Batch packaging method and packaging equipment for MEMS electric field sensors

Abstract

The invention provides a batch packaging method and packaging equipment for MEMS electric field sensors, and the method comprises the steps: fixing an electric field sensitive chip which meets the requirements on the end surface of the inner side of a packaging tube shell; connecting the electric field sensitive chip with a specified welding spot through a lead, and detecting whether the tension of the lead and the thrust of the gold ball meet requirements or not; the packaging cavity, the packaging cover plate, the packaging tube shell meeting the requirement and the material box are pretreated so as to meet the requirement before welding; and in the packaging cavity, performing seam welding on the packaging cover plate and the packaging tube shell so as to fix the packaging cover plate on the packaging tube shell, and warehousing the MEMS electric field sensor meeting the requirements. The packaging equipment for implementing the batch packaging method comprises an electric field sensitive chip fixing part, a bonding wire testing part, a preprocessing part and a welding testing part. According to the invention, the MEMS electric field sensors can be packaged in batches, and the defects of low efficiency, poor product consistency, low air tightness and low yield in the existing packaging process are overcome.

Description

TECHNICAL FIELD

[0001] The present application relates to a packaging method, in particular to a batch packaging method and packaging equipment for MEMS electric field sensors. BACKGROUND

[0002] MEMS electric field sensors are mainly applied in the fields of national defense, aviation, aerospace, meteorology, petrochemical industry, electrostatics, etc., and play a very important role in the above-mentioned fields.

[0003] The packaging process of MEMS electric field sensors is a key technology affecting the practicality of MEMS electric field sensors, and has been concerned in recent years. In the existing packaging process, the packaging of a single MEMS electric field sensor is mainly completed one by one. For example, when using SSEC2400E or AMADA8500 equipment of the United States for welding process, the packaging shell needs to be placed in a glove box, and the packaging cover plate is manually taken out for process debugging and operation. This method has the characteristics of low efficiency, poor product consistency, poor air tightness, and low yield.

[0004] Therefore, how to solve the problems of low efficiency, poor product consistency, low air tightness, and low yield in the existing packaging process is a technical problem to be solved at present. SUMMARY

[0005] In view of the above problems, the present application provides a batch packaging method and packaging equipment for MEMS electric field sensors, which can batch package MEMS electric field sensors and solve the problems of low efficiency, poor product consistency, low air tightness, and low yield in the existing packaging process.

[0006] To achieve the above-mentioned purpose, in a first aspect, the present application provides a batch packaging method for MEMS electric field sensors, comprising the following steps:

[0007] S1, fixing the required electric field sensitive chip on the inner side end face of the packaging shell, wherein, comprising:

[0008] Checking the electric field sensitive chip and screening out the electric field sensitive chip not meeting the preset condition;

[0009] Plasma cleaning the packaging cover plate and the packaging shell;

[0010] Stacking the electric field sensitive chip meeting the preset condition on the bonding area formed on the inner side end face of the packaging shell, and after the glue is baked and cured, the electric field sensitive chip is fixed on the central area of the inner side end face of the packaging shell;

[0011] S2, connecting the electric field sensitive chip with the designated welding spot through lead wire and detecting whether the pulling force of the lead wire and the pushing force of the gold ball meet the requirements;

[0012] S3, pre-treating the packaging cavity, the packaging cover plate, the packaging tube shell and the material box to meet the requirements before welding, including:

[0013] After placing the packaging cover plate and the packaging tube shell in the material box, put them into the packaging cavity;

[0014] Adjust the water and oxygen content in the packaging cavity to a preset value and the vacuum degree to a specified micro-negative pressure state;

[0015] Remove the water vapor and impurities on the packaging cover plate, the packaging tube shell and the material box;

[0016] S4, in the packaging cavity, seam welding the packaging cover plate and the packaging tube shell to fix the packaging cover plate on the packaging tube shell, and storing the MEMS electric field sensor that meets the requirements, including:

[0017] Position and compress the packaging cover plate on the top end face of the packaging cover plate, seam weld between the packaging cover plate and the packaging tube shell in parallel, and after the valve weld ring is melted, the packaging cover plate is fixed on the packaging tube shell;

[0018] Check whether the MEMS electric field sensor after welding meets the requirements, and store the MEMS electric field sensor that meets the requirements.

[0019] In one embodiment, after the electric field sensitive chip that meets the preset conditions is superimposed on the bonding area formed on the inner side end face of the packaging tube shell, the electric field sensitive chip is fixed in the central area of the inner side end face of the packaging tube shell after the glue is baked and cured, including:

[0020] Form the bonding area of the electric field sensitive chip on the specified position of the inner end face of the packaging tube shell;

[0021] Superimpose the electric field sensitive chip that meets the preset conditions on the bonding area;

[0022] Check the offset and inclination angle of the electric field sensitive chip on the bonding area to ensure that the electric field sensitive chip meets the requirements of patching;

[0023] Bake the packaging tube shell with the electric field sensitive chip, and after the glue is baked and cured, fix the electric field sensitive chip in the packaging tube shell;

[0024] Check whether the fixing performance of the electric field sensitive chip meets the requirements.

[0025] In one embodiment, after the electric field sensitive chip is connected to the designated soldering point through the lead, the performance of the pulling force of the lead and the pushing force of the gold ball are tested, including:

[0026] Placing the package shell into a soldering machine, so that the first end of the lead is connected to the designated soldering point of the package shell, and the second end of the lead is connected to the electric field sensitive chip;

[0027] Detecting whether the pulling force of the lead and the pushing force of the gold ball meet the requirements.

[0028] In one embodiment, after the water and oxygen content inside the package cavity is adjusted to a preset value, and the vacuum degree is adjusted to a specified micro-negative pressure state, including:

[0029] Injecting nitrogen into the package cavity, and vacuumizing the inside of the package cavity;

[0030] After repeating multiple times, the water and oxygen content inside the package cavity reaches a preset value, and the vacuum degree is in a specified micro-negative pressure state, wherein:

[0031] The preset value of the water and oxygen content is a water vapor dew point value of -60°C, and the oxygen content is less than 5ppm, and the specified micro-negative pressure state is less than 1 standard atmosphere.

