Silver-copper-titanium active soldering paste with high recovery coefficient as well as preparation method and application of silver-copper-titanium active soldering paste

Abstract

The invention relates to silver-copper-titanium active soldering paste with a high recovery coefficient and a preparation method and application of the silver-copper-titanium active soldering paste, and belongs to the technical field of heterogeneous material connection and semiconductor packaging. The silver-copper-titanium active soldering paste is composed of, by mass, 70%-90% of brazing filler metal powder and 10%-30% of scaling powder. The brazing filler metal powder is mixed powder composed of silver-copper-based powder, titanium-containing powder and other metal powder. The soldering flux is composed of, by mass, 40%-70% of a solvent, 20%-40% of rosin, 5%-20% of an active agent, 1%-15% of a thixotropic agent, 1%-10% of an interface modifier and 1%-10% of a corrosion inhibitor, and the thixotropic agent is composed of a short-range agent and a long-range agent according to the mass ratio of 1: (1-4). The recovery coefficient of the obtained soldering paste is close to 1, and the soldering paste has excellent printability, sagging resistance and storage stability and has wide application prospects in the fields of semiconductor packaging, power electronic devices, aerospace and the like.

Description

TECHNICAL FIELD

[0001] The application relates to a silver-copper-titanium active solder paste with a high recovery coefficient and a preparation method and application thereof, and belongs to the technical field of heterogeneous material connection and semiconductor packaging. BACKGROUND

[0002] In the fields of high-end equipment manufacturing such as power electronics and aerospace, reliable connection of ceramics and metals is of great significance. However, due to the significant differences in physical and chemical properties between ceramics and metals, conventional brazing filler metals are difficult to effectively wet the ceramic surface, and therefore active metal brazing technology is usually required. At present, Ag-Cu-Ti alloy, as the most widely used active brazing filler metal, can realize high-strength metallurgical bonding through the chemical reaction between titanium and ceramics. However, this type of brazing filler metal is currently mainly processed into foils and strips, which has the following limitations: first, the shape adaptability is poor, and it is difficult to be used for complex structures or small-sized workpieces, and assembly positioning is difficult; second, the component adjustability is low, and the preparation cost is high.

[0003] As an ideal alternative form, the solder paste can realize high-precision and automatic application through printing, spot coating and other processes, and significantly improve the production efficiency and process adaptability. However, the existing silver-copper-titanium active solder paste still has obvious deficiencies in the rheological properties, especially the poor thixotropy and the recovery coefficient far lower than 1, which leads to various process defects in actual application: first, the printing forming quality is poor, the viscosity recovery lags behind during high-speed printing, and the pattern distortion, bridging or edge defects are prone to occur; second, the anti-sagging performance is insufficient, and the solder paste flows after being coated on the vertical or curved substrate, resulting in uneven distribution of the brazing filler metal, and even short circuit risk; finally, component segregation and phase separation are prone to occur during storage and transportation, which affects the component uniformity of the brazing filler metal and the performance stability of the final joint. Therefore, developing a silver-copper-titanium active solder paste with high recovery coefficient and excellent comprehensive performance has become the key to solving the above problems. SUMMARY

[0004] In view of the poor thixotropy of the silver-copper-titanium active solder paste in the prior art, the application provides a silver-copper-titanium active solder paste with a high recovery coefficient and a preparation method and application thereof. By synergistically adjusting the component composition, ratio and preparation process of the solder paste, the silver-copper-titanium active solder paste with excellent thixotropy and a recovery coefficient close to 1 is prepared, which significantly improves the ability of the solder paste in printing forming, anti-sagging and storage stability, thereby effectively guaranteeing the process adaptability and joint reliability of the ceramic-metal connection process, and providing an innovative connection material solution for high-end equipment manufacturing.

[0005] The silver-copper-titanium active solder paste has high recovery coefficient and is composed of the following materials in percentage by mass: solder powder 70-90%, flux 10-30%; the solder powder is a mixed powder composed of silver-copper base powder, titanium-containing powder and other metal powder; the flux is composed of the following materials in percentage by mass: solvent 40-70%, rosin 20-40%, active agent 5-20%, thixotropic agent 1-15%, interface modifier 1-10%, corrosion inhibitor 1-10%, wherein the thixotropic agent is composed of short-range agent and long-range agent in a mass ratio of 1:1-4.

[0006] Preferably, the percentage by mass of the solder powder is 80-90% and the percentage by mass of the flux is 10-20%.

[0007] Further preferably, the percentage by mass of the solder powder is 85-90% and the percentage by mass of the flux is 10-15%.

[0008] Further, in the above technical solution, the silver-copper base powder is a mixed powder of silver powder and copper powder or a silver-copper alloy powder.

[0009] Further, in the above technical solution, the titanium-containing powder is titanium powder or titanium hydride powder.

[0010] Further, in the above technical solution, the other metal powder is selected from one or more of gold, lithium, aluminum, tin, indium, zinc, nickel, chromium, gallium, zirconium, palladium, lanthanum or cerium.

[0011] Further, in the above technical solution, the percentage by mass of silver in the solder powder is 0.1-90%; preferably 15-90%; more preferably 40-90%.

