A MEMS semiconductor nanoglass powder, a preparation method and application thereof

Abstract

The application discloses a kind of MEMS semiconductor nanometer glass powder and its preparation method and application, belong to nanometer glass powder technical field.The glass powder prepared by the selection of raw materials and fine raw material ratio, the performance of each material is fully played, and the side effect generated by each raw material is greatly weakened too much, compared with traditional reflow glass powder, the reflow temperature of the glass powder of the application is low, energy is saved, it is conducive to the safety of device, the service life of MEMS semiconductor device is improved;The application directly utilizes dry high-temperature steam flow to prepare nanometer glass powder, the particle size distribution is narrow, the dispersity is high, the reflow effect is good, the practical application of nanometer glass powder in MEMS semiconductor packaging field is improved, in conclusion, the application has important application value in nanometer glass powder technical field.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nanometer glass powder, and particularly relates to a MEMS semiconductor nanometer glass powder, a preparation method and application thereof. BACKGROUND

[0002] MEMS (Micro-Electro-Mechanical Systems) is a micro device integrating micro structures, micro sensors, micro actuators and signal processing and control circuits, and interfaces, communication and power supply on one or more chips. The specific application fields include semiconductor chips, sensors, accelerometers, resonators, gyroscopes and the like. With the rapid iteration and upgrading of electronic products, the requirements of MEMS on the air tightness and reliability of sealing products are higher and higher, and the sealing glass powder is also required to be higher.

[0003] Wafer level packaging is the leading trend and research focus of MEMS packaging technology. First, the MEMS sensitive unit is manufactured on the silicon wafer, 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 packaged by vacuum 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, which ensures that the movable parts have enough movement space, and at the same time the cap and the substrate are tightly combined to meet the vacuum degree requirement in the cavity. The electrical signal is usually introduced through vertical interconnection, that is, the electrical signal is vertically introduced, which supports three-dimensional chip stacking, shortens the transmission distance of the electrical signal, and reduces signal interference. Vertical interconnection technology includes glass vertical interconnection (Through Glass Via-TGV) and silicon vertical interconnection (Through Silicon Via-TSV), among which TGV is more widely used due to its small parasitic capacitance, good heat insulation, and simple bonding process (mainly anodic bonding). Glass not only has good insulation, but also has good thermal matching coefficient with silicon, effectively avoiding the device failure problem caused by excessive thermal stress after bonding. The biggest challenge of TGV technology lies in the design of the via, and the glass reflow process solves the problem of etching the via on the glass. The traditional TGV process includes etching a microcavity on a silicon wafer, then anodically bonding the silicon wafer with glass, filling the microcavity with glass by heating, and finally mechanical chemical polishing to form a TGV cap. However, the main shortcomings of the existing glass reflow process include: first, during anodic bonding, the surface roughness of glass and silicon is high, and the bonding environment requires high vacuum; the chemical properties of the glass surface change after bonding; second, during glass heating and reflow, there are problems such as high temperature, long time, easy to form crystals, insufficient filling of microcavity edges, easy to form cavities inside, filling speed slows down as the cavity shrinks, filling width is usually not less than 100 microns and the cavity with a sidewall angle less than 90 degrees is difficult to fill; third, there are problems such as long polishing time and high polishing cost in the polishing process. SUMMARY

[0004] The purpose of the present application is to overcome the defects of the prior art and provide a MEMS semiconductor nanometer glass powder, a preparation method and application thereof.

[0005] The purpose of the present application can be achieved by the following technical solutions:

[0006] A kind of MEMS semiconductor nanometer glass powder includes the following molar percentage of raw materials: 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%.

[0007] Further, the molar ratio between the raw materials satisfies the following conditions: 70%≤(Bi2O3+TeO2+SiO2)≤80%; 5%≤(MnO+Co2O3+Fe2O3)≤10%.

[0008] Further, the particle size distribution D50 of Zr2WO4 (PO4) 2 is less than 50 nm.

[0009] Further, as a preferred technical solution of the present application, a kind of MEMS semiconductor nanometer glass powder includes the following molar percentage of raw materials: 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%.

