Vacuum eutectic slurry for volatilizing auxiliary components at low temperature, and preparation and use methods thereof

Abstract

The invention discloses vacuum eutectic slurry with auxiliary components volatilized at low temperature and a preparation and use method, and relates to the technical field of microelectronic packaging, the vacuum eutectic slurry comprises main components and the auxiliary components, the purity of the main components is larger than 90%, the main components are soft solder alloy powder and / or metal elementary substance powder, and the auxiliary components are metal elementary substance powder. The auxiliary components comprise a plurality of reagents which are volatilized at low temperature. After the eutectic slurry is used, the eutectic voidage is reduced by adopting a low-vacuum bubble breaking method instead of using a friction action to reduce the eutectic voidage in eutectic. And a special eutectic soldering lug for each component is not needed any more, so that the production flexibility is improved. The auxiliary components are not easy to volatilize at room temperature, and the auxiliary components are easy to volatilize at 80-200 DEG C, so that no residue is left after volatilization, and no corrosion is caused to soft solder powder and components.

Description

Technical Field

[0001] The present invention relates to the technical field of microelectronic packaging, and more specifically to the technical field of vacuum eutectic slurry of low-temperature volatilization auxiliary components, and preparation and use methods thereof. Background Art

[0002] In microelectronic packaging, bare chips and components are mounted on substrates or lead frames in two ways: bonding and welding. The bonding process is mature, simple to operate, and highly automated. The disadvantage is that most colloids have low thermal conductivity. After long-term high-temperature use, the colloids will carbonize and the shear force will decrease, which will bring unpredictable instability factors to long-life electronic systems. In the face of high-heat devices or high-temperature environments, welding is usually used. Welding is divided into flux welding and flux-free welding, and eutectic welding is a type of flux-free welding. During eutectic formation, the solder is heated and melted, and the molten solder diffuses into the base material to form a new alloy phase to achieve welding. Commonly used eutectic solders include gold-tin, gold-germanium, and gold-silicon, and there are two eutectic methods: vacuum eutectic and friction eutectic.

[0003] Vacuum eutectic requires the production of various limit pressure devices. Each component of the eutectic must use a special solder sheet. Before eutectic, the eutectic substrate is placed in the limit pressure device, and then the solder sheet and eutectic components are placed into the eutectic area manually or automatically. The eutectic device is then pressurized and finally heated and melted in a vacuum furnace to achieve eutectic operation. The eutectic pressurization device has very high requirements for processing accuracy and material thermal expansion coefficient, resulting in high processing costs for the device, which is very unfavorable for small batch and multi-variety production.

[0004] Friction eutectics require friction during eutectic formation to reduce the eutectic void rate through friction. There are two types of friction eutectics: manual friction and automatic friction. Manual friction is suitable for multiple varieties and small batches, and is flexible in production. At this stage of the packaging market, there are some automatic friction eutectic equipment, but its automation maturity is far less than that of the bonding process, and the eutectic components still require special solder sheets. When there are a large number of eutectic components, automatic friction eutectics can only achieve friction eutectics for some devices, and most devices still belong to swing-piece melting welding. This will result in a small void rate for components using friction eutectic welding, and a large void rate for components using swing-piece melting welding.

[0005] There are many no-clean, low-residue solder paste products on the microelectronics packaging market, but they are only suitable for secondary packaging products. For hybrid integrated circuits or primary packaging products, these no-clean, low-residue solder paste products cannot be used directly, as they will emit some gases that affect the moisture content of the product, and some of the acidic or alkaline components will make the integrated circuit ineffective. Summary of the invention

[0006] The purpose of the present invention is to solve the above-mentioned existing technical problems and provide a vacuum eutectic slurry of a low-temperature volatilization auxiliary component and a preparation and use method thereof.