[0032] In one embodiment, after removing the water vapor and impurities on the package cover plate, the package shell and the cartridge, including:

[0033] The inside of the package cavity is heated to a set temperature value according to a preset heating time threshold value under a specified micro-negative pressure state, and the set temperature value is maintained for a preset time value, wherein:

[0034] The preset heating time threshold value is 30 to 45 minutes, the set constant temperature value is at least 200°C, and the preset time value is at least 120 minutes.

[0035] In one embodiment, after the package cavity, the package cover plate and the package shell are seam welded to fix the package cover plate on the package shell, and the MEMS electric field sensor meeting the requirements is put into the cartridge, including:

[0036] Judging whether the fixed position of the package cover plate on the package shell after welding meets the requirements;

[0037] Judging whether there are leaks between the package cover plate and the package shell;

[0038] Testing whether the performance of the MEMS electric field sensor meets the packaging requirements.

[0039] In a second aspect, the present application further provides a packaging device for implementing the batch packaging method of the MEMS electric field sensor, comprising an electric field sensitive chip fixing part, a wire bonding testing part, a pretreatment part and a welding testing part, wherein:

[0040] The electric field sensitive chip fixing part is used for fixing the qualified electric field sensitive chip on the inner end face of the packaging tube shell, and comprises a wafer detection device, an ultrasonic cleaning device, a fixing device and a wire bonding testing device.

[0041] The wafer detection device is used for judging whether the electric field sensitive chip meets the preset condition according to the preset condition, and forming a Mapping diagram according to the electric field sensitive chip not meeting the preset condition.

[0042] The ultrasonic cleaning device is used for performing plasma cleaning on the packaging cover plate and the packaging tube shell.

[0043] The fixing device is used for superimposing the electric field sensitive chip meeting the preset condition on the bonding area formed on the inner end face of the packaging tube shell, and fixing the electric field sensitive chip in the central area of the inner end face of the packaging tube shell after the glue is cured by baking.

[0044] The wire bonding testing part is used for connecting the electric field sensitive chip and the specified welding point through a lead wire, and detecting whether the pulling force of the lead wire and the pushing force of the gold ball meet the requirements, and comprises a wire bonding machine and a first testing device, wherein:

[0045] The wire bonding machine is used for connecting the first end of the lead wire and the specified welding point in the packaging tube shell, and connecting the second end of the lead wire and the electric field sensitive chip.

[0046] The first testing device is used for testing whether the electrical performance between the electric field sensitive chip, the lead wire and the specified welding point meets the requirements.

[0047] The pretreatment part is used for pretreating the packaging cavity, the packaging cover plate, the qualified packaging tube shell and the magazine to meet the requirements before welding.

[0048] The welding testing part is used for seam welding the packaging cover plate and the packaging tube shell in the packaging cavity to fix the packaging cover plate on the packaging tube shell, and storing the qualified MEMS electric field sensor in the magazine, and comprises a parallel seam welding machine and a testing device, wherein:

[0049] The parallel seam welding machine is used for parallel seam welding between the packaging cover plate and the packaging tube shell, and the packaging cover plate is fixed on the packaging tube shell after the valve welding ring is melted.

[0050] The test device is used to check whether the MEMS electric field sensor after welding meets the requirements.

[0051] In one embodiment, the fixing device includes a dispensing mechanism, a patching mechanism, a three-axis industrial microscope, a baking device, and a push-pull force testing machine, wherein:

[0052] The dispensing mechanism is used to dispense glue on a specified position of the inner end face of the package tube to form an adhesive area;

[0053] The patching mechanism is used to superimpose the electric field sensitive chip meeting the requirements on the adhesive area;

[0054] The three-axis industrial microscope is used to check the offset and tilt angle of the electric field sensitive chip on the adhesive area to ensure that the electric field sensitive chip meets the patching requirements;

[0055] The baking device is used to bake the package tube with the electric field sensitive chip placed therein, and after the glue is cured by baking, the electric field sensitive chip is fixed in the central area inside the package tube;

[0056] The push-pull force testing machine is used to check whether the fixing performance of the electric field sensitive chip meets the requirements.

[0057] In one embodiment, the pre-processing part includes a nitrogen machine, a vacuum pumping device, and a heating device, wherein:

[0058] The nitrogen machine is used to inject nitrogen into the packaging cavity;

[0059] The vacuum pumping device is used to pump out the mixed gas in the packaging cavity, so that the water and oxygen content inside the packaging cavity reaches a preset value, and the vacuum degree is in a specified micro-negative pressure state;

[0060] The heating device is used to heat the internal temperature of the packaging cavity to a set temperature value according to a preset temperature rise time threshold, and maintain the set temperature value for a preset time value, so as to remove water vapor and impurities on the packaging cover plate, the packaging tube, and the cartridge.

[0061] In one embodiment, the test device includes a visual recognition device, a fluorine oil helium mass spectrometric leak detector, and a second test device, wherein:

[0062] The visual recognition device is used to determine whether the fixed position of the packaging cover plate on the packaging tube after welding meets the requirements;

[0063] The fluorine oil helium mass spectrometric leak detector is used to determine whether there is a leak point at the welding position between the packaging cover plate and the packaging tube;

[0064] The second testing device is used to determine whether the performance of the MEMS electric field sensor meets packaging requirements.

[0065] Compared with the prior art, the present invention has one of the following advantages:

[0066] By using the above-mentioned packaging method and packaging equipment, MEMS electric field sensors can be packaged in batches, thereby solving the shortcomings of low efficiency, poor product consistency, low airtightness, and low yield in the existing packaging process.

[0067] By adding a pretreatment step for the package cover, package shell, electric field sensitive chip and package cavity, moisture and impurities on the package cover, package shell and electric field sensitive chip can be removed, and the water and oxygen content inside the package cavity can be ensured to reach a preset value and the vacuum degree to be in a specified micro-negative pressure state. After the valve welding ring is melted, the package cover is fixed to the open end surface of the package shell, which can ensure the airtightness of the MEMS electric field sensor after packaging.