[0010] A preparation method of a kind of MEMS semiconductor nanometer glass powder, comprising the following steps:

[0011] Step S1, preparation of mixed material: the raw materials except Zr2WO4 (PO4) 2 are added into the mixing machine of zirconium ball, and the mixing time is 1-3h, after being mixed uniformly, the mixed material is obtained;

[0012] Step S2, melting: the mixed material obtained in step S1 is added into the crucible in high-temperature electric furnace, and the temperature is gradually increased to 1000-1400 DEG C according to ladder temperature, then Zr2WO4 (PO4) 2 is added and stirred uniformly, and after being kept for 30-150 min, the clear glass liquid is obtained;

[0013] Step S3, crushing and grinding: the clarified glass liquid obtained in step S2 is taken out after water quenching in deionized water, dried, crushed, and then finely ground to nanoscale particle size by high-temperature steam jet milling to obtain MEMS semiconductor nanoglass powder;

[0014] Step S4, preparing slurry: the nanoglass powder obtained in step S3, a solvent, and a dispersant are mixed and stirred uniformly to form a paste, thereby obtaining glass powder slurry;

[0015] Step S5, glass powder reflow: the glass powder slurry obtained in step S4 is coated into a silicon microcavity, and the nanoglass powder is then heat-treated and reflowed. When the temperature reaches 600-700°C, the heat treatment is maintained for 2-4 hours. After the heat reflow is completed, the temperature is lowered and then naturally cooled to room temperature to obtain reflow glass for MEMS semiconductor devices.

[0016] Further, the steam temperature of the high-temperature steam jet mill in step S3 is 200-300°C, and the crushing linear speed is 800-1200 m / s.

[0017] Further, the solvent in step S4 is one or more of ethylene glycol, triethanolamine, ethyl acetate, acetone, and dimethylbenzene.

[0018] Further, the dispersant in step S4 is one or more of sodium silicate, Tween series, sodium dodecyl sulfonate, and acrylic ester.

[0019] Further, the mass ratio of the nanoglass powder, the solvent, and the dispersant in step S4 is 100:25:0.5.

[0020] Further, the heating rate of the heat reflow in step S5 is 10-20°C / min, and the atmosphere of the heat reflow is one of nitrogen and helium.

[0021] Further, the cooling condition in step S5 is a cooling rate of 2-4°C / min to 300°C.

[0022] The addition of Bi2O3, a glass network former oxide, to the raw material imparts excellent chemical stability to the glass powder and reduces the melting temperature of the glass powder.

[0023] The addition of TeO2, also a glass network former oxide, to the raw material improves the mechanical strength of the glass powder, because the structural units in the glass powder mainly include four-coordinated [TeO4] and three-coordinated [TeO3], and exist in the form of Te-O-Te chain structure or more complex fabric network structure.

[0024] The addition of SiO2, an important glass network former oxide, to the raw material constitutes the skeleton structure of the glass, reduces the thermal expansion coefficient of the glass powder, and improves the mechanical strength of the glass powder.

[0025] The B2O3 added in the raw material is a glass network forming body oxide, which is beneficial to improve the melting property of the glass powder and reduce the viscosity of the glass powder;

[0026] The Al2O3 added in the raw material is a glass network intermediate oxide, and aluminum forms aluminum oxygen tetrahedron in the glass, which plays a role in improving and strengthening the structure of the low-melting-point glass, and also reduces the crystallization tendency of the glass powder and improves a series of performances of the glass powder;

[0027] The Li2O, Na2O and K2O added in the raw material are alkali metal oxides, which are glass network external oxides, and the addition of the three alkali metal oxides forms a mixed alkali effect, thereby improving the thermal and mechanical properties of the glass powder;

[0028] The MgO, CaO, SrO and BaO added in the raw material are alkaline earth metal oxides, which do not participate in the network structure and belong to the network external body, wherein the MgO and CaO are beneficial to improve the stability of the glass powder, the SrO and BaO are beneficial to reduce the softening point of the glass powder, improve the flowability of the glass powder in the low-temperature region, and improve the production conditions and crystallization properties of the glass powder, thereby enhancing the hardness and corrosion resistance of the glass powder;

[0029] The V2O5, MnO, Co2O3 and Fe2O3 added in the raw material can jointly act, and through appropriate proportioning, the thermal expansion coefficient of the glass powder can be greatly reduced;

[0030] The Zr2WO4(PO4)2 added in the raw material is introduced in the form of nanoscale raw material, which has nanoscale properties in terms of small size effect, surface effect and interface effect, has a short melting time and is randomly distributed in the glass powder, and is beneficial to improve the mechanical strength and thermal stability of the glass powder.

