance to be 6mm, then shortening the roll gap distance of each pass by 0.5mm until the roll gap distance reaches 0.5mm, then sequentially adjusting the roll gap distances to be 0.25mm, 0.1mm and 0.05mm, and finally finely adjusting the roll gap distance to ensure that the thickness of the Sn-2.5 Cu prefabricated sheet is 0.1 mm.
(3) And smoothing the rolled wavy Sn-2.5 Cu prefabricated sheet by using an arc-shaped tool, and annealing the smoothed Sn-2.5 Cu prefabricated sheet at 90 ℃ for 1 h.
(4) 4 long Sn-2.5 Cu prefabricated sheets with the width and thickness of 30mm multiplied by 0.1mm are cut out, surface impurities are removed by a 2000-mesh stainless steel brush, and the Sn-2.5 Cu prefabricated sheets with the total weight of 5g are taken out and weighed as 4 pieces. Uniformly printing copper-nickel alloy microparticles on one surface of any 3 Sn-2.5 Cu prefabricated sheets by screen printing, and stacking 4 prefabricated sheets after printing, wherein copper-nickel alloy powder is positioned among the prefabricated sheets to form a multilayer sandwich structure, and the total weight is 7.81 g. And fixing four corners of the stacked strips in a stamping mode, setting the rolling temperature to be 105 ℃, the rolling speed to be 2.5m/min and the roll gap spacing to be 0.25mm, and carrying out first-pass rolling to obtain the composite prefabricated sheet.
(5) Polishing the composite prefabricated sheet with a 2000-mesh stainless steel brush to remove surface impurities, folding and stacking the composite prefabricated sheet from the middle, setting the rolling temperature to be 105 ℃, the rolling speed to be 2.5m/min and the roll gap spacing to be 0.25mm, and rolling the folded and stacked composite prefabricated sheet at 50% of rolling reduction. And (5) circulating the steps for 6 times to finish the accumulative lap rolling of the multilayer composite prefabricated sheet.
(6) And (3) further shortening the roll gap distance to eliminate rolling springback, rolling the multilayer composite precast slab to obtain the final thickness of 0.1mm, and then performing shape blanking to obtain a Sn-2.5 Cu/36% CuNi-MPs composite material preformed soldering lug, wherein a Scanning Electron Microscope (SEM) picture is shown in figure 2, and as can be seen, the high-temperature reinforcing phase is uniformly distributed in the lead-free high-tin solder.
The Sn-2.5 Cu/36% CuNi-MPs composite material preformed soldering lug of the embodiment can generate a soldering point with the temperature resistance of more than or equal to 415 ℃ after 3min of reflow at 240 ℃, so that the thermal shock and high residual stress caused by overhigh processing temperature are reduced, and the soldering lug can be well matched with the traditional reflow soldering equipment.
Example 3: (Sn-8 Cu/24% Cu-MPs/5% Cu-mesh composite material preformed soldering lug and preparation process thereof
The composite material preformed soldering lug is formed by accumulating, laminating and compounding Sn-8 Cu alloy (the mass fraction of tin is 92% and the mass fraction of copper is 8%), copper micro particles (Cu-MPs for short) and a micro copper mesh (Cu-mesh for short), wherein the mass fraction of Sn-8 Cu in the composite material preformed soldering lug is 71%, the mass fraction of the copper micro particles is 24% and the mass fraction of the micro copper mesh is 5%.
The preparation process of the composite material preformed soldering lug comprises the following steps:
(1) putting 10-20g of metal melting covering agent (the metal melting covering agent is a mixture of potassium chloride and lithium chloride, the mass ratio of the potassium chloride to the lithium chloride is 1.3:1) into an alumina crucible, heating to 550 ℃ by using a lead-free titanium tin furnace, putting 27.6g of tin blocks, adding 2.4g of copper sheets after the metal tin is completely melted, preserving heat for 30min, stirring once every 6-10min during heat preservation, pouring the mixture into a rectangular mold after heat preservation, and carrying out air cooling to obtain a rectangular Sn-8 Cu alloy ingot.
(2) And rolling the rectangular Sn-8 Cu alloy cast ingot into a prefabricated sheet by using a two-roll mill. Setting the rolling temperature to be 110 ℃ and the rolling speed to be 2.0m/min, setting the initial roll gap distance to be 6mm, then shortening the roll gap distance of each pass by 0.5mm until the roll gap distance reaches 0.5mm, then sequentially adjusting the roll gap distances to be 0.25mm, 0.1mm and 0.05mm, and finally finely adjusting the roll gap distance to ensure that the thickness of the Sn-8 Cu prefabricated sheet is 0.1 mm.
