Solder paste for signal processing substrate and preparation method thereof

Abstract

The invention discloses a solder paste for a signal processing substrate and a preparation method thereof. The method comprises the following steps: 1) mixing Sn-Zn alloy, copper, indium, chloroauric acid hydrated, polyvinylpyrrolidone, a reducing agent and water to enable contact reaction so as to obtain an activating metal composition; 2) heating and dissolve rosin, rosin amine, organic acid, imidazole and tris(2-carboxyethyl) isocyanurate to obtain mixed liquor I; 3) mixing the mixed liquor I, a thixotropic agent and a preservative, and then cooling to obtain mixed liquor II; 4) mixing the mixed liquor II and polyethylene glycol to obtain a soldering flux; 5) refrigerating the soldering flux, and then performing dispersion mixing for the soldering flux and the activating metal composition under a vacuum condition and in the presence of X-rays, so as to obtain the solder paste for the signal processing substrate. The solder paste prepared by the preparation method is outstanding in chemical stability, low in welding temperature, and outstanding in expansion rate.

Description

technical field

[0001] The invention relates to solder paste, in particular to a solder paste for a signal processing substrate and a preparation method thereof. Background technique

[0002] Due to the introduction of relevant environmental protection regulations such as Rohs and REACH in the European Union, lead in traditional tin-lead alloys has been gradually replaced by lead-free alloys containing silver and bismuth under environmental bans. However, silver is a rare non-renewable resource. As the market's demand for electronic products continues to expand, and the replacement cycle of electronic products is getting shorter and shorter, silver is constantly being consumed, and the price of silver keeps rising, resulting in high costs.

[0003] The existing lead-free solders are basically Sn-based alloys, which contain a large proportion of Sn and one or more alloying elements, such as: Ag, Cu, Bi, In, Sb or Zn. Among them, Sn-based solders containing Ag (Sn-Ag-based so...

Examples

preparation example Construction

[0021] The invention provides a method for preparing a solder paste for a signal processing substrate, comprising:

[0022] 1) Mixing Sn-Zn alloy, copper, indium, chloroauric acid tetrahydrate, polyvinylpyrrolidone, reducing agent and water for contact reaction to prepare an activated metal composition;

[0023] 2) heating and dissolving rosin, rosin amine, organic acid, imidazole, and tris(2-carboxyethyl)isocyanurate to obtain mixed solution I;

[0024] 3) mixing the mixed solution I, the thixotropic agent and the preservative, and then cooling to obtain the mixed solution II;

[0025] 4) mixing liquid II with polyethylene glycol to prepare soldering flux;

[0026] 5) Refrigerating the soldering flux; then, in the presence of X-rays, disperse and mix it with the activated metal composition under vacuum to prepare a solder paste for signal processing substrates.

[0027] In step 1) of the method, the amount of each material can be selected in a wide range. On the premise of ...

Embodiment 1

[0044] 1) Sn-Zn alloy (containing 88% by weight of tin and 12% by weight of zinc), copper, indium, chloroauric acid tetrahydrate, polyvinylpyrrolidone (weight average molecular weight is 2500), reducing agent (sodium citrate) Mix with water according to the weight ratio of 100:0.7:2.4:13:12:13:180, and conduct a contact reaction at 80°C for 4 hours to prepare an activated metal composition;

[0045] 2) Mix rosin, rosin amine, organic acid (malic acid), imidazole, and tris(2-carboxyethyl)isocyanurate in a weight ratio of 100:35:20:13:7, and heat at 155°C Heating and dissolving for 70min to prepare mixed solution I;

[0046] 3) Mix the mixed solution I, the thixotropic agent (fumed silica) and the preservative (sodium nitrite) according to the weight ratio of 100:19:22, and then cool to 25°C to prepare the mixed solution II;

[0047] 4) Mix the mixed solution II with polyethylene glycol (100:11 by weight) to prepare flux;

[0048] 5) The flux was refrigerated at 3°C ​​for 17 h...

