Airflow breaking mechanism

Abstract

The application relates to a nanoscale lead-free low-melting-point glass powder and a preparation method thereof, characterized in that the glass component comprises Bi2O3 40-80%, B2O3 12-30%, and ZnO 8-25% in percentage by mass, the glass component further comprises a mixture of one or more than one of P2O5, V2O5, BaO, CuO, Al2O3, MgO, Na2O, Li2O, SiO2, K2O and CaO in percentage by mass and in any ratio, the weighed glass mixture is fully mixed, high-temperature melting, water quenching, drying, rough breaking, high-energy airflow breaking, spherical shaping and precision grading are carried out, and a nanoscale lead-free low-melting-point glass powder with high purity, small particle size, uniform particle size distribution, good fluidity and good dispersibility can be obtained and applied to the field of electronic packaging.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of glass powder preparation, and particularly relates to a nano-scale lead-free low-melting-point glass powder and a preparation method thereof. BACKGROUND

[0002] Sealing glass powder refers to special glass which can realize the mutual connection and airtight packaging of semiconductors, glass, ceramics and metals by heating and sealing the same or different materials together. Sealing glass powder is a kind of special glass with the characteristics of low sealing temperature, high sealing strength, good sealing effect and high stability, and is a kind of inorganic non-metallic material with excellent performance. Sealing mainly realizes three functions: mechanical support, environmental protection and electrical connection, and specifically includes: 1. bonding between substrates, such as bonding a silicon wafer to a carrier wafer made of glass, quartz, sapphire, ceramic and metal materials; 2. fixing micro components to a carrier substrate, such as fixing a silicon die to a substrate made of glass or ceramic; 3. connecting input and output leads of a micro device converter and conductive wires. The advantage of glass powder sealing lies in that the required packaging temperature is low, the bonding strength is high, and at the same time, there is no special requirement for the surface of the packaging substrate; the thermal expansion coefficient of the sealing glass is matched with silicon, the sealing effect is good, the process is simple, the production efficiency is high, and the low-cost and high-reliability wafer-level packaging can be realized. Therefore, under the condition of meeting stability and reliability, glass powder packaging has a wide application in wafer-level packaging, and the specific application device field includes pressure sensors, optical sensors, MEMS microphones, micro motors, gyroscopes and the like.

[0003] Because the device volume is very small, the size is only a few millimeters, the packaging difficulty is big, must adopt the special technology and the material to carry on the packaging. Moreover, the packaging cost is high, its packaging cost accounts for the whole device cost 50%~80% around, far higher than the cost of ordinary electronic device packaging. Foreign only the United States Ferro company, Japan NEG company, the United States Diemat company etc. A few companies have such products sales, like the United States Ferro company's trade mark is 11-036 Product sealing temperature reaches 450 ℃, thermal expansion coefficient is 90 × 10-7 / ℃ (20~300 ℃), and the 26 × 10-7 / ℃ of silicon and the 33 × 10-7 / ℃ of Pyrex glass are relatively close (the matching of thermal expansion coefficient is more favorable to the realization of sealing performance), and the sealing temperature and sealing strength are suitable, so the use amount is the largest;The trade mark of the product of the United States Diemat company is DM2700, and the sealing temperature is 320~370 ℃, and the thermal expansion coefficient is 77 × 10-7 / ℃, the sealing temperature is low, but the sealing strength is small;The thermal expansion coefficient of PbO-SiO2-Al2O3 type sealing glass powder of Japan NEG is as low as 40 × 10-7 / ℃, but the sealing temperature is higher than 500 ℃. It can be seen that the currently marketed microelectronic low-melting sealing glass powder is mostly lead-containing, and the particle size is mostly micron level, and the sealing effect is poor, and the nano-level lead-free low-melting sealing has become the development direction of the world electronic industry. SUMMARY

[0004] The purpose of the present application is to make up for the deficiency of the prior art that the low-melting glass powder has a coarse particle size and poor sealing effect, and to provide a nano-level low-melting glass powder and a preparation method thereof. The present application controls the formula: Bi2O3-B2O3-ZnO system glass, which further contains one or more of P2O5, V2O5, BaO, CuO, Al2O3, MgO, Na2O, Li2O, SiO2, K2O and CaO in any ratio, which together improve the low-temperature properties, crystallization properties, thermal expansion, sealing temperature and chemical stability of the glass. The melted glass is water-quenched, dried, coarsely broken, high-energy airflow broken and precisely graded. The nano glass powder is prepared by the high-energy airflow method, which has the advantages of short process and high yield compared with the traditional chemical preparation process. The nano-level low-melting glass powder with good dispersibility, good fluidity and good sealing effect is prepared.