[0007] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0008] The first aspect of the present invention provides a vacuum eutectic slurry with a low-temperature volatilization auxiliary component, including a main component and an auxiliary component. The main component has a purity greater than 90%, and the main component is a solder alloy powder and / or a metal element powder. The auxiliary component includes a variety of low-temperature volatilization reagents.

[0009] Specifically, after the eutectic slurry is used, the eutectic no longer uses friction to reduce the eutectic void rate, but uses a low vacuum bubble breaking method to reduce the eutectic void rate. Eutectic-specific solder sheets for each component are no longer required, which improves production flexibility. The auxiliary components are not easy to volatilize at room temperature, and the auxiliary components are easy to volatilize at 80℃ to 200℃. There is no residue after volatilization, and there is no corrosion to the solder powder and components.

[0010] In one embodiment, the main component is a metal powder and / or a solder alloy powder having a melting point below 500°C.

[0011] In one embodiment, the metal single substance powder and the solder alloy powder are both in the form of flakes or spheres, and the particle sizes of the metal single substance powder and the solder alloy powder are both in the range of 2400 to 500 meshes.

[0012] In one embodiment, the main component powder is one or more of gold-tin powder, gold-germanium powder, tin-lead powder, indium-lead powder, tin-silver-copper powder or indium powder.

[0013] Specifically, the main component powder includes but is not limited to gold tin, gold germanium, tin lead, indium lead, tin silver copper, and indium powder. The main component powder has the characteristics of low oxidation degree and easy reduction under the action of reducing gas. The main component powder can be well dispersed in the reagent of the auxiliary component.

[0014] In one embodiment, the auxiliary component is one or more of a flux, a thickener, a dispersant, a wetting agent, a thixotropic agent, and a coupling agent.

[0015] Specifically, vacuum eutectic slurry consists of two parts, namely the main component and the auxiliary component. The main component is various solder alloy powders or metal element powders, which play a role in welding. The auxiliary components are a variety of low-temperature volatile reagents, including flux, thickener, dispersant, wetting agent, thixotropic agent and coupling agent. The auxiliary components are responsible for wetting or dispersing various solder powders to form slurry for pasting components, and do not participate in the final welding reaction.

[0016] In one embodiment, the auxiliary component is one or more of terpineol, ethanol, ethylene glycol, propylene glycol, glycerol, nonylphenol, n-hexanoic acid and perfluorooctane.

[0017] The second aspect of the present invention provides a method for preparing a vacuum eutectic slurry of a low-temperature volatilization auxiliary component, which is used to prepare the above-mentioned vacuum eutectic slurry of a low-temperature volatilization auxiliary component, comprising the following steps:

[0018] S1. Select the main components and auxiliary components for preparing the slurry.

[0019] S11, the main component is gold-tin alloy, and the auxiliary components are propylene glycol, nonylphenol, hexanoic acid and perfluorooctanoic acid;

[0020] S12, determining the proportion of each component of the gold-tin alloy, glycerol, nonylphenol, hexanoic acid and perfluorooctanoic acid, and preparing a eutectic slurry by fully stirring, wherein the dynamic viscosity of the eutectic slurry is between 1800 and 2400 centipoise (the slurry is stirred for 20 minutes to allow the auxiliary components to dissolve each other, and the gold-tin powder is fully dispersed in the slurry, and the viscosity is about 2100 centipoise);

[0021] In one embodiment, in step S11, the gold-tin alloy is prepared by a high-temperature and high-viscosity dispersion powder making method to prepare No. 8 gold-tin powder with low impurities and little oxidation, with a melting point of 280° C., and a reducing agent or an inert gas is added during the powder making process for protection to ensure that the prepared gold-tin powder meets the pulping process requirements;

[0022] In one embodiment, in step S12, gold-tin alloy, propylene glycol, nonylphenol, hexanoic acid and perfluorooctanoic acid are mixed in a mass ratio of 80﹕10﹕5:2.5﹕2.5, and 40 grams of gold-tin powder, 5 grams of propylene glycol, 2.5 grams of nonylphenol, 1.5 grams of hexanoic acid and 1.5 grams of perfluorooctanoic acid are weighed and then thoroughly mixed.