[0031] Advantages of the present application:

[0032] 1. The glass powder prepared by the present application fully utilizes the performance of each material through the selection and fine proportioning of the raw materials, and greatly reduces the side effects caused by excessive use of each raw material. Compared with the traditional reflow glass powder, the reflow temperature of the glass powder of the present application is low, energy is saved, the device safety is improved, and the service life of the MEMS semiconductor device is improved.

[0033] 2. The present application directly uses dry high-temperature steam gas flow to prepare nanoscale glass powder, which has narrow particle size distribution, high dispersity and good reflow effect, thereby improving the practical application of the nanoscale glass powder in the field of MEMS semiconductor packaging. In summary, the present application has important application value in the technical field of nanoscale glass powder. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of the present application.

[0035] A preparation method of a MEMS semiconductor nanoglass powder, comprising the following steps:

[0036] Step S1, preparing a mixture: adding raw materials except Zr2WO4(PO4)2 into a mixer of zirconium balls, mixing for 2 hours, and obtaining a mixture after fully mixing and uniformly mixing;

[0037] Step S2, melting: loading a crucible into a high-temperature electric furnace, adding the mixture obtained in step S1, increasing the temperature to 800 DEG C at a rate of 8 DEG C / min, then increasing the temperature to 1100 DEG C at a rate of 5 DEG C / min, adding Zr2WO4(PO4)2, stirring uniformly, and performing heat preservation for 45 min, and obtaining a clear glass liquid;

[0038] Step S3, crushing and grinding: taking out the clear glass liquid obtained in step S2 after water quenching in deionized water, drying, crushing, and then performing fine grinding to a nanoscale particle size by using a high-temperature steam jet mill, wherein the steam temperature of the high-temperature steam jet mill is 240 DEG C, and the linear velocity is 1000 m / s, and obtaining a MEMS semiconductor nanoglass powder;

[0039] Step S4, preparing a slurry: mixing and stirring uniformly the nanoglass powder obtained in step S3, a solvent (a mixed solvent of ethylene glycol and triethanolamine with a volume ratio of 1:1) and a dispersing agent (a mixed dispersing agent of sodium silicate and sodium dodecyl sulfate with a volume ratio of 1:2) at a mass ratio of 100:25:0.5 to form a paste, and obtaining a glass powder slurry;

[0040] Step S5, glass powder reflowing: coating the glass powder slurry obtained in step S4 into a silicon microcavity by scraping, and then performing thermal reflow of the nanoglass powder, using nitrogen as a protective gas, increasing the temperature at a rate of 20 DEG C / min, and when the temperature reaches 650 DEG C, performing heat preservation for 3 h, and then decreasing the temperature to 300 DEG C at a rate of 3 DEG C / min, and then naturally cooling to room temperature, and obtaining a reflow glass for a MEMS semiconductor device;

[0041] The molar percentage of the raw materials is 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%.

[0042] According to the above experimental steps, and controlling the amount of raw materials, examples 1-6 and comparative examples 1-2 are obtained, and the amount of examples 1-6 and comparative examples 1-2 is shown in table 1 and table 2 respectively:

[0043] Table 1

[0044]

[0045]

[0046] Table 2

[0047]

[0048]

[0049] Examples 1-6 and comparative examples 1-2 are subjected to the following performance tests:

[0050] The coefficient of thermal expansion is determined by using the national standard GB 16920-2015 "Determination of average linear coefficient of thermal expansion of glass";

[0051] The softening temperature is determined by using the standard ATSM 1350 "Standard test method for measuring glass viscosity between softening point and annealing range";

[0052] The particle size distribution of D50 and D90 is determined by using GB / T 19077-2016 "Particle size distribution laser diffraction method";