[0005] In order to achieve the above purpose, a nano-level lead-free low-melting glass powder is used, which comprises the following raw materials in mass percentage:

[0006] The glass composition comprises 40-80% Bi2O3, 12-30% B2O3, and 8-25% ZnO, and also contains, by mass percentage, one or more of P2O5, V2O5, BaO, CuO, Al2O3, MgO, Na2O, Li2O, SiO2, K2O, and CaO in any proportion.

[0007] As a further optimization of the above solution, the nanoscale low-melting-point glass powder comprises the following raw materials by mass percentage:

[0008] Bi2O3 42%, B2O3 19%, ZnO 20%, P2O5 1%, V2O5 2%, BaO 5%, CuO 4%, Al2O3 1.5%, MgO 0.5%, Na2O 2%, Li2O 1%, SiO2 1%, K2O 0.5%, CaO 0.5%.

[0009] As a further optimization of the above solution, the nano-glass powder comprises the following raw materials in weight percentages:

[0010] Bi2O352%, B2O314%, ZnO 15%, P2O51%, V2O52%, BaO 5%, CuO 4%, Al2O3 1.5% , MgO0.5%, Na2O 2%, Li2O 1%, SiO21%, K2O 0.5%, CaO 0.5%.

[0011] As a further optimization of the above solution, the nano-glass powder comprises the following raw materials in weight percentages:

[0012] Bi2O3 62%, B2O3 13%, ZnO 10%, P2O5 1%, V2O5 2%, BaO 3%, CuO 2%, Al2O3 1.5%, MgO 0.5%, Na2O 2%, Li2O 1%, SiO2 1%, K2O 0.5%, CaO 0.5%.

[0013] A method for preparing nanoscale lead-free low-melting-point glass powder includes the following steps:

[0014] (1) Weigh each raw material according to the ratio of a nano-level lead-free low melting point glass powder, and melt it according to the following steps: heat from room temperature to 700~800℃ for 1~3 hours, heat from 700~800℃ to 1100~1300℃ for 1~2 hours, and keep it at that temperature for 1~3 hours.

[0015] (2) the melted glass is water-quenched, dried, roughly broken, high-energy airflow broken by airflow breaking mechanism, spheroidized, and precisely graded;

[0016] (3) the sealing glass powder is generally prepared into electronic paste before use, preferably, the content of nanoscale low-melting-point glass powder is 88wt%, and the content of organic carrier is 12wt%, and the suitable nanoscale low-melting-point electronic paste for sealing is prepared.

[0017] As further optimization of the above scheme, in step (3), the organic carrier formula is as follows: 75wt% of terpineol mixed solvent, 4wt% of ethyl cellulose, 8wt% of hydrogenated castor oil, 6wt% of KH570, and 2wt% of n-butanol.

[0018] In the application, Bi2O3, BaO and CuO are used to reduce the softening point of the glass, moderately give fluidity, and adjust the thermal expansion coefficient to a suitable range.

[0019] B2O3 is a forming oxide of the glass, can play a fluxing role, reduce the melting temperature of the glass, accelerate the melting and fining of the glass, and when less than 8%, the effect is poor, and can inhibit the excessive rise of the thermal expansion coefficient of the glass, and when sealing, can give the glass powder with moderate fluidity, improve the thermal stability and chemical stability of the glass, and when more than 30%, the stability and acid resistance of the glass will be reduced, and more preferably, 10-20%.

[0020] ZnO is used to reduce the softening point of the glass and adjust the thermal expansion coefficient to a suitable range, and ensure the acid resistance of the glass powder, and when more than 20%, the glass will become unstable and prone to devitrification, and more preferably, 7-12%.