(3) And smoothing the rolled wavy Sn-8 Cu prefabricated sheet by using an arc-shaped tool, and annealing the smoothed Sn-8 Cu prefabricated sheet at 110 ℃ for 1 h.
(4) 4 strips of Sn-8 Cu alloy sheets with the width and thickness of 35mm multiplied by 0.1mm are taken out by cutting, surface impurities are removed by a 2000-mesh stainless steel brush, and the strips are taken as 4 Sn-8 Cu prefabricated sheets with the total weight of 5 g. Copper microparticles are uniformly printed on one surface of any 3 Sn-8 Cu prefabricated sheets through screen printing, and after printing is finished, 4 prefabricated sheets are mutually stacked, wherein copper powder is positioned among the prefabricated sheets to form a multi-layer sandwich structure, and the total weight is weighed to be 6.69 g. And fixing four corners of the stacked strips in a stamping mode, setting the rolling temperature to be 100 ℃, the rolling speed to be 3m/min and the roll gap spacing to be 0.25mm, and carrying out first-pass rolling to obtain the composite prefabricated sheet.
(5) Polishing the composite prefabricated sheet with a 2000-mesh stainless steel brush to remove surface impurities, folding and stacking the composite prefabricated sheet from the middle, setting the rolling temperature at 100 ℃, the rolling speed at 3m/min and the roll gap spacing at 0.25mm, and rolling the folded and stacked composite prefabricated sheet at 50% reduction. And (5) circulating the steps for 3 times to finish the accumulative lap rolling of the multilayer composite prefabricated sheet.
(6) Further shortening the gap between the rolls for rolling to make the thickness of the multilayer composite precast slab be 0.1 mm.
(7) Removing impurities on the surface of the composite precast slab by using a 2000-mesh stainless steel brush, weighing 1 strip of a 250-mesh copper net with the total mass of 0.35g, and ultrasonically pickling by using 5% H2SO 4. The composite prefabricated sheet is folded into two parts with equal length and width, and the two parts are clamped with copper nets and then stacked to form a sandwich structure, wherein the copper nets are positioned inside, and four corners of a stacked strip are fixed in a stamping mode. Setting the rolling temperature to be 100 ℃, the rolling speed to be 3m/min and the roll gap spacing to be 0.1mm, and carrying out accumulative pack rolling for 2 times.
(8) Further shortening the gap distance to eliminate rolling springback, rolling the copper-containing net multi-layer composite precast sheet to a final thickness of 0.1mm, and shape-blanking to obtain
The Scanning Electron Microscope (SEM) picture of the Sn-8 Cu/24% Cu-MPs/5% Cu-mesh composite material preformed soldering lug is shown in figure 3, and it can be seen that the high-temperature reinforcing phase is uniformly distributed in the lead-free high-tin solder.
The Sn-8 Cu/24% Cu-MPs/5% Cu-mesh composite material preformed soldering lug can generate a solder joint with the temperature of 415 ℃ or higher after being reflowed at 255 ℃ for 5min, so that thermal shock and high residual stress caused by overhigh processing temperature are reduced, and the soldering lug can be well matched with traditional reflow soldering equipment.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A tin-based composite material pre-forming soldering lug for power chip packaging is characterized in that a high-temperature reinforcing phase is introduced through an accumulative roll-stacking process and uniformly dispersed into a lead-free high-tin soft solder to prepare a pre-forming soldering lug, and the tin-based composite material pre-forming soldering lug can form a high-melting point intermetallic compound for filling the whole soldering spot after being heated for a short time at a low temperature so as to obtain a high-temperature-resistant soldering spot for power chip packaging interface interconnection;
the accumulative roll-lamination process is to coat the high-temperature reinforcing phase between the lead-free high-tin soft solder to form a sandwich or multi-layer sandwich structure, and then to lead the high-temperature reinforcing phase to be uniformly dispersed in the lead-free high-tin soft solder and to be completely compounded with the lead-free high-tin soft solder to form the composite material through a pressure processing method of repeated lamination rolling at a set temperature.
2. The pre-formed solder tab of tin-based composite material for power chip package as claimed in claim 1, wherein the high temperature reinforcing phase is one or more of copper, nickel, silver, copper-nickel alloy or other metals that can react with tin to form high melting point intermetallic compounds;
further, the form of the high-temperature reinforcing phase is one or more of granular, filamentous, net-like and sheet-like;
further, the particle size of the high temperature reinforcing phase is 0.1-20 microns, the length of the wire is 20-1000 microns, the diameter of the wire or mesh is 0.1-20 microns, and the thickness of the sheet is 0.1-20 microns.