Embodiment 2

[0050] 1) Sn-Zn alloy (containing 85% by weight of tin and 15% by weight of zinc), copper, indium, chloroauric acid tetrahydrate, polyvinylpyrrolidone (weight average molecular weight is 1500), reducing agent (sodium citrate) Mix with water in a weight ratio of 100:0.3:2:10:8:10:150, and conduct a contact reaction at 75°C for 2 hours to prepare an activated metal composition;

[0051] 2) Mix rosin, rosin amine, organic acid (salicylic acid), imidazole, and tris(2-carboxyethyl)isocyanurate in a weight ratio of 100:30:15:9:3, and heat at 145°C Under heating and dissolving for 50min to obtain mixed solution I;

[0052] 3) Mix the mixed solution I, the thixotropic agent (fluorobentonite) and the preservative (hydroquinone) according to the weight ratio of 100:18:17, and then cool to 15°C to prepare the mixed solution II;

[0053] 4) Mix the mixed solution II with polyethylene glycol (100:7 by weight) to prepare flux;

[0054] 5) The flux was refrigerated at 1°C for 15 hours; the...

technical field

[0001] The invention relates to solder paste, in particular to a solder paste for a signal processing substrate and a preparation method thereof. Background technique

[0002] Due to the introduction of relevant environmental protection regulations such as Rohs and REACH in the European Union, lead in traditional tin-lead alloys has been gradually replaced by lead-free alloys containing silver and bismuth under environmental bans. However, silver is a rare non-renewable resource. As the market's demand for electronic products continues to expand, and the replacement cycle of electronic products is getting shorter and shorter, silver is constantly being consumed, and the price of silver keeps rising, resulting in high costs.

[0003] The existing lead-free solders are basically Sn-based alloys, which contain a large proportion of Sn and one or more alloying elements, such as: Ag, Cu, Bi, In, Sb or Zn. Among them, Sn-based solders containing Ag (Sn-Ag-based so...

Examples

preparation example Construction

[0021] The invention provides a method for preparing a solder paste for a signal processing substrate, comprising:

[0022] 1) Mixing Sn-Zn alloy, copper, indium, chloroauric acid tetrahydrate, polyvinylpyrrolidone, reducing agent and water for contact reaction to prepare an activated metal composition;

[0023] 2) heating and dissolving rosin, rosin amine, organic acid, imidazole, and tris(2-carboxyethyl)isocyanurate to obtain mixed solution I;

[0024] 3) mixing the mixed solution I, the thixotropic agent and the preservative, and then cooling to obtain the mixed solution II;

[0025] 4) mixing liquid II with polyethylene glycol to prepare soldering flux;

[0026] 5) Refrigerating the soldering flux; then, in the presence of X-rays, disperse and mix it with the activated metal composition under vacuum to prepare a solder paste for signal processing substrates.

[0027] In step 1) of the method, the amount of each material can be selected in a wide range. On the premise of ...

Embodiment 1

[0044] 1) Sn-Zn alloy (containing 88% by weight of tin and 12% by weight of zinc), copper, indium, chloroauric acid tetrahydrate, polyvinylpyrrolidone (weight average molecular weight is 2500), reducing agent (sodium citrate) Mix with water according to the weight ratio of 100:0.7:2.4:13:12:13:180, and conduct a contact reaction at 80°C for 4 hours to prepare an activated metal composition;

[0045] 2) Mix rosin, rosin amine, organic acid (malic acid), imidazole, and tris(2-carboxyethyl)isocyanurate in a weight ratio of 100:35:20:13:7, and heat at 155°C Heating and dissolving for 70min to prepare mixed solution I;

[0046] 3) Mix the mixed solution I, the thixotropic agent (fumed silica) and the preservative (sodium nitrite) according to the weight ratio of 100:19:22, and then cool to 25°C to prepare the mixed solution II;

[0047] 4) Mix the mixed solution II with polyethylene glycol (100:11 by weight) to prepare flux;

[0048] 5) The flux was refrigerated at 3°C ​​for 17 h...

Embodiment 2

[0050] 1) Sn-Zn alloy (containing 85% by weight of tin and 15% by weight of zinc), copper, indium, chloroauric acid tetrahydrate, polyvinylpyrrolidone (weight average molecular weight is 1500), reducing agent (sodium citrate) Mix with water in a weight ratio of 100:0.3:2:10:8:10:150, and conduct a contact reaction at 75°C for 2 hours to prepare an activated metal composition;

[0051] 2) Mix rosin, rosin amine, organic acid (salicylic acid), imidazole, and tris(2-carboxyethyl)isocyanurate in a weight ratio of 100:30:15:9:3, and heat at 145°C Under heating and dissolving for 50min to obtain mixed solution I;

[0052] 3) Mix the mixed solution I, the thixotropic agent (fluorobentonite) and the preservative (hydroquinone) according to the weight ratio of 100:18:17, and then cool to 15°C to prepare the mixed solution II;

[0053] 4) Mix the mixed solution II with polyethylene glycol (100:7 by weight) to prepare flux;

[0054] 5) The flux was refrigerated at 1°C for 15 hours; the...