阅读说明：本技术 一种陶瓷电容压力传感器芯片的封接方法 (Sealing method of ceramic capacitor pressure sensor chip ) 是由 邵海成 乔冠军 刘炘城 黄清伟 刘桂武 张相召 陆浩杰 于 2020-05-13 设计创作，主要内容包括：本发明公开了一种陶瓷电容式压力传感器芯片的封接方法。该方法为：一、陶瓷基底表面打磨、清洗、烘干；二、在基底上丝网印刷玻璃浆料；三、烘干处理；四、加压烧结；五、侧面玻璃浆料涂刷；六、二次烧结成型。本发明制备的陶瓷电容式压力传感器芯片经过氟油和氦气密封性检测,密封性能好,压力弹片与陶瓷基底结合强度大于40MPa,陶瓷弹片与陶瓷基底间距可以控制在10μm～50μm。本发明具有工艺简单、密封效果好、粘接强度高、电容间距可控性好等优点。(The invention discloses a sealing method of a ceramic capacitive pressure sensor chip. The method comprises the following steps: firstly, polishing, cleaning and drying the surface of a ceramic substrate; secondly, screen printing glass slurry on the substrate; thirdly, drying; fourthly, pressure sintering; fifthly, brushing the glass slurry on the side surface; sixthly, secondary sintering and forming. The ceramic capacitive pressure sensor chip prepared by the invention is good in sealing performance after being subjected to the tightness detection of fluorine oil and helium, the bonding strength of the pressure elastic sheet and the ceramic substrate is more than 40MPa, and the distance between the ceramic elastic sheet and the ceramic substrate can be controlled to be 10-50 mu m. The invention has the advantages of simple process, good sealing effect, high bonding strength, good controllability of capacitor spacing and the like.)

1. A sealing method of a ceramic capacitive pressure sensor chip is characterized by comprising the following steps:

the method comprises the following steps: the ceramic capacitive pressure sensor chip is prepared by taking a ceramic material as a substrate of the ceramic capacitive pressure sensor chip, and grinding, cleaning and drying the surface of the ceramic material for later use;

step two: adopting glass slurry as a sealing material, and printing the glass slurry on the ceramic surface which is processed in the first step and is plated with an electrode by adopting a screen printing method;

step three: placing the ceramic substrate printed with the glass slurry in the step two in an oven for drying;

step four: pressing the ceramic sheet dried in the third step as a substrate, pressing the ceramic elastic sheet with the electrode plated on the surface on the ceramic substrate printed with the glass slurry, and placing the ceramic elastic sheet in a high-temperature furnace for pressure sintering molding;

step five: and (4) coating the side surface of the sensor chip discharged from the furnace in the fourth step with glass slurry as used in the second step, drying the sensor chip in the third step again, and then placing the sensor chip in a high-temperature furnace for secondary sintering molding to obtain the ceramic capacitive pressure sensor chip.

2. A method for sealing a ceramic capacitive pressure sensor chip as claimed in claim 1, wherein in the first step, the surface polishing is performed by polishing the surface of the ceramic with a polishing machine, and the roughness of the polished surface of the ceramic is controlled to be 0.05 μm to 2.0 μm; the cleaning is ultrasonic cleaning with alcohol or acetone for 20-120 min; the drying is carried out in an oven, the drying temperature is controlled to be 75-120 ℃, and the drying time is 0.5-2.0 h.

3. A method for sealing a ceramic capacitive pressure sensor die as claimed in claim 1, wherein in step one, the ceramic material is a pure oxide ceramic orA non-oxide ceramic, the pure oxide ceramic being Al₂O₃、ZrO₂MgO, CaO, BeO or ThO₂(ii) a The non-oxide ceramic is one of carbide, boride, nitride and silicide ceramic.

4. A method of sealing a ceramic capacitive pressure sensor die as claimed in claim 1, wherein in step two, the glass paste is one of silicate glass, phosphate glass, borate glass and aluminate glass; the viscosity of the glass slurry is controlled to be 80pa s-400 pa s, the screen printing frequency is 1-10 times, the mesh number is 100-500 meshes, and the distance between the mesh and the ceramic substrate is 1.0-30 mm.