[0012] Further, in the above technical solution, the percentage by mass of copper in the solder powder is 0.1-90%; preferably 10-90%; more preferably 20-50%.

[0013] Further, in the above technical solution, the percentage by mass of titanium in the solder powder is 0.1-70%; preferably 0.1-30%; more preferably 0.1-15%.

[0014] Further, in the above technical solution, the percentage by mass of other metal in the solder powder is 0.1-30%; preferably 0.1-15%; more preferably 0.1-10%.

[0015] Further, in the above technical solution, the average particle size of the silver-copper-based powder, the titanium-containing powder, and the other metal powder in the brazing filler powder is independently selected from 0.1-300 μm; preferably 0.1-100 μm; more preferably 0.1-30 μm.

[0016] Further, in the above technical solution, the short-range agent is hydrogenated castor oil.

[0017] Further, in the above technical solution, the long-range agent is one of polyamide, polyamide wax, ethyl cellulose, or polyurea.

[0018] Further, in the above technical solution, the solvent is one or more of terpineol, diethylene glycol butyl ether acetate, dioctyl adipate, or dioctyl azelate.

[0019] Further, in the above technical solution, the active agent is one or more of potassium fluoroborate, potassium fluoride, cesium fluoride, or lithium fluoride.

[0020] Further, in the above technical solution, the interface modifier is one or more of aminopropyl triethoxysilane, propyl trimethoxysilane, or a dialkyl phosphate ester.

[0021] Further, in the above technical solution, the corrosion inhibitor is one or more of benzotriazole, monoethanolamine, triethanolamine, or 2-methylimidazole.

[0022] It is another object of the present application to provide a method for preparing the above silver-copper-titanium active solder paste, comprising the following steps: (1) proportionally weighing the silver-copper-based powder, the titanium-containing powder, and the other metal powder, ball milling at a speed of 20-500 r / min for 1-20 h, and drying at 60-200 ℃ for 10-200 min after the ball milling is completed to obtain a brazing filler powder; (2) adding a solvent and rosin into an ultrasonic disperser, heating to 60-75 ℃, and dispersing for 30-120 min until the rosin is completely dissolved to form a uniform transparent liquid; (3) adding an active agent into the liquid of step (2), ultrasonic dispersing at 60-75 ℃ for 10-60 min until the active agent is completely dispersed and uniformly mixed to obtain a mixed solution; (4) adding a thixotropic agent into the mixed solution of step (3), heating to 80-90 ℃, and ultrasonic dispersing for 20-90 min until the thixotropic agent is uniformly dispersed to form a uniform transparent colloid; (5) stopping the heating, adding an interface modifier into the colloid of step (4) and ultrasonic dispersing for 1-4 h until it is naturally cooled to room temperature, gradually thickens, loses transparency, and forms a uniform paste-like gel; (6) adding corrosion inhibitor into the gel prepared in step (5), and ultrasonic dispersing for 5-40 min at room temperature until it is uniformly dispersed to obtain a viscous paste-like flux; (7) mixing the flux prepared in step (6) with the solder powder prepared in step (1), and stirring for 10-60 min at room temperature by using a vacuum stirrer to obtain a bright and bubble-free solder paste.

[0023] Further, in the above technical solution, the ball milling time in step (1) is preferably 10-20 h; more preferably 15-20 h.

[0024] Further, in the above technical solution, the ball milling speed in step (1) is preferably 150-500 r / min; more preferably 200-300 r / min.

[0025] Further, in the above technical solution, the drying time in step (1) is preferably 100-200 min; more preferably 150-200 min.

[0026] Further, in the above technical solution, the drying temperature in step (1) is preferably 80-200 ℃; more preferably 120-200 ℃.

[0027] Further, in the above technical solution, the ultrasonic dispersing time in step (2) is preferably 60-120 min; more preferably 90-120 min.

[0028] Further, in the above technical solution, the ultrasonic dispersing time in step (3) is preferably 30-60 min; more preferably 30-40 min.

[0029] Further, in the above technical solution, the ultrasonic dispersing time in step (4) is preferably 40-80 min; more preferably 40-60 min.

[0030] Further, in the above technical solution, the ultrasonic dispersing time in step (5) is preferably 2-4 h; more preferably 2-3 h.

[0031] Further, in the above technical solution, the ultrasonic dispersing time in step (6) is preferably 10-40 min; more preferably 20-40 min.

[0032] Further, in the above technical solution, the vacuum stirring time in step (7) is preferably 30-60 min; more preferably 30-40 min.

[0033] Another object of the present application is to provide the application of the above-mentioned silver-copper-titanium active solder paste with high recovery coefficient in the field of heterogeneous material connection technology and semiconductor packaging.