[0021] SiO2 is the main component of forming glass silicon-oxygen tetrahedron and connecting to constitute the glass network structure, can reduce the thermal expansion coefficient of the glass, improve the thermal shock stability, chemical stability, hardness and mechanical strength of the glass, and is a necessary component to obtain high acid resistance, and when the content of SiO2 is too large, the melting temperature of the glass will be increased, and crystallization may be caused.

[0022] Al2O3 can reduce the crystallization tendency of the glass, improve the chemical stability, thermal stability, mechanical strength and hardness of the glass, and in the case that the content of alkali metal in the glass is relatively high and the network fracture is serious, the intermediate oxide (such as Al2O3) is added to reconnect the fractured silicon-oxygen tetrahedron and make the structure of the glass more stable.

[0023] Li2O, Na2O and K2O can improve the melting property when the glass is melted, and reduce the softening point of the glass, and therefore, at least one of them is preferably in the range of 0-6% in the glass.

[0024] As a further optimization of the above solution, the airflow breaking mechanism is an airflow plug, which has a crushing chamber. A plurality of air nozzles are evenly spaced on the outer inner wall of the crushing chamber, wherein:

[0025] The inner cavity of the nozzle is provided with a flow guide channel and a flow guide component along the air blowing direction. The flow guide component is provided with a stop section, an extension section and an air blowing section in sequence along the gas discharge direction. The flow guide channel is provided with a flow guide section and a buffer section in sequence along the air blowing direction. The stop section and the air blowing section of the flow guide section are pressed and fixed with a sealing gasket arranged parallel to the air blowing direction. An elastic component that moves with the extension section is sleeved on the outside of the extension section, and one part of the elastic component abuts against the air blowing end of the buffer section so that the elastic component can move and extend when it moves outside the extension section.

[0026] The arrangement of this nozzle structure allows the guide component to compress the sealing gasket during the exhaust process, greatly improving the tightness of the sealing gasket, reducing gas leakage, and enhancing the nozzle's air jet performance.

[0027] As a further optimization of the above scheme, the above-mentioned guide section is provided with an inlet section and a constriction section along the straight direction. The diameter of the constriction section decreases along the airflow direction. The throat is arranged in the abutment section, and the diffuser is arranged in the extension section and connected to the air blowing section. The throat connects the constriction section and the diffuser section so that the above-mentioned inlet section, constriction section, throat and diffuser section form a Venturi tube structure.

[0028] The original nozzle inner cavity structure was changed to a venturi tube structure, which reduces fluid resistance, lowers energy consumption, improves stability, provides a smooth pressure difference, and is less prone to clogging with long-term use, ensuring a stable blowing effect.

[0029] As a further optimization of the above solution, the sealing gasket is designed in the contraction part, that is, in this embodiment, the sealing gasket is designed in the contraction part where the airflow pressure is the greatest, so as to ensure that the sealing gasket is squeezed in the part with the greatest pressure, thereby further improving the tightness of the sealing gasket, reducing gas leakage, and improving the jetting effect of the nozzle.

[0030] As a further optimization of the above solution, a balance plate is also fitted on the above-mentioned guide section. Balance cavities are provided on both sides of the guide channel. The balance arm is designed in the balance cavity. One end of the balance arm passes through the balance cavity and is hinged to one end of the balance plate. After the balance plate is tilted, the other end of one of the balance arms abuts against the inner wall of the balance cavity, so as to restrict the movement of the guide section along the direction of parallel airflow, avoid the guide component from deviating during the extrusion process, reduce the phenomenon of airflow path deviation, and ensure the airflow jet effect.

[0031] The present invention provides a nanoscale lead-free low-melting-point glass powder and its preparation method, which have the following beneficial effects:

[0032] 1. The present invention has a thermal expansion coefficient of about 90×10-7 / ℃ (20~300 ℃). The matching thermal expansion coefficient is more conducive to the realization of sealing performance, and the nanoscale glass powder has the properties of low sealing temperature (<460℃), high sealing strength, good sealing effect and high stability.