[0023] The third aspect of the present invention provides a method for using a vacuum eutectic slurry of a low-temperature volatilization auxiliary component, and the vacuum eutectic slurry is prepared using the above-mentioned method for preparing a low-temperature volatilization auxiliary component, comprising the following steps:

[0024] A1. Introduce the evenly stirred eutectic slurry into the glue cartridge, store it in a refrigerator at 5-8°C, install it on the automatic glue dispensing machine, and make glue dispensing calibration;

[0025] A2. Prepare the dispensing program, place the product on the workbench, and apply the eutectic slurry on the area where eutectic is required;

[0026] A3. Take out the product coated with slurry, put it into the automatic placement machine, and place the components to be eutectic into the corresponding positions as required;

[0027] A4. Take out the product with components attached and put it into the vacuum eutectic furnace;

[0028] A5. Set the eutectic furnace heating curve. The first stage of the heating is responsible for volatilizing the auxiliary components of the slurry, the second stage of the heating is responsible for reducing the oxides with reducing gas, and the third stage of the heating is responsible for melting the solder to achieve welding;

[0029] A6. After the first stage of heating, the volatilized gas of the auxiliary components and the oxygen in the air are extracted, and then nitrogen is filled and vacuumed to replace the residual gas, and finally protective or reducing gas is filled; in the second stage of heating, sufficient time should be left for the reducing gas to reduce the oxide; in the third stage of heating, low pressure is used to break the bubbles, and then positive pressure is filled to compress the bubbles that have not been broken, so as to reduce the eutectic void rate;

[0030] A7. Start the vacuum eutectic furnace. The eutectic furnace runs according to the designed curve. When the temperature reaches the melting point of the solder, the solder powder melts into liquid and connects together, filling the space between the components and the substrate to form a weld. At this time, there is an operation of first evacuating the vacuum and then filling it with positive pressure, which greatly reduces the void rate of the eutectic soldering.

[0031] A8. After the equipment is finished running, take out the product for void rate detection and quality inspection, and the process is completed.

[0032] The beneficial effects of the present invention are as follows:

[0033] 1. The use of the slurry of the present invention greatly simplifies the eutectic operation and greatly improves the eutectic automation rate. During eutectic formation, a dedicated pressure-limiting device is no longer required, which reduces the cost of eutectic fixtures and reduces production costs. Special friction eutectic equipment and eutectic solder sheets are no longer required. The use of an automatic dispensing machine and a chip mounter for bonding, combined with a vacuum eutectic furnace, can greatly improve the automated eutectic capacity and avoid repeated investment in equipment and the problem that eutectic must use a dedicated solder sheet.

[0034] 2. To prevent the resin from diffusing during the use of adhesive, contaminating the wire bonding pads and causing poor wire bonding, and to prevent the volatile gas from affecting the moisture content of the product, a new vacuum eutectic slurry was prepared. Eutectic slurry can replace adhesive for product packaging, and with the temperature gradient of welding, it can realize the full welding process of microelectronic packaging products without introducing any pollution, thus ensuring the moisture content and product quality of the product.

[0035] 3. Using gold-tin solder (Au80Sn20) No. 8 powder as the main component of the slurry, glycerol, nonylphenol, hexanoic acid and perfluorooctanoic acid as auxiliary components, gold-tin eutectic slurry was prepared. The dispersibility, wettability and thixotropy of the slurry are very ideal. In addition, the molecular weight and melting point of glycerol, nonylphenol and perfluorooctanoic acid are very low, and they can be completely volatilized at 120-150 degrees without any residue. The void rate of the gallium nitride chip of the gold-tin slurry eutectic is less than 5%, and it is scattered small dots. The reason for the formation of the dot voids is that during the eutectic process, large bubbles are broken by low vacuum, and small bubbles that cannot be broken are compressed by positive pressure gas, forming small dot voids. These scattered small dot voids do not have any effect on the heat dissipation of the chip because it is sufficiently dispersed. The use effect of gold-tin eutectic slurry is good.