[0034] The present application relates to a silver-copper-titanium active solder paste with high recovery coefficient and a preparation method thereof, belonging to the field of heterogeneous material connection technology and semiconductor packaging. The present application adopts a "short-range-long-range" synergistic thixotropic system, so that the three-dimensional network structure of the solder paste can be quickly reconstructed after shearing. At the same time, an interface modifier is introduced to effectively avoid the erosion of titanium element on the thixotropic agent, significantly improving the thixotropic performance of the solder paste, so that the recovery coefficient is close to 1. This key improvement effectively solves the shortcomings of traditional silver-copper-titanium active solder paste in terms of printing formability, anti-sagging ability and storage stability. The solder paste obtained by the present application has excellent printing suitability, can realize clear outline and full line fine pattern printing, and meets the stringent requirements of high-density packaging on solder coating. At the same time, it shows excellent anti-sagging performance (vertical sag height <0.5 mm), and can be stably coated on vertical walls and complex three-dimensional structure surfaces. In addition, the solder paste has good storage stability, effectively inhibits particle sedimentation and phase separation, and ensures uniform composition and consistent performance. The present application provides an innovative path for high-precision and automated connection of ceramic-metal, and is particularly suitable for high-end equipment manufacturing fields such as aerospace thermal protection systems, high-power electronic device packaging, high-temperature and high-pressure sensors, etc. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a photo of the silver-copper-titanium active solder paste prepared in Example 1. DETAILED DESCRIPTION

[0036] The following non-limiting examples can enable those skilled in the art to more fully understand the present application, but in no way limit the present application.

[0037] In the following examples, the test methods described are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0038] In the following examples, the recovery coefficient of the solder paste is measured by a rotary rheometer RheolabQC produced by Anton Paar (Shanghai) Trading Co., Ltd.

[0039] Example 1 In the process of preparing the flux, terpineol is selected as the solvent, potassium fluoroborate is selected as the active agent, hydrogenated castor oil is selected as the short-range agent, polyamide wax is selected as the long-range agent, aminopropyl triethoxysilane is selected as the interface modifier, and benzotriazole is selected as the corrosion inhibitor.

[0040] The silver-copper-titanium active solder paste is prepared according to the following steps: (1) 54.8 g of silver powder with an average particle size of 150 μm, 21.2 g of copper powder with an average particle size of 30 μm, and 4 g of titanium powder with an average particle size of 220 μm were weighed according to a mass ratio of 68.5 : 26.5 : 5, respectively, and mixed by ball milling at a rotation speed of 300 r / min for 6 h. After ball milling, drying was performed at 100 °C for 60 min, to obtain the solder powder; (2) 11 g of terpineol and 6 g of rosin were added to an ultrasonic disperser, heated to 70 °C, and dispersed for 60 min to form a uniform transparent liquid; (3) 1.6 g of potassium fluoroborate was added to the above liquid, and ultrasonic dispersion was performed at 65 °C for 30 min to obtain a mixed solution; (4) 0.4 g of hydrogenated castor oil and 0.8 g of polyamide wax were added to the above mixed solution, heated to 85 °C, and ultrasonic dispersed for 60 min to form a uniform transparent colloid; (5) Heating was stopped, 1.5 g of aminopropyltriethoxysilane was added to the above colloid, and ultrasonic dispersion was performed for 2.5 h until it was naturally cooled to room temperature, gradually thickened, and lost transparency to form a uniform paste-shaped gel; (6) 0.2 g of benzotriazole was added to the above gel, and ultrasonic dispersion was continued at room temperature for 20 min to obtain a flux; (7) The solder powder obtained in step (1) and the flux obtained in step (6) were mixed, and vacuum stirring was performed in a vacuum stirrer for 30 min to obtain a silver-copper-titanium solder paste, which had an appearance as shown in Figure 1 .

[0041] It was tested that the recovery coefficient R (60 s) of the solder paste obtained in the example was 0.92, the vertical flow hanging was 0.27 mm, there was no obvious sedimentation after standing for 168 h, the spreading rate on AlN ceramic was 78%, and the printed pattern was full. The shear strength of the AlN / Cu brazed joint prepared by using the solder as the solder was 128 MPa.

[0042] Example 2 In the preparation of the flux, diethylene glycol butyl ether acetate was selected as the solvent, potassium fluoride was selected as the active agent, hydrogenated castor oil was selected as the short-range agent, polyurea was selected as the long-range agent, propyl trimethoxysilane was selected as the interface modifier, and 2-methyl imidazole was selected as the corrosion inhibitor.

[0043] The silver-copper-titanium active solder paste was prepared according to the following steps: (1) 55.25 g of silver powder with an average particle size of 300 μm, 25.075 g of copper powder with an average particle size of 30 μm, and 4.675 g of titanium hydride powder with an average particle size of 150 μm were weighed according to a mass percentage of 65:29.5:5.5, respectively, and mixed by ball milling at a speed of 350 r / min for 8 h. After ball milling, drying was performed at 110 °C for 80 min, to obtain the solder powder; (2) 9 g of diethylene glycol butyl ether acetate and 3.75 g of rosin were added to an ultrasonic disperser, heated to 70 °C, and dispersed for 60 min to form a uniform transparent liquid; (3) 1.2 g of potassium fluoride was added to the above liquid, and ultrasonic dispersion was performed at 60 °C for 30 min to obtain a mixed solution; (4) 0.3 g of hydrogenated castor oil and 0.45 g of polyurea were added to the above mixed solution, heated to 88 °C, and ultrasonic dispersion was performed for 70 min to form a uniform transparent colloid; (5) Heating was stopped, 1 g of propyl trimethoxysilane was added to the above colloid, and ultrasonic dispersion was performed for 2.5 h until it was naturally cooled to room temperature, gradually thickened, and lost transparency to form a uniform paste-shaped gel; (6) 0.3 g of 2-methylimidazole was added to the above gel, and ultrasonic dispersion was continued at room temperature for 20 min to obtain a flux; (7) The solder powder obtained in step (1) was mixed with the flux obtained in step (6), and vacuum stirring was performed in a vacuum stirrer for 10 min to obtain a silver-copper-titanium solder paste.