[0068] The packaging method includes multiple inspection and testing steps, which can promptly determine whether the device meets the preset conditions, thereby improving the yield rate;

[0069] By adding a three-axis industrial microscope, a push-pull force testing machine, a first testing device, a visual recognition device, a fluorine oil helium mass spectrometer leak detector and a second testing device, it is possible to determine whether the devices in the corresponding steps meet the corresponding requirements, thereby improving the yield rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 Flowchart of the batch packaging method of the present invention;

[0071] Figure 2 Flowchart of an embodiment of the batch packaging method of the present invention;

[0072] Figure 3 This is a principle block diagram of the packaging device in the present invention;

[0073] Figure 4 is a cross-sectional view of a first example of a MEMS electric field sensor after packaging in the present invention;

[0074] Figure 5 FIG. 4 is a cross-sectional view of a second example of a MEMS electric field sensor after packaging according to the present invention.

[0075] The main reference numerals are as follows:

[0076] 1-Packaging cover; 100-Positioning protrusion; 101-Mating portion; 2-Electric field sensitive chip; 3-Packaging shell;

[0077] 300 - frame-shaped boss; 301 - bonding area; 4 - lead; 5 - soldering point; 6 - valveable solder ring; 7 - inner core. DETAILED DESCRIPTION

[0078] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0079] In the description of the present invention, it should be understood that the terms "upper", "lower", "top surface", "bottom surface", "inside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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 of the present invention. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a centrally arranged component at the same time. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0080] Example 1

[0081] like Figure 1 As shown, this embodiment provides a batch packaging method for MEMS electric field sensors, including the following steps:

[0082] S1. Fixing a qualified electric field sensitive chip on the inner end surface of the package shell, including:

[0083] Check the electric field sensitive chips and screen out the electric field sensitive chips that do not meet the preset conditions;

[0084] Plasma cleaning of the package cover and package shell;

[0085] The electric field sensitive chip that meets the preset conditions is superimposed on the bonding area formed on the inner end surface of the package tube shell. After the glue is baked and cured, the electric field sensitive chip is fixed to the central area of ​​the inner end surface of the package tube shell.

[0086] S2. Connect the electric field sensitive chip to the designated solder joint through the lead wire, and test whether the pull force of the lead wire and the push force of the gold ball meet the requirements;

[0087] S3. Pre-process the package cavity, package cover, package shell and material box to meet the requirements before welding, including:

[0088] After the packaging cover plate and the qualified packaging tube are placed in the material box, they are put into the packaging cavity;

[0089] The water and oxygen content inside the packaging cavity is adjusted to a preset value, and the vacuum degree is adjusted to a specified micro-negative pressure state;

[0090] The water vapor and impurities on the packaging cover plate, the packaging tube and the material box are removed;

[0091] S4, in the packaging cavity, the packaging cover plate and the packaging tube are seam welded to fix the packaging cover plate on the packaging tube, and the qualified MEMS electric field sensor is stored, wherein it comprises:

[0092] The packaging cover plate is positioned and pressed on the top end surface of the packaging cover plate, and the parallel seam welding between the packaging cover plate and the packaging tube is carried out. After the valve welding ring is melted, the packaging cover plate is fixed on the packaging tube;

[0093] Check whether the welded MEMS electric field sensor meets the requirements, and store the MEMS electric field sensor that meets the requirements.

[0094] Embodiment two

[0095] As shown in Figure 2 , the embodiment provides a batch packaging method of MEMS electric field sensor, comprising the following steps:

[0096] S101, judging whether the electric field sensitive chip meets the requirements according to the preset condition.

[0097] Specifically, a plurality of electric field sensitive chips are sequentially placed in the jig of the wafer detection device, and the wafer detection device checks the structure of the electric field sensitive chip according to the preset condition. If the comb structure or other parts of the electric field sensitive chip do not meet the requirements, the current electric field sensitive chip is determined as a defective product and is marked to form a Mapping map.

[0098] Wherein, the Mapping is a map on the wafer, and the internal chips of a certain number are marked good or bad by detecting the digital code, such as 1-2-3-4, 1 represents good, and 2-3-4 represents chips with different defects.

[0099] Further, when it is determined that the current electric field sensitive chip does not meet the preset condition, the electric field sensitive chip that does not meet the preset condition can be removed by a mechanical arm or introduced into a machine table by a digital marker to automatically pick up the chip.

[0100] Exemplarily, the preset condition includes, but is not limited to, whether the size of the adjacent two combs is the same, and whether the spacing of each part of the adjacent two combs is the same.

[0101] Since the volume of the electric field sensitive chip is small, the wafer detection equipment can accurately and quickly screen out the electric field sensitive chip that does not meet the requirements, so as to improve the yield of the packaged electric field sensor.

[0102] S102, the packaging cover plate and the packaging tube shell are subjected to plasma cleaning.

[0103] Specifically, the packaging cover plate and the packaging tube shell are placed in the ultrasonic cleaning device filled with plasma, and the packaging cover plate and the packaging tube shell are cleaned by plasma under high temperature and high pressure to remove the organisms on the surface of the packaging cover plate and the packaging tube shell, improve the reliability of the packaging cover plate and the packaging tube shell, and avoid the influence of impurities or other substances on the comb structure in the electric field sensitive chip.

[0104] Further, the cleaning power of the packaging cover plate and the packaging tube shell is 100W-500W, the cleaning time is 2min-10min, the cleaning temperature is 30℃-80℃, the cleaning pressure value is 0.2-0.5kpa, and the gas in the cleaning process is argon-hydrogen mixed gas with a ratio of 95%-5%. The angle of the ceramic water drop angle can be reduced from the existing 45° to below 20°.

[0105] Further, the packaging cover plate or the packaging tube shell can be cleaned separately by the ultrasonic cleaning device, or the packaging cover plate and the packaging tube shell can be cleaned simultaneously.