5. A method for sealing a ceramic capacitive pressure sensor chip according to claim 1, wherein in the third step, the drying temperature is controlled to 75-120 ℃ for 0.5-2.0 h.

6. The method for sealing a ceramic capacitive pressure sensor chip according to claim 1, wherein in the fourth step, the ceramic dome is a pure oxide ceramic or a non-oxide ceramic, and the pure oxide ceramic is Al₂O₃、ZrO₂MgO, CaO, BeO or ThO₂(ii) a The non-oxide ceramic is one of carbide, boride, nitride and silicide ceramic; the pressure sintering forming process in the high-temperature furnace comprises the following steps: the sintering temperature is 350-1000 ℃, the heating rate is 5-30 ℃/min, the heat preservation time is 0.5-2.0 h, the temperature is naturally reduced, and the applied pressure is 5-50 kPa.

7. The method for sealing a ceramic capacitive pressure sensor chip according to claim 1, wherein in the fifth step, the secondary sintering process comprises the steps of sintering at a temperature of 350 ℃ to 1000 ℃, raising the temperature at a speed of 5 ℃/min to 30 ℃/min, keeping the temperature for 0.5h to 2.0h, and naturally cooling.

8. A sealing method of a ceramic capacitive pressure sensor chip according to claim 1, wherein the ceramic capacitive pressure sensor chip has good sealing performance through the detection of the sealing performance of fluorine oil and helium gas, the bonding strength of the ceramic elastic sheet and the ceramic substrate is more than 40MPa, and the distance between the ceramic elastic sheet and the ceramic substrate can be controlled to be 10-50 μm.

Technical Field

The invention relates to the field of sensors, in particular to a sealing method of a ceramic capacitive pressure sensor chip.

Background

Ceramic capacitive pressure sensors were first studied from the eighties of the twentieth century. Through the continuous development of more than ten years, the novel pressure sensor tends to mature in the late stage of the nineties, and a plurality of product series are released by a plurality of foreign companies, so that the novel pressure sensor rapidly occupies the market. Due to the advantages of low cost, long service life, strong measurement repeatability and the like, the ceramic capacitive pressure sensor still firmly occupies a large share of the market today when the MEMS pressure sensor is rapidly developed, and the market position is difficult to swing. In China, research and development work of ceramic capacitive pressure sensors starts to be carried out in the middle of ninety years under the subsidization of national and provincial projects, certain progress is made in the field of pressure sensors with medium and high pressure measuring ranges, and a considerable distance exists in the aspect of large-scale industrial production. Both the manufacturing technology and the material process in China are relatively lagged behind, and the technical requirements of the automobile industry cannot be met. Hundreds of millions of vehicular pressure sensors are currently monopolized by foreign products every year on the market. The ceramic capacitive pressure sensor integrates advanced ceramic sheet manufacturing, precise size control, electrode and vacuum packaging, electronic circuits and the like, has complex technical requirements, has high requirements on performance indexes, particularly repeatability, stability and reliability, and can not meet the requirements at home at present. At present, the ceramic capacitive pressure sensor process has some defects: (1) the packaging between the electrodes is difficult, the distance is difficult to control, and the reliability is poor; (2) the sealing performance of the capacitor cavity is poor, the bonding performance of the ceramic elastic sheet and the ceramic substrate is poor, and the fatigue resistance performance of the sensor under the action of cyclic stress is poor.

Disclosure of Invention

The invention aims to provide a sealing method of a ceramic capacitive pressure sensor chip, which has the advantages of simple process, good sealing effect, high bonding strength and good controllability of capacitor spacing, aiming at the defects of the prior art.