[0044] It was tested that the recovery coefficient R (60 s) of the solder paste obtained in the embodiment was 0.95, the vertical flow hanging was 0.09 mm, there was no obvious sedimentation after standing for 168 h, the spreading rate on Si3N4 ceramic was 80%, and the printed pattern was full. The shear strength of the Si3N4 / 4J36 brazed joint prepared by using the solder as the solder was 131 MPa.

[0045] Example 3 In the preparation process of the flux, dioctyl adipate was selected as the solvent, lithium fluoride was selected as the active agent, hydrogenated castor oil was selected as the short-range agent, ethyl cellulose was selected as the long-range agent, bisalkyl phosphate was selected as the interface modifier, and triethanolamine was selected as the corrosion inhibitor.

[0046] The silver-copper-tin-titanium active solder paste was prepared according to the following steps: (1) 70.2 g of silver-copper alloy powder with an average particle size of 10 μm, 3.12 g of titanium powder with an average particle size of 20 μm, and 4.68 g of tin powder with an average particle size of 15 μm were weighed according to a mass ratio of 90:4:6, respectively, and mixed by ball milling at a speed of 400 r / min for 10 h. After ball milling, the mixture was dried at 90 °C for 90 min to obtain the solder powder; (2) 14.3 g of dioctyl adipate and 5.06 g of rosin were added to an ultrasonic disperser, heated to 70 °C, and dispersed for 60 min to form a uniform transparent liquid; (3) 1.54 g of lithium fluoride was added to the above liquid, and ultrasonic dispersion was performed at 60 °C for 30 min to obtain a mixed solution; (4) 0.27 g of hydrogenated castor oil and 0.5 g of ethyl cellulose were added to the above mixed solution, heated to 83 °C, and dispersed for 50 min to form a uniform transparent colloid; (5) The heating was stopped, 1.2 g of a dialkyl phosphate ester was added to the above colloid, and ultrasonic dispersion was performed for 2.5 h until it was naturally cooled to room temperature, gradually thickened, and lost transparency to form a uniform paste-shaped gel; (6) 0.33 g of triethanolamine was added to the above gel, and ultrasonic dispersion was continued at room temperature for 20 min to obtain a flux; (7) The solder powder obtained in step (1) and the flux obtained in step (6) were mixed, and vacuum stirring was performed in a vacuum stirrer for 20 min to obtain a silver-copper-tin-titanium solder paste.

[0047] It was detected that the recovery coefficient R (60 s) of the solder paste obtained in the example was 0.89, the vertical flow hanging was 0.37 mm, there was no obvious sedimentation after standing for 168 h, the spreading rate on ZrO2 ceramic was 76%, and the printed pattern was full. The shear strength of the ZrO2 / TZM brazed joint prepared by using the solder as the solder was 115 MPa.

[0048] Example 4 In the preparation process of the flux, terpineol was selected as the solvent, potassium fluoborate and cesium fluoride were selected as the activators, hydrogenated castor oil was selected as the short-range agent, polyamide wax was selected as the long-range agent, aminopropyl triethoxysilane was selected as the interface modifier, and benzotriazole was selected as the corrosion inhibitor.

[0049] The silver-copper-nickel-cerium-titanium active solder paste was prepared according to the following steps: (1) According to the mass percentage of 90:6:2:2, 79.2 g of silver-copper alloy powder with an average particle size of 200 μm, 5.28 g of titanium hydride powder with an average particle size of 100 μm, 1.76 g of nickel powder with an average particle size of 5 μm, and 1.76 g of cerium powder with an average particle size of 15 μm are weighed respectively, ball-mixed at a speed of 280 r / min for 12 h, and then dried at 115 ℃ for 100 min after ball-milling to obtain the solder powder; (2) 6 g of terpineol and 4.2 g of rosin are added into an ultrasonic disperser, heated to 70 ℃, and dispersed for 60 min to form a uniform transparent liquid; (3) 0.6 g of potassium fluoroborate and 0.6 g of cesium fluoride are added into the above liquid, ultrasonically dispersed at 70 ℃ for 30 min to obtain a mixed solution; (4) 0.2 g of hydrogenated castor oil and 0.22 g of polyamide wax are added into the above mixed solution, heated to 86 ℃, and dispersed for 80 min to form a uniform transparent colloid; (5) Stop heating, add 0.7 g of aminopropyltriethoxysilane, ultrasonically disperse for 2.5 h, and then naturally cool to room temperature, gradually thicken, lose transparency, and form a uniform paste-shaped gel; (6) 0.18 g of benzotriazole is added into the above gel, and ultrasonically dispersed at room temperature for 20 min to obtain a flux; (7) The solder powder obtained in step (1) and the flux obtained in step (6) are mixed, and vacuum stirred in a vacuum stirrer for 25 min to obtain a silver-copper-nickel-cerium-titanium solder paste.