[0106] Exemplarily, when the ultrasonic cleaning device cleans the packaging cover plate alone, the cleaning power is 200W, the cleaning time is 5min, the cleaning temperature is 30℃, and the cleaning pressure value is 0.2bar. When the ultrasonic cleaning device cleans the packaging tube shell alone, the cleaning power is 300W, the cleaning time is 3min, the cleaning temperature is 50℃, and the cleaning pressure value is 0.4bar. When the ultrasonic cleaning device cleans the packaging cover plate and the packaging tube shell simultaneously, the cleaning power is 300W, the cleaning time is 6min, the cleaning temperature is 60℃, and the cleaning pressure value is 0.5bar.

[0107] S103, dispensing glue on the specified position of the inner end face of the packaging tube shell to form a bonding area.

[0108] Specifically, the cleaned packaging tube shell is placed in the carrier of the die bonding equipment and pushed into the track by the push rod through the push rod. When the packaging tube shell is located below the glue dispenser, the glue dispenser dispenses glue on the inner end face of the packaging tube shell or draws glue to form a bonding area for fixing the electric field sensitive chip.

[0109] When the bonding area is formed by multiple separate glue points, each glue point will not overflow inward to avoid affecting the electric field sensitive chip.

[0110] When the adhesive area is formed by painting glue, the shape can be a self-defined pattern.

[0111] Optionally, when the adhesive area is formed by a plurality of individual glue points, each glue point is a circular glue point with a diameter in the range of 0.1-0.3 mm. By such a provision, the adverse effects and the resulting reduction in efficiency caused by glue stringing, glue throwing, and glue overflow can be avoided.

[0112] S104, superimpose the electric field sensitive chip meeting the preset condition on the adhesive area.

[0113] Specifically, the wafer detection device is used to detect the electric field sensitive chip meeting the requirements, and the electric field sensitive chip is placed on the adhesive area.

[0114] After the electric field sensitive chip is placed on the adhesive area, the inclination Z-axis value is within 15 um.

[0115] S105, check the offset and inclination of the electric field sensitive chip on the adhesive area to ensure that the electric field sensitive chip meets the requirements of the patch.

[0116] Specifically, the three-axis industrial microscope is used to check the offset and inclination of the electric field sensitive chip on the adhesive area, so as to ensure that the electric field sensitive chip is located in the central region of the inner end surface of the packaging tube shell and is kept horizontal.

[0117] Optionally, the three-axis industrial microscope can check the offset and inclination of each electric field sensitive chip one by one, or check the offset and inclination of one or several electric field sensitive chips.

[0118] S106, bake the packaging tube shell with the electric field sensitive chip placed therein to fix the electric field sensitive chip inside the packaging tube shell.

[0119] Specifically, after determining that the offset and inclination of the electric field sensitive chip meet the above requirements, the packaging tube shell with the electric field sensitive chip superimposed thereon is placed inside the magazine, and the magazine is placed in the baking equipment. After the glue is cured by baking, the electric field sensitive chip is fixed to the central region of the inner end surface of the packaging tube shell.

[0120] During baking, the baking temperature and baking time are adjusted according to the heating parameters corresponding to the glue, so that the glue points are cured and stick to the electric field sensitive chip, which can withstand the influence of different changes such as temperature and humidity, corrosion, and high and low temperature.

[0121] S107, check whether the fixing performance of the electric field sensitive chip meets the requirements.

[0122] Specifically, the fixed electric field sensitive chip is tested by a large range push-pull force testing machine to determine the fixing performance of the electric field sensitive chip in the packaging tube shell, thereby enhancing the reliability.

[0123] Further, the push-pull force testing machine can check the fixing performance of the electric field sensitive chip in the packaging tube shell one by one, or check the fixing performance of each electric field sensitive chip in each packaging tube shell according to the parameters of the push-pull force testing machine.

[0124] Preferably, the fixed electric field sensitive chip is tested by a 50kg push knife to determine whether the fixing performance of the electric field sensitive chip in the packaging tube shell meets the requirements of GJB548B-2005, thereby enhancing the reliability.

[0125] S108, the electric field sensitive chip is connected to the specified solder point through the lead.

[0126] Specifically, after determining that the fixing performance of the electric field sensitive chip meets the above requirements, the magazine is placed at the feeding end of the wire bonding machine, and the first end of the lead is connected to the specified solder point in the packaging tube shell through the wire bonding machine, and the second end of the lead is connected to the electric field sensitive chip.

[0127] Further, the packaging tube shell is placed into the wire bonding machine through the magazine push rod by the carrier pressure plate method.

[0128] In step S108, the magazine can be shared in the wire bonding machine, and batch packaging can be achieved.

[0129] S109, detecting whether the pull force of the lead and the push force of the gold ball meet the requirements.

[0130] Specifically, a first testing device is used to detect whether the pull force of the lead and the push force of the gold ball meet the requirements, thereby improving the yield. If it is determined that the pull force of the lead and the push force of the gold ball do not meet the requirements, they are rejected.

[0131] Alternatively, a lead pull force measuring instrument can be used to detect whether the pull force of the lead meets the requirements, a gold ball push force testing instrument can be used to detect whether the push force of the gold ball meets the requirements, or a gold wire push-pull force device can be used to detect whether the pull force of the lead and the push force of the gold ball meet the requirements.

[0132] S110, ensuring that the water and oxygen content inside the packaging cavity reaches a preset value, and the vacuum degree is in a specified micro-negative pressure state.

[0133] Specifically, the following steps are included:

[0134] Placing a plurality of magazines with packaging tube shells having built-in packaging cover plates and fixed electric field sensitive chips in the packaging cavity;

[0135] Injecting nitrogen into the packaging cavity through a nitrogen machine, and vacuumizing the inside of the packaging cavity through a vacuumizing device;

[0136] Repeating the above steps until the water-oxygen content in the inside of the packaging cavity reaches a preset value, and the vacuum degree is in a specified micro-negative pressure state.