[0036] 4. Using SAC305 (tin-silver-copper) No. 8 powder solder as the main component, and using glycerol, nonylphenol, hexanoic acid and perfluorooctanoic acid of analytical alcohol as auxiliary components, a tin-silver-copper eutectic slurry was prepared. The dispersibility, wettability and thixotropy of the slurry are very ideal. The slurry is coated on the PCB board using the screen printing process, and then the patch is carried out. Finally, the PCB board is placed in a vacuum reflow furnace. The auxiliary components are first volatilized and then melted and welded in the vacuum reflow furnace. The welding effect is good. The process does not cause the problem that the flux is difficult to clean after high-temperature welding. It is particularly beneficial for the stacking welding of PCB boards and components. There is no need to clean it at all, and the effect is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 It is the vacuum welding process curve used by the slurry;

[0039] Figure markings: 1-temperature curve, 2-heating to volatilize auxiliary components, 3-evacuating volatilized auxiliary components, 4-filling with replacement nitrogen, 5-evacuating the replacement gas, 6-filling with reducing gas such as formic acid, hydrogen or carbon monoxide, 7-reducing gas reacts with oxide to form salt, 8-salt is reduced to metal, 9-evacuating large bubbles in the welding area, 10-filling with nitrogen to break the vacuum, 11-filling with high-pressure nitrogen to compress small bubbles, 12-initial volatilization temperature, 13-middle reaction temperature one, 14-middle reaction temperature two, 15-final melting welding temperature. DETAILED DESCRIPTION

[0040] In order to make the technical problems, technical solutions and technical effects of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In addition, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0043] In the description of the embodiments of the present invention, it should be noted that the terms "inside", "outside", "upper", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0044] Example 1

[0045] This embodiment provides a vacuum eutectic slurry with a low-temperature volatilization auxiliary component, including a main component and an auxiliary component. The main component has a purity greater than 90%, and the main component is solder alloy powder and / or metal element powder. The auxiliary component includes a variety of low-temperature volatilization reagents.

[0046] Specifically, after the eutectic slurry is used, the eutectic no longer uses friction to reduce the eutectic void rate, but uses a low vacuum bubble breaking method to reduce the eutectic void rate. Eutectic-specific solder sheets for each component are no longer required, which improves production flexibility. The auxiliary components are not easy to volatilize at room temperature, and the auxiliary components are easy to volatilize at 80℃ to 200℃. There is no residue after volatilization, and there is no corrosion to the solder powder and components.

[0047] The main components are metal powder and / or solder alloy powder with a melting point below 500°C.

[0048] The metal single substance powder and the solder alloy powder are both in the form of flakes or spheres, and the particle sizes of the metal single substance powder and the solder alloy powder are both in the range of 2400 to 500 meshes.

[0049] The main component powder is one or more of gold-tin powder, gold-germanium powder, tin-lead powder, indium-lead powder, tin-silver-copper powder or indium powder.

[0050] Specifically, the main component powder includes but is not limited to gold tin, gold germanium, tin lead, indium lead, tin silver copper, and indium powder. The main component powder has the characteristics of low oxidation degree and easy reduction under the action of reducing gas. The main component powder can be well dispersed in the reagent of the auxiliary component.

[0051] The auxiliary component is one or more of a flux, a thickener, a dispersant, a wetting agent, a thixotropic agent and a coupling agent.

[0052] Specifically, vacuum eutectic slurry consists of two parts, namely the main component and the auxiliary component. The main component is various solder alloy powders or metal element powders, which play a role in welding. The auxiliary components are a variety of low-temperature volatile reagents, including flux, thickener, dispersant, wetting agent, thixotropic agent and coupling agent. The auxiliary components are responsible for wetting or dispersing various solder powders to form slurry for pasting components, and do not participate in the final welding reaction.