3. The solder preform of claim 1, wherein the solder is one or more of Sn-Cu alloy, Sn-Ag-Cu alloy, or pure Sn.
4. The preformed solder lug of tin-based composite material for packaging the power chip as claimed in claim 1, wherein the mass ratio of the lead-free high-tin soft solder to the high-temperature reinforcing phase in the preformed solder lug of tin-based composite material is 6: 1-1: 1.
5. The method for preparing the preformed solder lug of the tin-based composite material for packaging the power chip as recited in any one of claims 1 to 4, characterized by comprising the following steps:
(1) preparing a substrate: smelting a lead-free high-tin soft solder alloy according to set alloy components, preparing a smelted cast ingot into a sheet-shaped prefabricated sheet with the thickness of 0.1-0.5 mm by a pressure processing method, and then annealing and softening the prefabricated sheet;
(2) introducing a high-temperature reinforcing phase: carrying out surface treatment on the prefabricated sheet, coating the high-temperature reinforcing phase on the surface of the prefabricated sheet, stacking to form a sandwich structure or a multi-layer sandwich structure, and fixing the periphery of the structure;
(3) pre-rolling and thinning: thinning the sandwich or multilayer sandwich structure to a prefabricated sheet with the thickness of 0.1-0.5 mm by a pressure processing method;
(4) accumulating and pack rolling: carrying out surface treatment on the prefabricated sheets, folding and stacking the prefabricated sheets, and carrying out one-time rolling on the folded prefabricated sheets to further disperse the high-temperature reinforcing phase; repeating the above method to complete the accumulative rolling of the multilayer prefabricated sheet;
(5) and (3) finish rolling: increasing the rolling reduction of the last pass to improve the bonding quality between the lead-free high-tin soft solder and the high-temperature enhanced phase interface, and enabling the thickness of the multilayer composite prefabricated sheet to be 0.05-0.4 mm;
(6) preforming: and flattening the unsmooth multilayer composite prefabricated sheet after final rolling, annealing, forming the annealed multilayer composite prefabricated sheet into a preformed sheet with a required shape in a blanking mode, and finally obtaining the tin-based composite material preformed soldering lug for packaging the power chip.
6. The method for preparing the preformed solder lug of tin-based composite material for packaging the power chip as claimed in claim 5, wherein in the step (1), the pressure processing method comprises rolling, extruding or drawing;
the pressure processing method comprises the steps of adding a metal melting covering agent;
the annealing temperature is 90-110 ℃, and the annealing time is 1-2 hours.
7. The method for preparing the preformed solder lug of tin-based composite material for power chip packaging as claimed in claim 5, wherein in the step (2), the specific method for performing surface treatment on the prefabricated lug comprises the following steps: the surface of the preform sheet was deaerated and roughened with a stainless steel brush.
8. The method for preparing the preformed solder lug of tin-based composite material for packaging the power chip as claimed in claim 5, wherein in the step (3), the pressing method is a rolling method.
9. The method for preparing the preformed solder lug of tin-based composite material for power chip packaging as claimed in claim 5, wherein in the step (4), the specific method for performing surface treatment on the prefabricated lug comprises the following steps: deoxidizing and roughly manufacturing the surface of the prefabricated sheet by using a stainless steel brush;
the accumulative pack rolling temperature is 80-150 ℃, the reduction is 50%, and the accumulative pack rolling times are 3-8.
10. The method for preparing the preformed solder lug of the tin-based composite material for packaging the power chip as claimed in claim 5, wherein in the step (6), the annealing temperature is 90-110 ℃, and the annealing time is 1-2 h.