[0053] The glass and silicon wafer bonding strength is determined by using GB / T 41742-2022 "Sealing glass for optoelectronic devices";

[0054] The measured results are shown in table 3:

[0055] Table 3

[0056]

[0057]

[0058] As shown in Table 3, the glass powder prepared by the selection of raw materials and fine raw material ratio has a smaller thermal expansion coefficient than the comparative example, and the smaller the expansion coefficient, the better the thermal stability of the glass powder; in addition, the softening point and the bonding strength of the embodiment are higher than those of the comparative example, mainly because Zr2WO4(PO4)2 is added in the embodiment, and the addition of Zr2WO4(PO4)2 greatly enhances the thermal stability and mechanical properties of the glass powder; in summary, the application has important application value in the technical field of nano glass powder.

[0059] In the description of the specification, the description of the terms "one embodiment", "an example", "a specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the application. In the specification, the illustrative description 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.

[0060] The above is only an example and description of the application, and those skilled in the art can make various modifications or supplements or use similar ways to replace the described specific embodiments, as long as they do not deviate from the application or exceed the scope defined by the claims, which shall belong to the protection scope of the application.

Claims

1. A MEMS semiconductor nanoglass powder, characterized by, The raw materials include the following in terms of mole 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 nanoglass powder of claim 1, wherein, The mole ratio between the raw materials satisfies the following conditions: 70%≤(Bi2O3+TeO2+SiO2)≤80%; 5%≤(MnO+Co2O3+Fe2O3)≤10%.

3. The MEMS semiconductor nanoglass powder of claim 1, wherein, The particle size distribution D50 of the Zr2WO4(PO4)2 is less than 50 nm.

4. The method of any one of claims 1-3, wherein the MEMS semiconductor nanoglass powder is prepared by the method comprising: The method includes the following steps: ​ Step S1, preparing a mixture: adding the raw materials except for Zr2WO4(PO4)2 into a mixer of a zirconium ball, mixing, and obtaining a mixture after fully mixing; Step S2, melting: loading a crucible into a high-temperature electric furnace, adding the mixture obtained in step S1, gradually increasing the temperature according to a step temperature until 1000-1400℃, then adding Zr2WO4(PO4)2, stirring uniformly, and obtaining a clear glass liquid after heat preservation for 30-150 min; Step S3, crushing and grinding: taking out the clear glass liquid obtained in step S2 after water quenching in deionized water, drying, crushing, and then performing fine grinding to a nano-level particle size by using a high-temperature steam jet mill to obtain a MEMS semiconductor nano glass powder.

5. The method of claim 4, wherein the MEMS semiconductor nanoglass powder is prepared by the steps of: The steam temperature of the high-temperature steam jet mill in step S3 is 200-300℃, and the crushing linear velocity is 800-1200 m / s.

6. Application of the MEMS semiconductor nano glass powder of claim 1 in reflow glass of a MEMS semiconductor device.

7. Use according to claim 6, characterized in that, Specifically: Step S4, preparing a slurry: mixing and stirring the MEMS semiconductor nano glass powder, a solvent, and a dispersant uniformly to form a paste, and obtaining a glass powder slurry; Step S5, glass powder reflow: coating the glass powder slurry obtained in step S4 into a silicon microcavity, and then performing heat reflow on the nano glass powder, and when the temperature reaches 600-700℃, heat preservation is performed for 2-4 h, and after the heat reflow is completed, cooling is performed, and then natural cooling is performed to room temperature.

8. Use according to claim 7, characterized in that, The solvent in step S4 is one or more of ethylene glycol, triethanolamine, ethyl acetate, acetone, and dimethylbenzene; and the dispersant is one or more of sodium silicate, a Tween series, sodium dodecyl sulfonate, and acrylate.

9. Use according to claim 7, characterized in that, The heating rate of the heat reflow in step S5 is 10-20℃ / min; and the atmosphere of the heat reflow is one of nitrogen and helium.

10. Use according to claim 7, characterized in that, The cooling condition in step S5 is to reduce the temperature to 300℃ at a cooling rate of 2-4℃ / min.

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