[0137] Preferably, the preset value of the water-oxygen content is that the water vapor dew point value is less than -50℃, and the oxygen content is less than 10ppm, and the specified micro-negative pressure state is less than 1 standard atmosphere.

[0138] Preferably, the preset value of the water-oxygen content is that the water vapor dew point value is -60℃, and the oxygen content is 5ppm.

[0139] Preferably, the parameter of the vacuumizing device outside is set to be less than 50pa, and the inside of the packaging cavity is vacuumized, so that the micro-negative pressure state of the inside of the packaging cavity is 0.1-0.5kpa.

[0140] Further, the nitrogen machine is used to continuously or intermittently inject nitrogen with a purity of 99.999% into the pre-baking packaging cavity. Compared with the prior art of injecting nitrogen into the packaging cavity by using multiple gas cylinders, the phenomenon of increasing water-oxygen content in the packaging cavity caused by replacing the gas cylinders can be avoided since the gas cylinders do not need to be replaced.

[0141] S111, removing water vapor and impurities on the packaging cover plate, the packaging tube shell and the cartridge in the packaging cavity.

[0142] Specifically, the mixed gas in the packaging cavity is extracted by the vacuumizing device, so that the inside of the packaging cavity is in a specified micro-negative pressure state, the heating device preheats from the current temperature value to the set temperature value according to a preset temperature rising time threshold, and maintains the set temperature value for a preset time value, wherein the preset temperature rising time threshold is at least 30-45 minutes, the set constant temperature value is at least 200℃, and the preset time value is at least 120 minutes.

[0143] Further, the impurities on the packaging cover plate and the packaging tube shell are water vapor, dust, particles and organic matter.

[0144] Optionally, in steps S110 and S111, the nitrogen machine, the vacuumizing device and the heating device are operated at least 3 times, that is, the nitrogen machine fills the inside of the packaging cavity with nitrogen of a set concentration, the vacuumizing device extracts all the mixed gas (including nitrogen, water vapor, etc.) in the packaging cavity at a set pressure, and the heating device heats the inside of the packaging cavity according to a set heating parameter, so that the inside of the packaging cavity meets the water-oxygen content requirement. After step S111 is completed, the temperature of the packaging cover plate and the packaging tube shell is lowered to room temperature.

[0145] Further, the time threshold required for the temperature of the packaging cover plate and the packaging shell to drop to room temperature is 30 to 45 minutes.

[0146] S112, welding the packaging cover plate and the packaging shell, and fixing the packaging cover plate on the packaging shell.

[0147] Specifically, when the inside of the packaging cavity is in a specified micro-negative pressure state, the packaging cover plate is positioned and covers the top end surface of the packaging shell by the positioning protrusion, the packaging cover plate is pressed by the clamp, and parallel seam welding is performed on the area between the packaging cover plate and the packaging shell by the parallel seam welding machine. After ensuring that the valve weld ring is melted, the packaging cover plate is fixed on the packaging shell.

[0148] Further, the welding temperature is selected according to the material of the valve weld ring, and after ensuring that the valve weld ring is melted, the packaging cover plate is fixed on the packaging shell.

[0149] S113, judging whether the fixed position of the packaging cover plate on the packaging shell after welding meets the requirements.

[0150] Specifically, the visual recognition device checks the fixed position of the packaging cover plate on the packaging shell after welding by a positioning algorithm and a PR recognition method, and judges whether the edge end surface of the packaging cover plate and the outer wall surface of the packaging shell are in the same plane. If they are in the same plane, it indicates that the position of the packaging cover plate meets the requirements, and if they are not in the same plane, it indicates that the position of the packaging cover plate does not meet the requirements, and it needs to be rejected, thereby improving the yield.

[0151] S114, judging whether there is a leak point at the welding position between the packaging cover plate and the packaging shell.

[0152] Specifically, a fluorine oil helium mass spectrometer leak detector is used to judge whether there is a leak point at the welding position between the packaging cover plate and the packaging shell. If there is no leak point, it indicates that the welding position between the packaging cover plate and the packaging shell meets the requirements, and if there is a leak point, it indicates that the welding position between the packaging cover plate and the packaging shell does not meet the requirements, and it needs to be rejected, thereby improving the yield.

[0153] Further, the welded MEMS electric field sensor is placed in a fluorine oil platform, and whether there is a leak point position at the welding position is confirmed by the boiling point of light and heavy fluorine oil.

[0154] S115, testing whether the performance of the MEMS electric field sensor meets the packaging requirements.

[0155] Specifically, the MEMS electric field sensor after welding is connected with the second testing device, the second testing device collects and analyzes the output signal of the MEMS electric field sensor, so as to form a sweep frequency calibration curve and test data, and determine whether the performance of the MEMS electric field sensor meets the performance requirement according to the sweep frequency calibration curve and the test data. If the test data is within the preset threshold range, it indicates that the performance of the MEMS electric field sensor meets the requirement, and if the test data is not within the preset threshold range, it indicates that the performance of the MEMS electric field sensor does not meet the requirement, and it needs to be rejected, thereby improving the yield.

[0156] Optionally, the performance of the MEMS electric field sensor includes, but is not limited to, the sensitivity, air pressure value, air tightness, etc. inside the MEMS electric field sensor.

[0157] Preferably, the second testing device adopts a sweep frequency calibration device. After the MEMS electric field sensor is connected with the sweep frequency calibration device, the output signal of the MEMS electric field sensor is collected and analyzed, so as to form a sweep frequency curve and test data, and determine whether the performance of the MEMS electric field sensor meets the packaging requirement according to the sweep frequency calibration curve and the test data, thereby improving the yield.

[0158] S116, after printing product information on the MEMS electric field sensor meeting the performance requirement, the finished product is warehoused.

[0159] Specifically, a laser coding machine is used to print product information on the MEMS electric field sensor meeting the packaging requirement.

[0160] S117, after completing the printing of product information, the finished product is warehoused.