[0053] The auxiliary components are one or more of terpineol, ethanol, ethylene glycol, propylene glycol, glycerol, nonylphenol, n-hexanoic acid and perfluorooctane.

[0054] Example 2

[0055] This embodiment provides a method for preparing a vacuum eutectic slurry of a low-temperature volatilization auxiliary component, which is used to prepare the above-mentioned vacuum eutectic slurry of a low-temperature volatilization auxiliary component, comprising the following steps:

[0056] S1. Select the main components and auxiliary components for preparing the slurry.

[0057] S11. The main component is gold-tin alloy, and the auxiliary components are propylene glycol, nonylphenol, hexanoic acid and perfluorooctanoic acid. The gold-tin alloy is prepared by a high-temperature and high-viscosity dispersion powder making method to prepare No. 8 gold-tin powder with low impurities and little oxidation, and the melting point is 280°C. A reducing agent or inert gas is added during the powder making process for protection to ensure that the prepared gold-tin powder meets the pulping process requirements;

[0058] S12. Gold-tin alloy, propylene glycol, nonylphenol, n-hexanoic acid and perfluorooctanoic acid are mixed in a mass ratio of 80﹕10﹕5:2.5﹕2.5. 40 g of gold-tin powder, 5 g of propylene glycol, 2.5 g of nonylphenol, 1.5 g of n-hexanoic acid and 1.5 g of perfluorooctanoic acid are weighed and then fully mixed. The slurry is stirred for 20 minutes to allow the auxiliary components to dissolve each other and the gold-tin powder to be fully dispersed in the slurry to prepare a eutectic slurry. The dynamic viscosity of the eutectic slurry is between 1800 and 2400 centipoise.

[0059] Example 3

[0060] This embodiment provides a method for using a vacuum eutectic slurry of a low-temperature volatilization auxiliary component, which is prepared using the above-mentioned method for preparing a low-temperature volatilization auxiliary component, and includes the following steps:

[0061] A1. Introduce the evenly stirred eutectic slurry into the glue cartridge, store it in a refrigerator at 5-8°C, install it on the automatic glue dispensing machine, and make glue dispensing calibration;

[0062] A2. Prepare the dispensing program, put the product on the workbench, and apply the eutectic slurry on the area where eutectic is required. The coating area is about 80% of the chip area.

[0063] A3. Take out the product coated with slurry, put it into the automatic placement machine, and place the components to be eutectic into the corresponding positions as required;

[0064] A4. Take out the product with components attached and put it into the vacuum eutectic furnace;

[0065] A5. Set the eutectic furnace heating curve. The first stage of the heating is responsible for volatilizing the auxiliary components of the slurry, the second stage of the heating is responsible for reducing the oxides with reducing gas, and the third stage of the heating is responsible for melting the solder to achieve welding;

[0066] like Figure 1 The heating curve is set as shown, with temperature T1 set to 150°C, T2 set to 170°C, T3 set to 240°C, and T4 set to 310°C. Formic acid is used as the reducing gas for the oxide during the process. The T1 temperature of the curve volatilizes the auxiliary components of the slurry, the T2 temperature reacts the tin oxide into formate, and the T3 temperature reduces the formate into tin. The T4 temperature melts the solder for welding;

[0067] Figure 1Explanation of the markings in the figure: 1 is the temperature curve, 2 is the volatilization of auxiliary components by heating, 3 is the extraction of volatilized auxiliary components, 4 is the filling of replacement nitrogen, 5 is the extraction of replacement gas, 6 is the filling of reducing gas such as formic acid, hydrogen or carbon monoxide, 7 is the reaction of reducing gas with oxide to form salt, 8 is the reduction of salt to metal, 9 is the extraction of large bubbles in the welding area, 10 is the vacuum breaking by filling with nitrogen, 11 is the filling of high-pressure nitrogen to compress small bubbles, 12 is the initial volatilization temperature, 13 is the middle reaction temperature one, 14 is the middle reaction temperature two, and 15 is the final melting welding temperature.