[0050] It is detected that the recovery coefficient R (60 s) of the solder paste obtained in the embodiment is 0.9, the vertical flow hanging is 0.44 mm, there is no obvious sedimentation after standing for 168 h, the spreading rate on Al2O3 ceramic is 77%, and the printed pattern is full. The shear strength of the Al2O3 / Invar alloy brazed joint prepared by using the solder as the solder is 145 MPa.

[0051] Example 5 In the preparation process of the flux, terpineol is selected as the solvent, potassium fluoride is selected as the activator, hydrogenated castor oil is selected as the short-range agent, polyamide is selected as the long-range agent, propyltrimethoxysilane is selected as the interface modifier, and monoethanolamine is selected as the corrosion inhibitor.

[0052] The silver-copper-titanium active solder paste is prepared according to the following steps: (1) 56.8 g of silver powder with an average particle size of 50 μm, 19.2 g of copper powder with an average particle size of 230 μm, and 4 g of titanium powder with an average particle size of 25 μm were weighed according to a mass percentage of 71:24:5, respectively, and mixed by ball milling at a speed of 250 r / min for 5 h, and then dried at 95 ℃ for 70 min after ball milling to obtain a brazing filler powder; (2) 9 g of terpineol and 8 g of rosin were added to an ultrasonic dispersing machine, heated to 70 ℃, and dispersed for 60 min to form a uniform transparent liquid; (3) 1 g of potassium fluoride was added to the above liquid, and ultrasonic dispersion was performed at 70 ℃ for 30 min to obtain a mixed solution; (4) 0.3 g of hydrogenated castor oil and 0.5 g of polyamide were added to the above mixed solution, heated to 82 ℃, and dispersed for 40 min to form a uniform transparent colloid; (5) The heating was stopped, 0.5 g of propyltrimethoxysilane was added to the above colloid, and ultrasonic dispersion was performed for 2.5 h until it was naturally cooled to room temperature, gradually thickened, lost transparency, and formed a uniform paste-shaped gel; (6) 0.2 g of monoethanolamine was added to the above gel, and ultrasonic dispersion was continued at room temperature for 20 min to obtain a flux; (7) The brazing filler powder obtained in step (1) and the flux obtained in step (6) were mixed, and vacuum stirring was performed in a vacuum stirrer for 30 min to obtain a silver-copper-titanium solder paste.

[0053] It was detected that the recovery coefficient R(60 s) of the solder paste obtained in the embodiment was 0.88, the vertical flow hanging was 0.12 mm, there was no obvious sedimentation after standing for 168 h, the spreading rate on SiC ceramic was 75%, and the printed pattern was full. The shear strength of the SiC / TC4 brazed joint prepared by using the solder as a brazing filler metal was 120 MPa.

[0054] Example 6 In the preparation process of the flux, dioctyl adipate was selected as a solvent, lithium fluoride was selected as an activator, hydrogenated castor oil was selected as a short-range agent, polyamide wax was selected as a long-range agent, a dialkyl phosphate was selected as an interface modifier, and 2-methyl imidazole was selected as a corrosion inhibitor.

[0055] The silver-copper-titanium active solder paste was prepared according to the following steps: (1) 66.5 g of silver-copper alloy powder with an average particle size of 250 μm, 1.75 g of titanium powder with an average particle size of 30 μm, and 1.75 g of zinc powder with an average particle size of 10 μm were weighed according to a mass percentage of 95:2.5:2.5, respectively, and mixed by ball milling at a speed of 450 r / min for 20 h, and then dried at 80 ℃ for 120 min after ball milling to obtain a brazing filler powder; (2) 21 g dioctyl adipate and 6 g rosin were added into an ultrasonic disperser, heated to 70 °C, and dispersed for 60 min to form a uniform transparent liquid; (3) 1.5 g lithium fluoride was added into the above liquid, and ultrasonic dispersed for 30 min at 75 °C to obtain a mixed solution; (4) 0.4 g hydrogenated castor oil and 0.8 g polyamide wax were added into the above mixed solution, heated to 80 °C, and dispersed for 90 min to form a uniform transparent colloid; (5) The heating was stopped, 2.5 g bisalkyl phosphate was added into the above colloid, and ultrasonic dispersed for 2.5 h until it was naturally cooled to room temperature, gradually thickened, lost transparency, and formed a uniform paste gel; (6) 0.3 g 2-methylimidazole was added into the above gel, and ultrasonic dispersed for 20 min at room temperature to obtain a flux; (7) The solder powder obtained in step (1) and the flux obtained in step (6) were mixed, and vacuum stirred in a vacuum stirrer for 60 min to obtain a silver-copper-titanium solder paste.

[0056] It was detected that the recovery coefficient R (60 s) of the solder paste obtained in the embodiment was 0.93, the vertical flow hanging was 0.17 mm, there was no obvious sedimentation after standing for 168 h, the spreading rate on diamond ceramic was 79%, and the printed pattern was full. The shear strength of the diamond / Kovar alloy brazed joint prepared by using the solder as the solder was 125 MPa.

[0057] Example 7 In the preparation of the flux, terpineol was selected as the solvent, potassium fluoride was selected as the activator, hydrogenated castor oil was selected as the short-range agent, ethyl cellulose was selected as the long-range agent, aminopropyl triethoxysilane was selected as the interface modifier, and benzotriazole was selected as the corrosion inhibitor.

