MEMS (Micro Electro Mechanical System) semiconductor nano glass powder as well as preparation method and application thereof

Abstract

The invention discloses MEMS semiconductor nano glass powder as well as a preparation method and application thereof, and belongs to the technical field of nano glass powder. According to the prepared glass powder, through raw material selection and fine raw material proportioning, the performance of each material is fully exerted, side effects caused by excessive use of each raw material are greatly weakened, and compared with traditional backflow glass powder, the glass powder is low in backflow temperature, saves energy, is beneficial to device safety and is suitable for large-scale production. The service life of the MEMS semiconductor device is prolonged; according to the method, the nano glass powder is prepared by directly utilizing the dry-method high-temperature steam flow, the particle size distribution is narrow, the dispersity is high, the backflow effect is good, the practical application of the nano glass powder in the field of MEMS semiconductor packaging is improved, and in conclusion, the method has important application value in the technical field of the nano glass powder.

Description

Technical Field

[0004] The present invention belongs to the technical field of nano glass powder, and in particular, relates to a MEMS semiconductor nano glass powder and a preparation method and application thereof. Background Art

[0005] MEMS (Micro-Electro-Mechanical Systems) is a micro device that integrates micro structures, micro sensors, micro actuators, signal processing and control circuits, interfaces, communications and power supplies on one or more chips. Specific application areas include semiconductor chips, sensors, accelerometers, resonators, gyroscopes, etc. With the rapid iteration and upgrading of electronic products, MEMS has higher and higher requirements for the airtightness and reliability of sealing products, and has also put forward higher requirements for sealing glass powder.

[0006] Wafer-level packaging is the cutting-edge trend and research focus of MEMS packaging technology. First, the MEMS sensitive unit is manufactured on the silicon wafer, and then the wafer with the cap and the sensitive unit is bonded, and finally cut into independent MEMS sensors. Before cutting, the entire silicon wafer is vacuum-sealed once, which not only shortens the packaging time and reduces the cost, but also facilitates mass production. During the bonding process, the cap provides mechanical protection to prevent high temperature from damaging the MEMS or circuit. Cap packaging is a common method to achieve wafer-level packaging. It ensures that the movable parts have enough movement space, and the cap is tightly combined with the substrate to meet the vacuum requirements in the cavity. Electrical signals are usually led out through vertical interconnection, that is, electrical signals are led out vertically, which supports three-dimensional chip stacking, shortens the transmission distance of electrical signals, and reduces signal interference. Vertical interconnection technology includes glass vertical interconnection (Through Glass Via-TGV) and silicon vertical interconnection (Through Silicon Via-TSV). Among them, TGV is more widely used due to its small parasitic capacitance, good thermal insulation and simple bonding process (mainly using anodic bonding). Glass not only has good insulation properties, but also has a good thermal matching coefficient with silicon, which effectively avoids the problem of device failure caused by excessive thermal stress after bonding. The biggest challenge of TGV technology lies in the design of through-holes, and the glass reflow process solves the problem of etching through-holes on glass. The traditional TGV process includes etching a microcavity on a silicon wafer, then anodically bonding the silicon wafer to the glass, filling the microcavity with glass by heating, and finally mechanical chemical polishing to form a TGV cap. However, the main disadvantages of the existing glass reflow process include: first, during anodizing, the surface roughness of glass and silicon is required to be high, and the bonding environment requires a high vacuum degree; the chemical properties of the glass surface will change after bonding; second, when the glass is heated and reflowed, there are problems such as high temperature, long time, easy formation of crystals, insufficient filling of the microcavity edge, easy formation of cavities inside, filling speed slows down as the cavity is reduced, and filling width is usually not less than 100 microns and the cavity with a sidewall angle of less than 90 degrees is difficult to fill; third, there are problems such as long polishing time and high polishing cost during polishing. Summary of the invention

[0007] The purpose of the present invention is to overcome the defects of the prior art and provide a MEMS semiconductor nano glass powder and a preparation method and application thereof.

[0008] The purpose of the present invention can be achieved through the following technical solutions:

[0009] A MEMS semiconductor nano glass powder includes the following raw materials in molar percentage: Bi2O3: 20-40%, TeO2: 20-40%, SiO2: 15-30%, B2O3: 1-15%, Al2O3: 1-15%, V2O5: 1-15%, Li2O: 0-10%, Na2O: 0-15%, K2O: 0-10%, MgO: 0-10%, CaO: 0-10%, SrO: 0-5%, BaO: 0-5%, MnO: 0-10%, Co2O3: 0-10%, Fe2O3: 0-10%, Zr2WO4(PO4)2: 1-10%.