[0033] 2. This invention adjusts the glass formulation by adding certain amounts of P2O5, V2O5, BaO, CuO, Al2O3, MgO, Na2O, Li2O, SiO2, K2O, and CaO. The combined effect of these raw materials lowers the softening point of the glass and adjusts the coefficient of thermal expansion to a suitable range, reducing the sealing temperature from around 550℃ to around 450℃. Furthermore, this patent involves drying, coarsely crushing, high-energy airflow breaking, spherical shaping, and precise grading of the water-quenched glass fragments, increasing the fluidity of the glass powder. This facilitates the removal of organic matter such as binders, reducing the likelihood of cracking during sealing and improving the sealing performance of MEMS devices.

[0034] 3. In the preparation method of nano-level lead-free low-melting-point glass powder, a special airflow breaking mechanism is adopted, which has a Venturi tube structure with a compression sealing gasket. Under the premise of ensuring smooth airflow, the sealing gasket is effectively compressed, reducing the airflow overflow effect while ensuring that the airflow path does not deviate, and increasing the airflow jetting effect.

[0035] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope as a result, and the embodiments of the present invention include many changes, modifications and equivalents. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the airflow plug in this invention;

[0037] Figure 2 This is a schematic diagram of the pulverizing chamber in this invention;

[0038] Figure 3 This is a schematic diagram of the air nozzle structure in this invention;

[0039] Figure 4 This is a schematic diagram of the flow guiding channel in this invention;

[0040] Figure 5 This is a schematic diagram of the flow guide in this invention.

[0041] In the figure: 1, air flow plug; 2, crushing cavity; 3, air nozzle; 4, flow guide channel; 41, flow guide section; 411, inlet portion; 412, contraction portion; 42, buffer section; 5, flow guide piece; 51, abutting section; 511, throat; 52, elongated section; 53, air blowing section; 6, sealing gasket; 7, elastic member; 8, diffusion portion; 9, balance plate; 91, balance cavity; 92, balance arm. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions and advantages of the present application clearer, further detailed description will be given below with reference to the accompanying drawings and examples. However, it should be understood that the specific examples described herein are only used to explain the present application and are not used to limit the scope of the present application.

[0043] It should be noted that when an element is referred to as "provided on" or "provided with" another element, it can be directly on the other element or there can be a middle element, and when an element is referred to as "connected to" or "connected with" another element, it can be directly connected to the other element or there can be a middle element, and "fixedly connected" means fixed connection, and there are many ways of fixed connection, which are not the protection scope of the present application, and the terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only implementation.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs, and the terms used herein in the specification are only for the purpose of describing specific embodiments and are not intended to limit the present application, and the term "and / or" used herein includes any and all combinations of one or more related listed items;

[0045] First embodiment:

[0046] The present application provides a technical solution: a preparation method of nanoscale lead-free low-melting point glass powder, specifically comprising the following steps:

[0047] (1) The raw materials are weighed according to the following mass percentages: Bi2O362%, B2O313%, ZnO 10%, P2O51%, V2O52%, BaO 3%, CuO 2%, Al2O31.5% , MgO 0.5%, Na2O 2%, Li2O 1%, SiO21%, K2O 0.5%, CaO 0.5%;

[0048] (2) The raw materials are weighed according to the above ratio, and melting is carried out according to the following steps: from room temperature to 700-800 DEG C, for 1-3 hours, from 700-800 DEG C to 1100-1300 DEG C, for 1-2 hours, and holding for 1-3 hours; the melted glass is water quenched, dried, coarsely broken, high-energy air flow broken (the broken glass enters the grinding cavity and is fluidized by high-speed airflow, and mutual collision is carried out near the focal point of the airflow intersection area, the material is crushed by internal particle collision, and the airflow at the edge of the airflow mill is also sheared to crush the particles, the grinding airflow then passes through the classification wheel at the upper end, the fine particles meeting the requirements are separated from the classification wheel and leave the mill, and the coarse particles re-enter the grinding cavity to collide and grind until the particles meet the specified particle size requirement, and the particle size can be adjusted by adjusting the air flow rate, air pressure in the grinding cavity, and classification wheel speed; ), spheroidization shaping (dry stirring bead grinding is used, and the glass powder broken by air flow is ground, dispersed and shaped using grinding beads as a medium, and air is introduced at the bottom, so that the dispersed and shaped particles are then passed through the classification wheel at the upper end and are collected in the filter; ), precision classification; the sealing glass powder is generally prepared into electronic paste before use, and preferably, the content of nanoscale low-melting point glass powder is 88wt%, and the content of organic carrier is 12wt%, and the electronic paste prepared from the nanoscale low-melting point sealing glass powder is: the organic carrier formula is 75wt% of mixed solvent of terpineol, 4wt% of ethyl fiber, 8wt% of hydrogenated castor oil, 6wt% of KH570, and 2wt% of n-butanol.