[0058] The silver-copper-nickel-titanium active solder paste was prepared according to the following steps: (1) Silver powder with an average particle size of 80 μm 58.93 g, copper powder with an average particle size of 300 μm 19.92 g, hydrogenated titanium powder with an average particle size of 20 μm 3.735 g, and nickel powder with an average particle size of 50 μm 0.415 g were weighed according to the mass percentage of 71 : 24 : 4.5 : 0.5, and ball-mixed at a speed of 320 r / min for 7 h. After ball-milling, drying was performed at 105 °C for 80 min to obtain a solder powder; (2) 10.2 g terpineol and 4.76 g rosin were added into an ultrasonic disperser, heated to 70 °C, and dispersed for 60 min to form a uniform transparent liquid; (3) 1.02 g of potassium fluoride was added into the above liquid and ultrasonic dispersed for 30 min at 65 °C to obtain a mixed solution; (4) 0.34 g of hydrogenated castor oil and 0.34 g of ethyl cellulose were added into the above liquid, heated to 84 °C and dispersed for 60 min to form a uniform transparent colloid; (5) The heating was stopped, 1 g of aminopropyl triethoxysilane was added into the above colloid, ultrasonic dispersed for 2.5 h, and the colloid was gradually thickened and lost transparency to form a uniform paste gel when it was naturally cooled to room temperature; (6) 0.34 g of benzotriazole was added into the above gel, and ultrasonic dispersed for 20 min at room temperature to obtain a flux; (7) The solder powder obtained in step (1) and the flux obtained in step (6) were mixed and vacuum stirred in a vacuum stirrer for 15 min to obtain a silver copper nickel titanium solder paste.

[0059] It was detected that the recovery coefficient R (60 s) of the solder paste obtained in the embodiment was 0.91, the vertical flow hanging was 0.48 mm, there was no obvious settlement after standing for 168 h, the spreading rate on ZrB2 ceramic was 80%, and the printed pattern was full. The shear strength of the ZrB2 / TZM brazed joint prepared by using the solder as the solder was 138 MPa.

[0060] Example 8 In the process of preparing the flux, terpineol was selected as the solvent, potassium fluoroborate was selected as the activator, hydrogenated castor oil was selected as the short-range agent, polyamide was selected as the long-range agent, propyl trimethoxysilane was selected as the interface modifier, and triethanolamine was selected as the corrosion inhibitor.

[0061] The silver copper titanium active solder paste was prepared according to the following steps: (1) 53.6 g of silver powder with an average particle size of 40 μm, 22.4 g of copper powder with an average particle size of 10 μm and 4 g of titanium powder with an average particle size of 300 μm were weighed according to the mass percentage of 67:28:5, ball-mixed at a speed of 270 r / min for 4.5 h, and then dried at 100 °C for 60 min after ball-milling to obtain a solder powder; (2) 14 g of terpineol and 5 g of rosin were added into an ultrasonic disperser, heated to 70 °C and dispersed for 60 min to form a uniform transparent liquid; (3) 0.6 g of potassium fluoroborate was added into the above liquid and ultrasonic dispersed for 30 min at 75 °C to obtain a mixed solution; (4) 0.13 g of hydrogenated castor oil and 0.17 g of polyamide were added into the above mixed solution, heated to 85 °C and dispersed for 30 min to form a uniform transparent colloid; (5) stop heating, add 1.6 g of propyl trimethoxysilane into the above colloid, ultrasonic dispersion for 2.5 h, until it is naturally cooled to room temperature, gradually thickened, lost transparency, and formed a uniform paste gel; (6) add 0.1 g of triethanolamine into the above gel, continue ultrasonic dispersion for 20 min at room temperature, to obtain a flux; (7) mix the brazing filler powder obtained in step (1) and the flux obtained in step (6) in a vacuum stirrer for 50 min, to obtain a silver copper titanium solder paste.

[0062] It is detected that the recovery coefficient R (60 s) of the solder paste obtained in the embodiment is 0.87, the vertical flow hanging is 0.35 mm, no obvious settlement is observed after standing for 168 h, the spreading rate on Al2O3 ceramic is 74%, and the printed pattern is full. The shear strength of the Al2O3 / C-276 brazed joint prepared by using the solder as the brazing filler metal is 118 MPa.

[0063] Example 9 In the preparation of the flux, diethylene glycol butyl ether acetate is selected as the solvent, potassium fluoride is selected as the activator, hydrogenated castor oil is selected as the short-range agent, polyamide wax is selected as the long-range agent, bis-alkyl phosphate is selected as the interface modifier, and benzotriazole is selected as the corrosion inhibitor.