[0010] Furthermore, the molar ratio of the raw materials satisfies the following conditions: 70%≤(Bi2O3+TeO2+SiO2)≤80%; 5%≤(MnO+Co2O3+Fe2O3)≤10%.

[0011] Furthermore, the particle size distribution D50 of the Zr2WO4(PO4)2 is less than 50 nm.

[0012] Further, as a preferred technical solution of the present invention, a MEMS semiconductor nanoglass powder includes the following raw materials in molar percentage: Bi2O3: 20-35%, TeO2: 25-35%, SiO2: 15-25%, B2O3: 5-15%, Al2O3: 3-10%, V2O5: 5-15%, Li2O: 1-5%, Na2O: 1-10%, K2O: 1-5%, MgO: 1-8%, CaO: 1-5%, SrO: 2-5%, BaO: 1-5%, MnO: 2-8%, Co2O3: 1-8%, Fe2O3: 2-8%, Zr2WO4(PO4)2: 3-10%.

[0013] A method for preparing MEMS semiconductor nano glass powder comprises the following steps:

[0014] Step S1, preparing a mixture: adding the raw materials except Zr2WO4(PO4)2 into a mixer of zirconium balls, mixing for 1-3 hours, and fully mixing to obtain a mixture;

[0015] Step S2, melting: put a crucible in a high-temperature electric furnace, add the mixture obtained in step S1, gradually increase the temperature to 1000-1400°C according to the step temperature, then add Zr2WO4(PO4)2 and stir evenly, and keep the temperature for 30-150 minutes to obtain a clear glass liquid;

[0016] Step S3, crushing and grinding: the clarified glass liquid obtained in step S2 is quenched in deionized water, taken out, dried and crushed, and then finely ground to nanometer particle size using a high-temperature steam jet mill to obtain MEMS semiconductor nano glass powder;

[0017] Step S4, preparing slurry: mixing and stirring the nano glass powder obtained in step S3, the solvent and the dispersant to form a paste, thereby obtaining glass powder slurry;

[0018] Step S5, glass powder reflow: scrape the glass powder slurry obtained in step S4 into the silicon microcavity, and then perform hot melt reflow on the nano glass powder. When the temperature reaches 600-700°C, keep it warm for 2-4 hours. After the hot melt reflow is completed, cool it down and then naturally cool it to room temperature to obtain reflux glass for MEMS semiconductor devices.

[0019] Furthermore, in step S3, the steam temperature of the high-temperature steam jet mill is 200-300° C., and the milling line speed is 800-1200 m / s.

[0020] Furthermore, the solvent in step S4 is one or more of ethylene glycol, triethanolamine, ethyl acetate, acetone and xylene.

[0021] Furthermore, the dispersant in step S4 is one or more of sodium silicate, Tween series, sodium dodecyl sulfate, and acrylate.

[0022] Furthermore, the mass ratio of the nano glass powder, the solvent and the dispersant in step S4 is 100:25:0.5.

[0023] Furthermore, in step S5, the heating rate of the hot melt reflow is 10-20°C / min; the atmosphere of the hot melt reflow is one of nitrogen and helium.

[0024] Furthermore, the temperature is lowered to 300° C. at a rate of 2-4° C. / min in step S5.

[0025] Adding Bi2O3 to the raw materials as a glass network-forming oxide gives the glass powder excellent chemical stability and reduces the melting temperature of the glass powder;

[0026] TeO2 added to the raw materials is also a glass network-forming oxide. The structural units in the glass powder are mainly tetracoordinated [TeO4] and tricoordinated [TeO3], which exist in a Te-O-Te chain structure or a more complex fabric network structure, which improves the mechanical strength of the glass powder.

[0027] Adding SiO2 to the raw materials is an important glass network former oxide, which forms the skeleton structure of glass, reduces the thermal expansion coefficient of glass powder, and improves the mechanical strength of glass powder;

[0028] Adding B2O3 to the raw materials as a glass network generator oxide is beneficial to improving the fusibility of glass powder and reducing the viscosity of glass powder;

[0029] Adding Al2O3 to the raw materials is a glass network intermediate oxide. Aluminum forms aluminum-oxygen tetrahedron in the glass, which plays a role in improving and strengthening the low-melting-point glass structure, and also reduces the crystallization tendency of the glass powder and improves a series of properties of the glass powder;

[0030] Li2O, Na2O and K2O are added to the raw materials as alkali metal oxides, which are the external oxides of the glass network. The three alkali metal oxides are added at the same time to form a mixed alkali effect, which improves the thermal and mechanical properties of the glass powder.