[0161] Embodiment three

[0162] As shown in Figure 3 , the present embodiment provides a packaging equipment for the packaging method described in the above embodiment one or embodiment two, which comprises a wafer detection equipment, an ultrasonic cleaning device, a dispensing mechanism, a patching mechanism, a three-axis industrial microscope, a baking equipment, a push-pull force testing machine, a wire bonding machine, a first testing device, a nitrogen machine, a vacuumizing equipment, a heating equipment, a parallel seam welding machine, a visual recognition device, a fluorine oil helium mass spectrometer leak detector, a second testing device and a laser coding machine.

[0163] The wafer detection equipment is used to implement the step in S101, and determines whether the electric field sensitive chip meets the preset condition according to the preset condition. When it is determined that the current electric field sensitive chip does not meet the preset condition, a Mapping diagram is generated according to the determination result, and the electric field sensitive chip not meeting the preset condition is rejected through a mechanical arm.

[0164] The ultrasonic cleaning device is used to implement the step in S102, and plasma cleaning is performed on the packaging cover plate and the packaging tube shell under high temperature and high pressure to remove the organisms on the surfaces of the packaging cover plate and the packaging tube shell, so as to avoid the influence of impurities on the comb structure in the electric field sensitive chip.

[0165] The dispensing mechanism is used to implement the step in S103, and the bonding area for bonding the electric field sensitive chip is formed at the specified position of the inner end surface of the packaging tube shell.

[0166] The patching mechanism is used to implement the step in S104, and the required electric field sensitive chip is stacked on the bonding area.

[0167] The three-axis industrial microscope is used to implement the step in S105, and the offset and the tilt angle of the electric field sensitive chip on the bonding area are checked to ensure that the electric field sensitive chip meets the patching requirements.

[0168] The baking equipment is used to implement the step in S106, and the packaging tube shell with the electric field sensitive chip is baked, and after the glue is cured by baking, the electric field sensitive chip is fixed in the central area inside the packaging tube shell.

[0169] Preferably, the baking equipment can be an oven.

[0170] The push-pull force testing machine is used to implement the step in S107, and the fixing performance of the electric field sensitive chip is checked to determine whether it meets the requirements.

[0171] The wire bonding machine is used to implement the step in S108, and the electric field sensitive chip is connected to the specified bonding point through the lead wire. After the wire bonding, the first end of the lead wire is connected to the specified bonding point, and the second end of the lead wire is connected to the electric field sensitive chip.

[0172] The first testing device is used to implement the step in S109, and the tension of the lead wire and the thrust of the gold ball are detected to determine whether they meet the requirements.

[0173] The nitrogen gas machine cooperates with the vacuum pumping equipment to implement the step in S110, and nitrogen gas is injected into the packaging cavity through the nitrogen gas machine, and the inside of the packaging cavity is pumped to vacuum through the vacuum pumping equipment. After repeating the above operation for multiple times, the water and oxygen content inside the packaging cavity reaches the preset value, and the vacuum degree is in the specified micro-negative pressure state.

[0174] Preferably, the packaging cavity is a glove box.

[0175] The heating equipment is used to implement the step in S111, and the inside of the packaging cavity is heated to a set temperature value and maintained at the set temperature value for a preset time value, so as to remove the water vapor and impurities on the packaging cover plate, the packaging tube shell and the cartridge in the packaging cavity.

[0176] The parallel seam welding machine is used to implement the steps in S112 above, welding the package cover plate to the package shell, and fixing the package cover plate on the package shell.

[0177] The visual recognition device is used to implement the step in S113 above to determine whether the fixed position of the package cover plate on the package shell meets the requirements after welding.

[0178] The fluorine oil helium mass spectrometer leak detector is used to implement the step in S114 above to determine whether there is a leak at the welding point between the packaging cover plate and the packaging tube shell.

[0179] The second testing device is used to implement the step in S115 above to determine whether the performance of the MEMS electric field sensor meets the packaging requirements.

[0180] The laser coding machine is used to implement the steps in the above S116 and print product information on the MEMS electric field sensor that meets the performance requirements.

[0181] After the product information is printed, the finished product is put into storage.

[0182] In this embodiment, the wafer detection equipment, ultrasonic cleaning device, dispensing mechanism, patch mechanism, three-axis industrial microscope, baking equipment, and push-pull force testing machine form the electric field sensitive chip fixing part, the wire bonding machine and the first testing device form the wire bonding testing part, the nitrogen machine, vacuum equipment and heating equipment form the pretreatment part, and the parallel seam welding machine, visual recognition device, fluorine oil helium mass spectrometer leak detector and the second testing device form the welding testing part.

[0183] Example 4

[0184] like Figure 4 As shown, this embodiment provides a MEMS electric field sensor, including a packaging cover plate 1, a packaging tube shell 3 and an electric field sensitive chip 2. The packaging cover plate 1 and the packaging tube shell 3 are fixed to form a packaging structure of the electric field sensitive chip 2 and provide space for fixing the electric field sensitive chip 2. The electric field sensitive chip 2 is fixed inside the packaging tube shell 3.

[0185] The package cover 1 is made of metal material, and the package shell 3 is made of non-metal material, which can be ceramic material, plastic material or other non-metal material.

[0186] Specifically, in the package cover plate 1 , a local area of ​​the bottom end surface thereof is recessed toward the top end surface of the package cover plate 1 , thereby forming a positioning protrusion 100 and a matching portion 101 surrounding the positioning protrusion 100 .

[0187] Furthermore, the thickness of the positioning protrusion 100 is 0.25 mm, and the thickness of the matching portion 101 is 0.1 mm.

[0188] Further, the bottom end surface of the positioning protrusion 100 is horizontally structured, and an inner core 7 is arranged on the bottom end surface of the positioning protrusion 100, wherein the inner core 7 comprises an inner protruding end extending downward and adjacent to the electric field sensitive chip 2.

[0189] Further, the axis of the inner core 7 is on the same longitudinal axis as the axis of the positioning protrusion 100.