[0064] The silver copper indium titanium active solder paste is prepared according to the following steps: (1) according to the mass percentage of 93.5 : 5 : 1.5, 72.93 g of silver copper alloy powder with an average particle size of 20 μm, 3.9 g of titanium hydride powder with an average particle size of 150 μm, and 1.17 g of indium powder with an average particle size of 200 μm are weighed, and ball-mixed for 9 h at a rotation speed of 330 r / min, and then dried at 115 ℃ for 90 min after ball-milling, to obtain a brazing filler powder; (2) add 11 g of diethylene glycol butyl ether acetate and 6.6 g of rosin into an ultrasonic dispersion machine, heat to 70 ℃, and disperse for 60 min, to form a uniform transparent liquid; (3) add 2.2 g of potassium fluoride into the above liquid, ultrasonic dispersion for 30 min at 65 ℃, to obtain a mixed solution; (4) add 0.5 g of hydrogenated castor oil and 1.26 g of polyamide wax into the above mixed solution, heat to 90 ℃, and disperse for 90 min, to form a uniform transparent colloid; (5) stop heating, add 0.6 g of bis-alkyl phosphate into the above colloid, ultrasonic dispersion for 2.5 h, until it is naturally cooled to room temperature, gradually thickened, lost transparency, and formed a uniform paste gel; (6) 0.44 g benzotriazole was added into the above gel, and ultrasonic dispersion was continued at room temperature for 20 min to obtain a flux; (7) The brazing filler metal powder obtained in step (1) and the flux obtained in step (6) were mixed, and vacuum stirring was performed in a vacuum stirrer for 40 min to obtain a silver-copper-indium-titanium solder paste.

[0065] It was detected that the recovery coefficient R (60 s) of the solder paste obtained in the embodiment was 0.96, the vertical flow hanging was 0.07 mm, no obvious settlement was observed after standing for 168 h, the spreading rate on Si3N4 ceramic was 77%, and the printed pattern was full. The shear strength of the Si3N4 / 4J29 brazed joint prepared by using the solder as the brazing filler metal was 110 MPa.

[0066] Example 10 In the preparation of the flux, terpineol was selected as the solvent, cesium fluoride was selected as the activator, hydrogenated castor oil was selected as the short-range agent, polyurea was selected as the long-range agent, aminopropyl triethoxysilane was selected as the interface modifier, and 2-methyl imidazole was selected as the corrosion inhibitor.

[0067] The silver-copper-tin-gallium-zirconium-titanium active solder paste was prepared according to the following steps: (1) 49.8 g of silver powder with an average particle size of 15 μm, 16.6 g of copper powder with an average particle size of 230 μm, 3.32 g of titanium hydride powder with an average particle size of 100 μm, 8.3 g of tin powder with an average particle size of 70 μm, 2.49 g of gallium powder with an average particle size of 5 μm, and 2.49 g of zirconium powder with an average particle size of 120 μm were weighed according to the mass percentage of 60:20:4:10:3:3, and were ball-mixed at a rotating speed of 380 r / min for 15 h. After ball-milling, drying was performed at 120 °C for 110 min to obtain a brazing filler metal powder; (2) 10.2 g of terpineol and 4.76 g of rosin were added into an ultrasonic disperser, heated to 70 °C, and dispersed for 60 min to form a uniform transparent liquid; (3) 1.19 g of cesium fluoride was added into the above liquid, and ultrasonic dispersion was performed at 70 °C for 30 min to obtain a mixed solution; (4) 0.25 g of hydrogenated castor oil and 0.345 g of polyurea were added into the above mixed solution, heated to 88 °C, and dispersed for 70 min to form a uniform transparent colloid; (5) The heating was stopped, 0.4 g of aminopropyl triethoxysilane and 0.5 g of a dialkyl phosphate ester were added into the above colloid, ultrasonic dispersion was performed for 2.5 h, and the colloid was naturally cooled to room temperature, gradually thickened, and lost transparency to form a uniform paste-shaped gel; (6) 0.255 g 2-methylimidazole was added into the above gel, and ultrasonic dispersion was continued at room temperature for 20 min to obtain a flux; (7) The brazing filler metal powder obtained in step (1) and the flux obtained in step (6) were mixed, and vacuum stirring was performed in a vacuum stirrer for 35 min to obtain a silver copper tin gallium zirconium titanium solder paste.

[0068] It was detected that the recovery coefficient R (60 s) of the solder paste obtained in the embodiment was 0.89, the vertical flow hanging was 0.19 mm, no obvious settlement occurred after standing for 168 h, the spreading rate on SiC ceramic was 81%, and the printed pattern was full. The shear strength of a SiC / TC4 brazed joint prepared by using the solder as a brazing filler metal was 122 MPa.

[0069] Comparative Example 1 In the preparation process of the flux, terpineol was selected as a solvent, potassium fluoroborate was selected as an activator, hydrogenated castor oil was selected as a thixotropic agent, aminopropyl triethoxysilane was selected as an interface modifier, and benzotriazole was selected as a corrosion inhibitor.

[0070] The difference between the comparative example and the embodiment 1 is that only hydrogenated castor oil is selected as a thixotropic agent, no long-range agent is added, the addition amount of the hydrogenated castor oil is 1.2 g, and the rest of the operations are the same as those in the embodiment 1.

[0071] It was detected that the recovery coefficient R (60 s) of the solder paste obtained in the comparative example was 0.74, the vertical flow hanging was 2.4 mm, obvious settlement occurred after standing for 48 h, the spreading rate on AlN ceramic was 56%, and the printed pattern was collapsed.