[0049] Second embodiment:

[0050] The application provides a technical scheme: a preparation method of nanoscale lead-free low-melting point glass powder, specifically comprising the following steps:

[0051] (1) The raw materials are weighed according to the following mass percentage: Bi2O362%, B2O313%, ZnO 10%, P2O51%, V2O52%, BaO 3%, CuO2%, Al2O31.5% , MgO 0.5%, Na2O 2%, Li2O 1%, SiO21%, K2O 0.5%, and CaO 0.5%;

[0052] (2) The raw materials are weighed according to the above ratio, and melting is carried out according to the following steps: from room temperature to 700-800 DEG C, for 1-3 hours, from 700-800 DEG C to 1100-1300 DEG C, for 1-2 hours, and keep for 1-3 hours; the melted glass is water quenched, dried, roughly broken, air flow broken, and wet stirring is carried out by adding water to the 50% solid content powder, and then drying, to obtain the nano lead-free glass powder; the sealing glass powder generally needs to be prepared into electronic paste before use, preferably the nano low-melting point glass powder content is 88wt%, and the organic carrier content is 12wt%, to prepare the suitable nano low-melting point electronic paste for packaging: the organic carrier formula is 75wt% of terpineol mixed solvent, 4wt% of ethyl fiber, 8wt% of hydrogenated castor oil, 6wt% of KH570, and 2wt% of n-butanol.

[0053] The comparison is as follows:

[0054] (1) The raw materials are weighed according to the following mass percentage: Bi2O362%, B2O313%, ZnO 10%, P2O51%, V2O52%, BaO 3%, CuO2%, Al2O31.5% , MgO 0.5%, Na2O 2%, Li2O 1%, SiO21%, K2O 0.5%, CaO 0.5%;

[0055] (2) The raw materials are weighed according to the above ratio, and melting is carried out according to the following steps: from room temperature to 700-800 DEG C, for 1-3 hours, from 700-800 DEG C to 1100-1300 DEG C, for 1-2 hours, and keep for 1-3 hours; the melted glass is water quenched, dried, roughly broken, air flow broken, and wet stirring is carried out by adding water to the 50% solid content powder, and then drying, to obtain the nano lead-free glass powder; the sealing glass powder generally needs to be prepared into electronic paste before use, preferably the nano low-melting point glass powder content is 88wt%, and the organic carrier content is 12wt%, to prepare the suitable nano low-melting point electronic paste for packaging: the organic carrier formula is 75wt% of terpineol mixed solvent, 4wt% of ethyl fiber, 8wt% of hydrogenated castor oil, 6wt% of KH570, and 2wt% of n-butanol.

[0056] The effects of the embodiment of the application are shown in the following table

[0057]

[0058] Third embodiment:

[0059] As Figures 1-5 shown, the application provides a technical solution: a preparation method of nano lead-free low-melting point glass powder, specifically comprising the following steps:

[0060] (1) According to the proportioning of a nano-scale lead-free low-melting point glass powder, each raw material is weighed and melted according to the following steps: from room temperature to 700-800 DEG C, 1-3 hours, from 700-800 DEG C to 1100-1300 DEG C, 1-2 hours, and 1-3 hours of holding;

[0061] (2) The melted glass is water-quenched, dried, roughly broken, high-energy airflow broken by airflow breaking mechanism, spheroidized, and precisely graded;

[0062] (3) The sealing glass powder generally needs to be prepared into electronic paste before use, preferably a nano-scale low-melting point glass powder content of 88wt%, and an organic carrier content of 12wt%, to prepare a suitable nano-scale low-melting point electronic paste for packaging.