[0190] Specifically, after the package cover plate 1 is buckled on the top end surface of the package tube shell 3, the positioning protrusion 100 is arranged in the space, the side wall surface of the positioning protrusion 100 is adjacent to the inner side of the side wall of the package tube shell 3, and the bottom end surface of the fitting part 101 is superimposed on the top end surface of the valve solderable ring 6. When the valve solderable ring 6 reaches the melting point and melts, the package cover plate 1 is buckled and fixed on the open end surface of the package tube shell 3, and the outer side wall surface of the package cover plate 1 is in the same plane as the outer side wall surface of the package tube shell 3.

[0191] The central region of the inner end surface of the package tube shell 3 is covered with an adhesive region 301, the electric field sensitive chip 2 is superimposed on the upper position of the adhesive region 301, and the electric field sensitive chip 2 is fixed in a horizontal manner on the central region of the inner end surface of the package tube shell 3 through the solidified adhesive.

[0192] Further, the local region of the inner end surface of the package tube shell 3 extends upward to form a frame-shaped boss 300, which surrounds the outside of the adhesive and forms a placement region of the electric field sensitive chip 2 between the inner end surface of the package tube shell 3.

[0193] Further, a plurality of through holes are arranged at intervals on the inner end surface of the package tube shell 3, each through hole extends upward and penetrates the inside of the frame-shaped boss 300, the plurality of through holes surround the outside of the adhesive region 301 to form a through hole region. Each solder joint 5 penetrates the inside of the through hole in turn, so that the top end surface of each solder joint 5 is located above the frame-shaped boss 300 and in the space, and the bottom end surface of each solder joint 5 is located below the package tube shell 3 and can be connected to the external circuit board.

[0194] When the top end surface of the solder joint 5 is located in the space, the top end surface of each solder joint 5 is in the same plane as the top end surface of the electric field sensitive chip 2. The top end surface of each designated solder joint 5 is electrically connected to the electric field sensitive chip 2 through the lead 4, so that the electric field sensitive chip 2 is connected to the external circuit board through the leads 4, can receive relevant signals input by the external circuit board, or input relevant signals to the external circuit board.

[0195] Example Five

[0196] As Figure 5As shown, the embodiment provides a MEMS electric field sensor, which is different from the MEMS electric field sensor described in the above embodiment four in structure.

[0197] The inner core 7 includes an inner convex end extending vertically downward and adjacent to the electric field sensitive chip 2, and an upper end extending vertically upward through the inside of the packaging cover plate 1 and located above the packaging cover plate 1.

[0198] In the above embodiment one and embodiment two, the packaging cover plate is made of Kovar alloy material, the packaging tube shell is made of composite ceramic material of 90% alumina, the valve welding ring is 4J29 alloy, and the inner core 7 is made of conductive material.

[0199] In the above embodiment four and embodiment five, the positioning protrusion is additionally arranged on the bottom end face of the packaging cover plate, and the width of the positioning protrusion is adjacent to the width of the open end face in the packaging tube shell, so as to facilitate positioning the buckling position of the packaging cover plate, so that the position of the packaging cover plate placed on the packaging tube shell cannot be deviated, and after the valve welding ring is melted, the packaging cover plate is ensured to cover the top end of the valve welding ring, and the air tightness of the packaged MEMS electric field sensor is ensured.

[0200] The above is only the preferred embodiment of the present application, which is only illustrative but not limiting. It is understood by those skilled in the art that many changes, modifications and even equivalents can be made to the present application within the spirit and scope defined by the claims of the present application, and all shall fall within the protection scope of the present application.

Claims

1. A batch packaging method for MEMS electric field sensors, characterized in that: The following steps are involved: S1. Fixing a qualified electric field sensitive chip on the inner end surface of the package shell, including: checking the electric field sensitive chips and screening out the electric field sensitive chips that do not meet preset conditions; performing plasma cleaning on the packaging cover plate and the packaging shell; Overlaying the electric field sensitive chip that meets preset conditions on the bonding area formed on the inner end surface of the package tube shell, and after the glue is baked and cured, the electric field sensitive chip is fixed to the central area of ​​the inner end surface of the package tube shell; S2. Connect the electric field sensitive chip to the designated solder joints through wires, and detect whether the pulling force of the wires and the pushing force of the gold balls meet the requirements; S3. Pre-process the package cavity, package cover, package shell and material box to meet the requirements before welding, including: Place the packaging cover plate and the packaging shell that meets the requirements in a material box, and then place them into the packaging cavity; Adjusting the water and oxygen content inside the packaging cavity to a preset value and the vacuum degree to a specified slightly negative pressure state; Removing moisture and impurities from the packaging cover plate, the packaging tube shell, and the material box; S4. In the packaging cavity, seam welding the packaging cover plate and the packaging shell to fix the packaging cover plate on the packaging shell, and storing the MEMS electric field sensors that meet the requirements, including: Positioning and pressing the package cover plate onto the top end surface of the package cover plate, performing parallel seam welding between the package cover plate and the package shell, and fixing the package cover plate on the package shell after the valve welding ring is melted; Check whether the welded MEMS electric field sensor meets the requirements, and put the MEMS electric field sensor that meets the requirements into storage.

2. The batch packaging method of MEMS electric field sensors according to claim 1, characterized in that: The process of stacking the electric field sensitive chip that meets the preset conditions on the bonding area formed on the inner end surface of the package tube shell, and fixing the electric field sensitive chip in the central area of ​​the inner end surface of the package tube shell after the glue is baked and cured, includes: forming a bonding area for the electric field sensitive chip at a designated position on the inner end surface of the package shell; superimposing the electric field sensitive chip that meets the preset conditions on the bonding area; Checking the offset and tilt angle of the electric field sensitive chip on the bonding area to ensure that the electric field sensitive chip meets the patch requirements; Baking the package tube shell in which the electric field sensitive chip is placed, and fixing the electric field sensitive chip inside the package tube shell after the glue is cured by baking; Check whether the fixing performance of the electric field sensitive chip meets the requirements.