[0068] A6. After the first stage of heating, the volatilized gas of the auxiliary components and the oxygen in the air are extracted, and then nitrogen is filled and vacuumed to replace the residual gas, and finally protective or reducing gas is filled; in the second stage of heating, sufficient time should be left for the reducing gas to reduce the oxide; in the third stage of heating, low pressure is used to break the bubbles, and then positive pressure is filled to compress the bubbles that have not been broken, so as to reduce the eutectic void rate;

[0069] A7. Start the vacuum eutectic furnace. The eutectic furnace runs according to the designed curve. When the temperature reaches the melting point of the solder, the solder powder melts into liquid and connects together, filling the space between the components and the substrate to form a weld. At this time, there is an operation of first evacuating the vacuum and then filling it with positive pressure, which greatly reduces the void rate of the eutectic soldering.

[0070] A8. After the equipment is finished running, take out the product for void rate detection and quality inspection, and the process is completed.

[0071] Working principle:

[0072] When using the slurry, first use an automatic dispensing machine to apply the slurry, then use an automatic placement machine to paste the eutectic components, put them into a vacuum eutectic furnace, volatilize the auxiliary components, and finally melt and weld them under the action of various protective or reducing gases to achieve automatic eutectic. The difference between the use of slurry and conductive adhesive is that after the conductive adhesive is pasted, it enters a high-temperature oven for curing. After the vacuum welding slurry is pasted, it enters a vacuum eutectic furnace to first evaporate the auxiliary components, then remove the gas volatilized by the auxiliary components, and then melt and weld. The welding process requires gases such as hydrogen, formic acid or carbon monoxide to reduce the oxides, improve the wettability of the solder and reduce oxidation. In the final stage of solder melting, there is an operation of first vacuuming and then filling with positive pressure. The purpose is to first vacuumize to break the large bubbles, and then add positive pressure to reduce the bubbles that cannot be broken, thereby reducing the eutectic void rate.

[0073] The slurry has a certain viscosity and its usage is very similar to that of conductive glue. After dispensing and patching, the conductive glue enters a high-temperature oven for curing to achieve bonding. After dispensing and patching, the eutectic slurry enters a vacuum eutectic furnace to volatilize the auxiliary components first, and finally melts in the furnace to achieve welding. The dispensing and patching processes between the two are the same, but the curing and welding in the final stage are different. Equipment reuse is achieved to a large extent, saving production resources.

Claims

1. A vacuum eutectic slurry with a low-temperature volatilization auxiliary component, characterized in that: It comprises a main component and an auxiliary component. The purity of the main component is greater than 90%. The main component is solder alloy powder and / or metal element powder. The auxiliary component comprises a plurality of low-temperature volatilizing reagents.

2. The vacuum eutectic slurry of low-temperature volatilization auxiliary component according to claim 1, characterized in that: The main component is a metal powder and / or solder alloy powder having a melting point lower than 500°C.

3. The vacuum eutectic slurry of low-temperature volatilization auxiliary component according to claim 2, characterized in that: The metal single substance powder and the solder alloy powder are both in the form of flakes or spheres, and the particle sizes of the metal single substance powder and the solder alloy powder are both in the range of 2400 to 500 meshes.

4. The vacuum eutectic slurry of low-temperature volatilization auxiliary component according to claim 2, characterized in that: The main component powder is one or more of gold-tin powder, gold-germanium powder, tin-lead powder, indium-lead powder, tin-silver-copper powder or indium powder.

5. The vacuum eutectic slurry of low-temperature volatilization auxiliary component according to claim 4, characterized in that: The auxiliary component is one or more of a flux, a thickener, a dispersant, a wetting agent, a thixotropic agent and a coupling agent.