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| CN202210608485.7A CN115008060A (en) | 2022-05-31 | 2022-05-31 | Tin-based composite material preformed soldering lug for power chip packaging and preparation method thereof |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115846930A (en) * | 2022-12-29 | 2023-03-28 | 北京康普锡威科技有限公司 | Preformed solder composition, soldering lug and preparation method |
| CN116117380A (en) * | 2023-02-27 | 2023-05-16 | 山东建筑大学 | Zinc alloy soldering lug for copper-clad aluminum butt welding, preparation method and welding method |
| CN116352244A (en) * | 2023-04-12 | 2023-06-30 | 汕尾市栢林电子封装材料有限公司 | Preparation method for presetting gold-tin soldering lug by utilizing transient liquid phase diffusion soldering |
| CN116900545A (en) * | 2023-09-13 | 2023-10-20 | 北京理工大学 | Microalloyed laminated soldering lug for rapid transient liquid phase connection and preparation method thereof |
| CN116967658A (en) * | 2023-08-24 | 2023-10-31 | 广州汉源微电子封装材料有限公司 | Reinforced soldering lug and preparation method and application thereof |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002301588A (en) * | 2000-12-21 | 2002-10-15 | Hitachi Ltd | Solder foil, semiconductor device and electronic device |
| US20090236725A1 (en) * | 2006-04-28 | 2009-09-24 | Denso Corporation | Solder Preform and Electronic Component |
| TW201127541A (en) * | 2010-02-05 | 2011-08-16 | Univ Nat Pingtung Sci & Tech | Manufacturing method for lead-free solder material mixed with metal micro-particles |
| CN104625466A (en) * | 2015-01-21 | 2015-05-20 | 哈尔滨工业大学深圳研究生院 | Tin-radical welding flux/copper particle composite welding flux capable of forming high-temperature welding spots rapidly at low temperature |
| CN107486651A (en) * | 2017-08-02 | 2017-12-19 | 中国电器科学研究院有限公司 | A kind of preparation method of eutectic welding tablet |
| CN107695559A (en) * | 2017-10-18 | 2018-02-16 | 贵研铂业股份有限公司 | A kind of silver-based composite soldering foil and preparation method thereof |
| CN109967914A (en) * | 2017-12-27 | 2019-07-05 | 北京康普锡威科技有限公司 | A kind of tin copper high-temp leadless preformed solder of copper core structure used for electronic packaging |
| CN112440029A (en) * | 2020-11-20 | 2021-03-05 | 云南锡业集团（控股）有限责任公司研发中心 | Low-temperature composite solder alloy soldering lug and preparation method and use method thereof |
-
2022
- 2022-05-31 CN CN202210608485.7A patent/CN115008060A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002301588A (en) * | 2000-12-21 | 2002-10-15 | Hitachi Ltd | Solder foil, semiconductor device and electronic device |
| US20090236725A1 (en) * | 2006-04-28 | 2009-09-24 | Denso Corporation | Solder Preform and Electronic Component |
| TW201127541A (en) * | 2010-02-05 | 2011-08-16 | Univ Nat Pingtung Sci & Tech | Manufacturing method for lead-free solder material mixed with metal micro-particles |
| CN104625466A (en) * | 2015-01-21 | 2015-05-20 | 哈尔滨工业大学深圳研究生院 | Tin-radical welding flux/copper particle composite welding flux capable of forming high-temperature welding spots rapidly at low temperature |
| CN107486651A (en) * | 2017-08-02 | 2017-12-19 | 中国电器科学研究院有限公司 | A kind of preparation method of eutectic welding tablet |
| CN107695559A (en) * | 2017-10-18 | 2018-02-16 | 贵研铂业股份有限公司 | A kind of silver-based composite soldering foil and preparation method thereof |
| CN109967914A (en) * | 2017-12-27 | 2019-07-05 | 北京康普锡威科技有限公司 | A kind of tin copper high-temp leadless preformed solder of copper core structure used for electronic packaging |
| CN112440029A (en) * | 2020-11-20 | 2021-03-05 | 云南锡业集团（控股）有限责任公司研发中心 | Low-temperature composite solder alloy soldering lug and preparation method and use method thereof |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115846930A (en) * | 2022-12-29 | 2023-03-28 | 北京康普锡威科技有限公司 | Preformed solder composition, soldering lug and preparation method |
| CN116117380A (en) * | 2023-02-27 | 2023-05-16 | 山东建筑大学 | Zinc alloy soldering lug for copper-clad aluminum butt welding, preparation method and welding method |
| CN116352244A (en) * | 2023-04-12 | 2023-06-30 | 汕尾市栢林电子封装材料有限公司 | Preparation method for presetting gold-tin soldering lug by utilizing transient liquid phase diffusion soldering |
| CN116352244B (en) * | 2023-04-12 | 2024-05-24 | 汕尾市栢林电子封装材料有限公司 | Preparation method for presetting gold-tin soldering lug by utilizing transient liquid phase diffusion soldering |
| CN116967658A (en) * | 2023-08-24 | 2023-10-31 | 广州汉源微电子封装材料有限公司 | Reinforced soldering lug and preparation method and application thereof |
| CN116900545A (en) * | 2023-09-13 | 2023-10-20 | 北京理工大学 | Microalloyed laminated soldering lug for rapid transient liquid phase connection and preparation method thereof |
| CN116900545B (en) * | 2023-09-13 | 2023-12-08 | 北京理工大学 | Microalloyed laminated soldering lug for rapid transient liquid phase connection and preparation method thereof |
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