3. The batch packaging method of MEMS electric field sensors according to claim 1, characterized in that: After the electric field sensitive chip is connected to a designated solder joint via a lead, the performance of the pull force of the lead and the push force of the gold ball are tested, including: placing the package shell into a wire bonding machine so that the first end of the lead is connected to a designated solder joint of the package shell, and the second end of the lead is connected to the electric field sensitive chip; Check whether the pulling force of the lead and the pushing force of the gold ball meet the requirements.

4. The batch packaging method of MEMS electric field sensors according to claim 1, characterized in that: The step of adjusting the water and oxygen content inside the packaging cavity to a preset value and the vacuum degree to a specified slightly negative pressure state includes: Injecting nitrogen into the packaging cavity and evacuating the interior of the packaging cavity; After repeated several times, the water and oxygen content inside the packaging cavity reaches a preset value and the vacuum degree is in a specified micro-negative pressure state, wherein: The preset value of water oxygen content is water vapor dew point value of -60℃, oxygen content is less than 5ppm, and the specified micro-negative pressure state is less than 1 standard atmosphere.

5. The batch packaging method of MEMS electric field sensors according to claim 4, characterized in that: The step of removing moisture and impurities from the packaging cover plate, the packaging tube shell, and the material box includes: The interior of the packaging cavity is heated to a set temperature value according to a preset temperature rise time threshold under a specified slightly negative pressure state, and the set temperature value is maintained for a preset time value, wherein: The preset heating time threshold is 30 to 45 minutes, the set constant temperature value is at least 200°C, and the preset time value is at least 120 minutes.

6. The batch packaging method of MEMS electric field sensors according to claim 1, characterized in that: In the packaging cavity, the packaging cover plate and the packaging shell are seam-welded to fix the packaging cover plate on the packaging shell, and the MEMS electric field sensors that meet the requirements are stored in the warehouse, including: Determining whether the fixed position of the package cover plate on the package shell meets the requirements after welding; Determining whether there is a leak at the welding point between the packaging cover plate and the packaging tube shell; Test whether the performance of the MEMS electric field sensor meets the packaging requirements.

7. A packaging device, characterized in that: A batch packaging method for implementing the MEMS electric field sensor according to any one of claims 1 to 6, comprising an electric field sensitive chip fixing part, a wire bonding test part, a pre-processing part, and a welding test part, wherein: The electric field sensitive chip fixing part is used to fix the electric field sensitive chip that meets the requirements on the inner end face of the package shell, including wafer detection equipment, ultrasonic cleaning equipment, fixing equipment and wire bonding testing equipment: The wafer detection device is used to determine whether the electric field sensitive chip meets the preset conditions according to the preset conditions, and form a mapping diagram based on the electric field sensitive chip that does not meet the preset conditions; The ultrasonic cleaning device is used to perform plasma cleaning on the packaging cover plate and the packaging shell; The fixing device is used to superimpose the electric field sensitive chip that meets the preset conditions on the bonding area formed on the inner end surface of the package tube shell, and after the glue is baked and cured, the electric field sensitive chip is fixed to the central area of ​​the inner end surface of the package tube shell; The wire bonding test section is used to connect the electric field sensitive chip and the designated solder joint through the lead wire and detect whether the pulling force of the lead wire and the pushing force of the gold ball meet the requirements, including a wire bonding machine and a first testing device, wherein: The wire bonding machine is used to connect the first end of the lead to a designated solder joint in the package shell, and to connect the second end of the lead to the electric field sensitive chip; The first testing device is used to test whether the electrical performance between the electric field sensitive chip, the lead and the designated solder joint meets the requirements; The pre-processing part is used to pre-process the packaging cavity, the packaging cover plate, the packaging tube shell and the material box that meet the requirements to meet the requirements before welding; The welding test part is used in the packaging cavity to seam weld the packaging cover plate and the packaging shell to fix the packaging cover plate on the packaging shell and store the MEMS electric field sensors that meet the requirements. It includes a parallel seam welder and a testing device, wherein: The parallel seam welding machine is used to perform parallel seam welding between the packaging cover plate and the packaging tube shell, and after the valve welding ring is melted, the packaging cover plate is fixed on the packaging tube shell; The testing device is used to check whether the welded MEMS electric field sensor meets the requirements.

8. The packaging device according to claim 7, characterized in that The fixing device includes a dispensing mechanism, a patch mechanism, a three-axis industrial microscope, a baking device and a push-pull force testing machine, wherein: The glue dispensing mechanism is used to dispense glue at a designated position on the inner end surface of the package tube shell to form a bonding area; The patch mechanism is used to superimpose the electric field sensitive chip that meets the requirements on the bonding area; The three-axis industrial microscope is used to check the offset and tilt angle of the electric field sensitive chip on the bonding area to ensure that the electric field sensitive chip meets the patch requirements; The baking device is used to bake the package tube shell in which the electric field sensitive chip is placed, and after the glue is cured by baking, the electric field sensitive chip is fixed in the central area inside the package tube shell; The push-pull force testing machine is used to check whether the fixing performance of the electric field sensitive chip meets the requirements.

9. The packaging device according to claim 7, wherein: The pretreatment part includes a nitrogen machine, a vacuum pumping device and a heating device, wherein: The nitrogen generator is used to inject nitrogen into the packaging cavity; The vacuum pumping device is used to extract the mixed gas in the packaging cavity so that the water and oxygen content inside the packaging cavity reaches a preset value and the vacuum degree is in a specified slightly negative pressure state; The heating device is used to heat the internal temperature of the packaging cavity to a set temperature value according to a preset heating time threshold, and maintain the set temperature value for a preset time value to remove moisture and impurities on the packaging cover plate, the packaging tube shell and the material box.

10. The packaging device according to claim 7, wherein: The testing device includes a visual recognition device, a fluorine oil helium mass spectrometer leak detector and a second testing device, wherein: The visual recognition device is used to determine whether the fixed position of the package cover plate on the package shell meets the requirements after welding; The fluorine oil helium mass spectrometer leak detector is used to determine whether there is a leak at the welding point between the packaging cover plate and the packaging tube shell; The second testing device is used to determine whether the performance of the MEMS electric field sensor meets packaging requirements.

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