[0072] Comparative Example 2 In the preparation process of the flux, terpineol was selected as a solvent, potassium fluoroborate was selected as an activator, polyamide wax was selected as a thixotropic agent, aminopropyl triethoxysilane was selected as an interface modifier, and benzotriazole was selected as a corrosion inhibitor.

[0073] The difference between the comparative example and the embodiment 1 is that only polyamide wax is selected as a thixotropic agent, no short-range agent is added, the addition amount of the polyamide wax is 1.2 g, and the rest of the operations are the same as those in the embodiment 1.

[0074] It was detected that the recovery coefficient R (60 s) of the solder paste obtained in the comparative example was 0.7, the vertical flow hanging was 1.6 mm, obvious settlement occurred after standing for 52 h, the spreading rate on AlN ceramic was 56%, and the printed pattern was collapsed.

[0075] Comparative Example 3 In the preparation process of the flux, terpineol was selected as a solvent, potassium fluoroborate was selected as an activator, hydrogenated castor oil was selected as a short-range agent, polyamide wax was selected as a long-range agent, and benzotriazole was selected as a corrosion inhibitor.

[0076] The difference between this comparative example and Example 1 is that no interfacial modifier is added, and the rest of the operations are the same as those in Example 1.

[0077] It is tested that the recovery coefficient R (60 s) of the solder paste obtained in this comparative example is 0.8, the vertical flow hanging is 1.4 mm, obvious settlement occurs after standing for 60 h, the spreading rate on the AlN ceramic is 64%, and the printed pattern collapses.

Claims

1. A high-k-factor silver copper titanium active solder paste characterized by: The soldering paste is composed of the following materials in percentage by mass: soldering powder 70%-90%, flux 10%-30%; the soldering powder is a mixed powder composed of silver-copper-based powder, titanium-containing powder and other metal powder; the flux is composed of the following materials in percentage by mass: solvent 40%-70%, rosin 20%-40%, active agent 5%-20%, thixotropic agent 1%-15%, interface modifier 1%-10%, corrosion inhibitor 1%-10%, wherein the thixotropic agent is composed of short-range agent and long-range agent in a mass ratio of 1:1-4.

2. The silver copper titanium active solder paste of claim 1, wherein: The silver-copper-based powder is a mixed powder of silver powder and copper powder or silver-copper alloy powder; the titanium-containing powder is titanium powder or titanium hydride powder; the other metal powder is selected from one or more of gold, lithium, aluminum, tin, indium, zinc, nickel, chromium, gallium, zirconium, palladium, lanthanum or cerium.

3. The silver copper titanium active solder paste of claim 1, wherein: The silver-copper-based powder, titanium-containing powder and other metal powder in the soldering powder are independently selected from 0.1-300 μm in average particle size.

4. The silver-copper-titanium active solder paste of claim 1, wherein: The short-range agent is hydrogenated castor oil; the long-range agent is one of polyamide, polyamide wax, ethyl cellulose or polyurea.

5. The silver-copper-titanium active solder paste of claim 1, wherein, The solvent is one or more of terpineol, diethylene glycol butyl ether acetate, dioctyl adipate or dioctyl azelate.

6. The silver-copper-titanium active solder paste of claim 1, wherein: The active agent is one or more of potassium fluoborate, potassium fluoride, cesium fluoride or lithium fluoride.

7. The silver-copper-titanium active solder paste of claim 1, wherein: The interface modifier is one or more of aminopropyl triethoxysilane, propyl trimethoxysilane or dialkyl phosphate.

8. The silver-copper-titanium active solder paste of claim 1, wherein, The corrosion inhibitor is one or more of benzotriazole, monoethanolamine, triethanolamine or 2-methyl imidazole.

9. The silver-copper-titanium active solder paste of claim 1, wherein: The method comprises the following steps:

10. A method of producing the silver-copper-titanium active solder paste according to any one of claims 1 to 9, characterized in that: (1) proportionally weigh the silver-copper-based powder, titanium-containing powder and other metal powder, ball mill at a speed of 20-500 r / min for 1-20 h, and dry at 60-200 ℃ for 10-200 min after ball milling to obtain the soldering powder; (2) add the solvent and rosin into an ultrasonic disperser, heat to 60-75 ℃, and ultrasonically disperse for 30-120 min until the rosin is completely dissolved to form a uniform transparent liquid; (3) add the active agent into the liquid in step (2), ultrasonically disperse at 60-75 ℃ for 10-60 min until the active agent is completely dispersed and uniformly mixed to obtain a mixed solution; (4) add the thixotropic agent into the mixed solution in step (3), heat to 80-90 ℃, and ultrasonically disperse for 20-90 min until the thixotropic agent is uniformly dispersed to form a uniform transparent colloid; (5) stop heating, add the interface modifier into the colloid in step (4), and ultrasonically disperse for 1-4 h until it is naturally cooled to room temperature, gradually thickens, loses transparency, and forms a uniform paste-shaped gel; (6) add the corrosion inhibitor into the gel in step (5), ultrasonically disperse at room temperature for 5-40 min until it is uniformly dispersed to obtain a viscous paste-shaped flux. ​ (7) The flux prepared in step (6) is mixed with the solder powder prepared in step (1), and stirred at room temperature for 10-60 min by a vacuum stirrer to obtain a bright and bubble-free solder paste.

Images