[0063] The airflow breaking mechanism is an airflow plug 1, which is provided with a crushing cavity 2, and a plurality of air nozzles 3 are arranged at equal intervals on the outer wall of the crushing cavity 2, wherein:

[0064] The inner cavity of the air nozzle 3 is provided with a flow guide channel 4 and a flow guide piece 5 in the air blowing direction, and the flow guide piece 5 is sequentially provided with an abutting section 51, an elongated section 52 and an air blowing section 53 in the air blowing direction. The abutting section 51 and the air blowing section 53 of the flow guide section 41 are fixedly provided with a sealing gasket 6 arranged in parallel to the air blowing direction, the elongated section 52 is provided with an elastic member 7 which moves with the elongated section 52 and one end of the elastic member 7 abuts against the air blowing end of the buffer section 42 so that the elastic member 7 expands and contracts, the flow guide section 41 is provided with an inlet portion 411 and a contraction portion 412 in a straight line direction, the diameter of the contraction portion 412 decreases in the airflow direction, the throat 511 is arranged in the abutting section 51, the diffusion portion 8 is arranged in the elongated section 52 and communicates with the air blowing section 53, the throat 511 penetrates the contraction portion 412 and the diffusion portion 8 so that the inlet portion 411, the contraction portion 412, the throat 511 and the diffusion portion 8 form a Venturi structure, the sealing gasket 6 is designed in the contraction portion 412, and the flow guide section 41 is further provided with a balance plate 9, both sides of the flow guide channel 4 are provided with a balance cavity 91, and a balance arm 92 is designed in the balance cavity 91. One end of the balance arm 92 penetrates the balance cavity 91 and is hingedly connected to one end of the balance plate 9, and the other end of one of the balance arms 92 abuts against the inner wall of the balance cavity 91 when the balance plate 9 is inclined.

[0065] The above structure has a Venturi structure for extruding the sealing gasket 6, which effectively extrudes the sealing gasket 6 under the premise of ensuring smooth airflow, reduces the overflow effect of the airflow, ensures that the airflow path does not deviate, and increases the airflow injection effect.

[0066] The above merely provides the preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement or improvement made in the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. An airflow breaking mechanism, characterized in that: The airflow breaking mechanism is an airflow plug, which has a crushing chamber. A plurality of air nozzles are evenly spaced on the inner wall of the crushing chamber. The inner cavity of the nozzle is provided with a flow guide channel and a flow guide component along the air blowing direction. The flow guide component is provided with a contact section, an extension section and an air blowing section in sequence along the gas discharge direction. The flow guide channel is provided with a flow guide section and a buffer section in sequence along the air blowing direction. The contact section and the air blowing section of the flow guide section are pressed and fixed with a sealing gasket arranged parallel to the air blowing direction. An elastic component that moves with the extension section is sleeved on the outside of the extension section, and one end of the elastic component abuts against the air blowing section of the buffer section so that the elastic component can move and extend when it moves outside the extension section. The aforementioned guide section is provided with an inlet section and a constriction section along the straight direction. The diameter of the constriction section decreases along the airflow direction. The throat is arranged in the contact section, and the diffuser is arranged in the extension section and connected to the air blowing section. The throat connects the constriction section and the diffuser section so that the aforementioned inlet section, constriction section, throat and diffuser section form a Venturi tube structure.

2. The airflow breaking mechanism according to claim 1, characterized in that: The aforementioned sealing gasket is designed in the shrinkage section.

3. The airflow breaking mechanism according to claim 2, characterized in that: The aforementioned guide section is also fitted with a balance plate. Both sides of the guide channel are provided with balance cavities. The balance arm is designed inside the balance cavity. One end of the balance arm passes through the balance cavity and is hinged to one end of the balance plate. After the balance plate is tilted, the other end of one of the balance arms abuts against the inner wall of the balance cavity.

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