6. The vacuum eutectic slurry of low-temperature volatilization auxiliary component according to claim 5, characterized in that: The auxiliary component is one or more of terpineol, ethanol, ethylene glycol, propylene glycol, glycerol, nonylphenol, n-hexanoic acid and perfluorooctane.

7. A method for preparing a vacuum eutectic slurry of a low-temperature volatilization auxiliary component, used for preparing a vacuum eutectic slurry of a low-temperature volatilization auxiliary component according to any one of claims 1 to 6, characterized in that: The steps include: S1. Selecting the main components and auxiliary components for preparing the slurry; S11, the main component is gold-tin alloy, and the auxiliary components are propylene glycol, nonylphenol, hexanoic acid and perfluorooctanoic acid; S12. Determine the proportion of each component of gold-tin alloy, propylene glycol, nonylphenol, hexanoic acid and perfluorooctanoic acid, and prepare a eutectic slurry by fully stirring. The dynamic viscosity of the eutectic slurry is between 1800 and 2400 centipoise.

8. The method for preparing a vacuum eutectic slurry of a low-temperature volatilization auxiliary component according to claim 7, characterized in that: In step S11, the gold-tin alloy is powdered by a high-temperature and high-viscosity dispersion liquid to prepare No. 8 gold-tin powder with low impurities and little oxidation, and a melting point of 280°C. A reducing agent or inert gas is added during the powdering process for protection to ensure that the prepared gold-tin powder meets the pulping process requirements.

9. The method for preparing a vacuum eutectic slurry of a low-temperature volatilization auxiliary component according to claim 7, characterized in that: In step S12, gold-tin alloy, propylene glycol, nonylphenol, hexanoic acid and perfluorooctanoic acid are mixed in a mass ratio of 80﹕10﹕5:2.5﹕2.5, and 40 grams of gold-tin powder, 5 grams of propylene glycol, 2.5 grams of nonylphenol, 1.5 grams of hexanoic acid and 1.5 grams of perfluorooctanoic acid are weighed and then thoroughly mixed.

10. A method for using a vacuum eutectic slurry of a low-temperature volatilization auxiliary component, wherein the vacuum eutectic slurry is prepared using the method for preparing a vacuum eutectic slurry of a low-temperature volatilization auxiliary component according to any one of claims 7 to 9, characterized in that: The steps include: A1. Introduce the evenly stirred eutectic slurry into the glue cartridge, store it in a refrigerator at 5-8°C, install it on the automatic glue dispensing machine, and make glue dispensing calibration; A2. Prepare the dispensing program, place the product on the workbench, and apply the eutectic slurry on the area where eutectic is required; A3. Take out the product coated with slurry, put it into the automatic placement machine, and place the components to be eutectic into the corresponding positions as required; A4. Take out the product with components attached and put it into the vacuum eutectic furnace; A5. Set the eutectic furnace heating curve. The first stage of the heating is responsible for volatilizing the auxiliary components of the slurry, the second stage of the heating is responsible for reducing the oxides with reducing gas, and the third stage of the heating is responsible for melting the solder to achieve welding; A6. After the first stage of heating, the volatilized gas of the auxiliary components and the oxygen in the air are extracted, and then nitrogen is filled and vacuumed to replace the residual gas, and finally protective or reducing gas is filled; in the second stage of heating, sufficient time should be left for the reducing gas to reduce the oxide; in the third stage of heating, low pressure is used to break the bubbles, and then positive pressure is filled to compress the bubbles that have not been broken, so as to reduce the eutectic void rate; A7. Start the vacuum eutectic furnace. The eutectic furnace runs according to the designed curve. When the temperature reaches the melting point of the solder, the solder powder melts into liquid and is connected together, filling between the components and the substrate to form a weld. At this time, there is an operation of first vacuuming and then filling with positive pressure, which greatly reduces the void rate of the eutectic soldering. A8. After the equipment is finished running, take out the product for void rate detection and quality inspection, and the process is completed.

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