In order to achieve the purpose, the invention adopts the technical scheme that: a sealing method of a ceramic capacitance type pressure sensor chip is characterized by comprising the following steps:

the method comprises the following steps: the ceramic capacitive pressure sensor chip is prepared by taking a ceramic material as a substrate of the ceramic capacitive pressure sensor chip, and grinding, cleaning and drying the surface of the ceramic material for later use;

step two: adopting glass slurry as a sealing material, and printing the glass slurry on the ceramic surface which is processed in the first step and is plated with an electrode by adopting a screen printing method;

step three: placing the ceramic substrate printed with the glass slurry in the step two in an oven for drying;

step four: pressing the ceramic sheet dried in the third step as a substrate, pressing the ceramic elastic sheet with the electrode plated on the surface on the ceramic substrate printed with the glass slurry, and placing the ceramic elastic sheet in a high-temperature furnace for pressure sintering molding;

step five: and (4) coating the side surface of the sensor chip discharged from the furnace in the fourth step with the glass slurry used in the second step, drying the sensor chip in the third step, and then placing the sensor chip in a high-temperature furnace for secondary sintering molding to obtain the ceramic capacitive pressure sensor chip.

The sealing method of the ceramic capacitive pressure sensor chip is characterized in that in the first step, the surface polishing refers to polishing the ceramic surface by a polishing machine, and the roughness of the polished ceramic surface is controlled to be 0.05-2.0 mu m; the cleaning is ultrasonic cleaning with alcohol or acetone for 20-120 min; the drying is carried out in an oven, the drying temperature is controlled to be 75-120 ℃, and the drying time is 0.5-2.0 h.

The method for sealing the ceramic capacitive pressure sensor chip is characterized in that in the step one, the ceramic material is pure oxide ceramic or non-oxide ceramic, and the pure oxide ceramic is Al₂O₃、ZrO₂MgO, CaO, BeO or ThO₂(ii) a The non-oxide ceramic is one of carbide, boride, nitride and silicide ceramic.

The method for sealing the ceramic capacitive pressure sensor chip is characterized in that in the second step, the glass slurry is one of silicate glass, phosphate glass, borate glass and aluminate glass. The viscosity of the glass slurry is controlled to be 80pa s-400 pa s, the screen printing frequency is 1-10 times, the mesh number is 100-500 meshes, and the distance between the mesh and the ceramic substrate is 1.0-30 mm.

The sealing method of the ceramic capacitive pressure sensor chip is characterized in that in the third step, the drying temperature is controlled to be 75-120 ℃ and the time is 0.5-2.0 h.

The method for sealing the ceramic capacitive pressure sensor chip is characterized in that in the fourth step, the ceramic elastic sheet is pure oxide ceramic or non-oxide ceramic, and the pure oxide ceramic is Al₂O₃、ZrO₂MgO, CaO, BeO or ThO₂(ii) a The non-oxide ceramic is one of carbide, boride, nitride and silicide ceramic. The pressure sintering forming process in the high-temperature furnace comprises the following steps: the sintering temperature is 350-1000 ℃, the heating rate is 5-30 ℃/min, the heat preservation time is 0.5-2.0 h, the temperature is naturally reduced, and the applied pressure is 5-50 kPa.

The sealing method of the ceramic capacitive pressure sensor chip is characterized in that in the fifth step, the secondary sintering process comprises the steps of sintering at the temperature of 350-1000 ℃, heating at the speed of 5-30 ℃/min, keeping the temperature for 0.5-2.0 h, and naturally cooling.

The ceramic capacitive pressure sensor chip prepared by the technical scheme has good sealing performance through the tightness detection of fluorine oil and helium, the bonding strength of the ceramic elastic sheet and the ceramic substrate is more than 40MPa, and the distance between the ceramic elastic sheet and the ceramic substrate can be controlled to be 10-50 mu m. Compared with the prior art, the invention has the following advantages:

1. according to the invention, through the secondary sealing and pressure sintering molding technology, the sealing performance of the sensor chip and the bonding performance between the ceramic elastic sheet and the ceramic substrate are improved by the sealing technology.

2. The ceramic substrate and the ceramic elastic sheet material selected by the invention have excellent performances of strong thermal stability, acid and alkali corrosion resistance, strong anti-interference capability and the like.

Drawings

FIG. 1 is a block diagram of a process flow for a method of sealing a ceramic capacitive pressure sensor die according to the present invention.

Detailed Description