[0031] MgO, CaO, SrO and BaO added to the raw materials are alkaline earth metal oxides and do not participate in the network structure, but are network exogenous bodies. Among them, MgO and CaO are beneficial to improving the stability of glass powder, and SrO and BaO are beneficial to reducing the softening point of glass powder, improving the fluidity of glass powder in low temperature areas, and improving the production conditions and crystallization properties of glass powder, and enhancing the hardness and corrosion resistance of glass powder.

[0032] V2O5, MnO, Co2O3, and Fe2O3 added to the raw materials can work together and, through appropriate proportions, can significantly reduce the thermal expansion coefficient of glass powder;

[0033] The Zr2WO4(PO4)2 added to the raw materials is introduced using nano-scale raw materials, has nano-characteristics in terms of small size effect, surface effect, interface effect, etc., has a short melting time, and is randomly distributed inside the glass powder, which is beneficial to improving the mechanical strength and thermal stability of the glass powder.

[0034] Beneficial effects of the present invention:

[0035] 1. The glass powder prepared by the present invention makes full use of the performance of each material through the selection of raw materials and the fine raw material ratio, and greatly reduces the side effects caused by excessive use of each raw material. Compared with the traditional reflux glass powder, the glass powder of the present invention has a low reflux temperature, saves energy, is beneficial to device safety, and prolongs the service life of MEMS semiconductor devices;

[0036] 2. The present invention directly utilizes dry high-temperature steam airflow to prepare nano-glass powder, which has a narrow particle size distribution, high dispersion, and good reflow effect, thereby improving the practical application of nano-glass powder in the field of MEMS semiconductor packaging. In summary, the present invention has important application value in the field of nano-glass powder technology. DETAILED DESCRIPTION

[0037] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0038] A method for preparing MEMS semiconductor nano glass powder comprises the following steps:

[0039] Step S1, preparing a mixture: adding the raw materials except Zr2WO4(PO4)2 into a mixer of zirconium balls, mixing for 2 hours, and fully mixing to obtain a mixture;

[0040] Step S2, melting: put a crucible in a high-temperature electric furnace, add the mixture obtained in step S1, raise the temperature to 800°C at a rate of 8°C / min, then raise the temperature to 1100°C at a rate of 5°C / min, add Zr2WO4(PO4)2, stir evenly, and keep the temperature for 45 minutes to obtain a clear glass liquid;

[0041] Step S3, crushing and grinding: the clarified glass liquid obtained in step S2 is quenched in deionized water, taken out, dried and crushed, and then finely ground to nanometer particle size using a high-temperature steam jet mill, wherein the steam temperature of the high-temperature steam jet mill is 240° C. and the linear speed is 1000 m / s, to obtain MEMS semiconductor nano glass powder;

[0042] Step S4, preparing slurry: the nano glass powder obtained in step S3, a solvent (a mixed solvent of ethylene glycol and triethanolamine in a volume ratio of 1:1) and a dispersant (a mixed dispersant of sodium silicate and sodium dodecyl sulfate in a volume ratio of 1:2) are mixed and stirred evenly at a mass ratio of 100:25:0.5 to form a paste to obtain a glass powder slurry;

[0043] Step S5, glass powder reflow: the glass powder slurry obtained in step S4 is scraped and applied to the silicon microcavity, and then the nano glass powder is subjected to hot melt reflow, nitrogen is used as a protective gas, the heating rate is 20°C / min, when the temperature reaches 650°C, it is kept warm for 3 hours, after the hot melt reflow is completed, the temperature is reduced to 300°C at a cooling rate of 3°C / min, and then naturally cooled to room temperature to obtain the reflow glass for MEMS semiconductor devices;

[0044] The molar percentages of the raw materials are as follows: Bi2O3: 20-40%, TeO2: 20-40%, SiO2: 15-30%, B2O3: 1-15%, Al2O3: 1-15%, V2O5: 1-15%, Li2O: 0-10%, Na2O: 0-15%, K2O: 0-10%, MgO: 0-10%, CaO: 0-10%, SrO: 0-5%, BaO: 0-5%, MnO: 0-10%, Co2O3: 0-10%, Fe2O3: 0-10%, Zr2WO4(PO4)2: 1-10%.

[0045] According to the above experimental steps, and by controlling the dosage of the raw materials, Examples 1-6 and Comparative Examples 1-2 were obtained. The dosages of Examples 1-6 and Comparative Examples 1-2 are shown in Table 1 and Table 2, respectively:

[0046] Table 1

[0047]

[0048]

[0049] Table 2

[0050]

[0051]

[0052] The following performance tests were performed on Examples 1-6 and Comparative Examples 1-2:

[0053] The thermal expansion coefficient is determined using the national standard GB 16920-2015 "Determination of the average linear thermal expansion coefficient of glass";

[0054] The softening temperature is determined using standard ATSM 1350 "Standard Test Method for Viscosity of Glass Between Softening Point and Annealing Range";

[0055] GB / T 19077-2016 “Particle size distribution laser diffraction method” was used to determine the particle size distribution of D50 and D90;

[0056] GB / T 41742-2022 "Sealing glass for optoelectronic devices" is used to measure the bonding strength between glass and silicon wafer;

[0057] The measured results are shown in Table 3:

[0058] Table 3

[0059]

[0060]

[0061] It can be seen from Table 3 that the glass powder prepared in the embodiment of the present invention has a smaller thermal expansion coefficient than the comparative example through the selection of raw materials and the fine raw material ratio. The smaller the expansion coefficient, the better the thermal stability of the glass powder. In addition, the softening point and bonding strength of the embodiment are higher than those of the comparative example, mainly because Zr2WO4(PO4)2 is added in the embodiment. The addition of Zr2WO4(PO4)2 greatly enhances the thermal stability and mechanical properties of the glass powder. In summary, the present invention has important application value in the field of nano glass powder technology.

[0062] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0063] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A MEMS semiconductor nano glass powder, characterized in that: The invention comprises the following raw materials in molar percentage: Bi2O3: 20-40%, TeO2: 20-40%, SiO2: 15-30%, B2O3: 1-15%, Al2O3: 1-15%, V2O5: 1-15%, Li2O: 0-10%, Na2O: 0-15%, K2O: 0-10%, MgO: 0-10%, CaO: 0-10%, SrO: 0-5%, BaO: 0-5%, MnO: 0-10%, Co2O3: 0-10%, Fe2O3: 0-10%, Zr2WO4(PO4)2: 1-10%.

2. The MEMS semiconductor nano glass powder according to claim 1, characterized in that: The molar ratio of the raw materials meets the following conditions: 70%≤(Bi2O3+TeO2+SiO2)≤80%; 5%≤(MnO+Co2O3+Fe2O3)≤10%.

3. The MEMS semiconductor nano glass powder according to claim 1, characterized in that: The particle size distribution D50 of the Zr2WO4(PO4)2 is less than 50nm.

4. A method for preparing a MEMS semiconductor nano glass powder according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step S1, preparing a mixture: adding raw materials except Zr2WO4(PO4)2 into a mixer of zirconium balls, mixing, and fully mixing to obtain a mixture; Step S2, melting: put a crucible in a high-temperature electric furnace, add the mixture obtained in step S1, gradually increase the temperature to 1000-1400°C according to the step temperature, then add Zr2WO4(PO4)2 and stir evenly, and keep the temperature for 30-150 minutes to obtain a clear glass liquid; Step S3, crushing and grinding: the clarified glass liquid obtained in step S2 is quenched in deionized water, taken out, dried and crushed, and then finely ground to nanometer particle size using a high-temperature steam jet mill to obtain MEMS semiconductor nano glass powder.

5. The method for preparing a MEMS semiconductor nano glass powder according to claim 4, characterized in that: In step S3, the steam temperature of the high-temperature steam jet mill is 200-300° C., and the milling line speed is 800-1200 m / s.

6. The MEMS semiconductor nano glass powder according to claim 1, characterized in that: Application in reflow glass of MEMS semiconductor devices.

7. The use of a MEMS semiconductor nano glass powder according to claim 6, characterized in that: Specifically: Step S4, preparing slurry: mixing and stirring the MEMS semiconductor nano-glass powder, solvent and dispersant evenly to form a paste to obtain glass powder slurry; Step S5, glass powder reflux: scrape the glass powder slurry obtained in step S4 into the silicon microcavity, and then perform hot melt reflux on the nano glass powder. When the temperature reaches 600-700°C, keep it warm for 2-4 hours. After the hot melt reflux is completed, cool it down and then naturally cool it to room temperature.

8. The use of a MEMS semiconductor nano glass powder according to claim 7, characterized in that: The solvent in step S4 is one or more of ethylene glycol, triethanolamine, ethyl acetate, acetone and xylene; the dispersant is one or more of sodium silicate, Tween series, sodium dodecyl sulfate and acrylate.

9. The use of a MEMS semiconductor nano glass powder according to claim 7, characterized in that: The heating rate of the hot melt reflow in step S5 is 10-20° C. / min; the atmosphere of the hot melt reflow is one of nitrogen and helium.

10. The use of a MEMS semiconductor nano glass powder according to claim 7, characterized in that: The temperature is lowered to 300° C. at a rate of 2-4° C. / min in step S5.

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