MEMS gas sensor wafer microfabrication and testing system and method

Abstract

The application discloses a MEMS gas sensor wafer microprocessing and testing system and method. The system comprises a rack, wherein an operation platform, a spotting system, a testing system, a dicing system, a spotting station, a testing station, a dicing station, a driving device, a visual system and a control unit are arranged on the rack; the spotting system, the testing system, the dicing system, the driving device and the visual system are electrically connected with the control unit; and the driving device can drive the operation platform to move to the spotting station, the testing station and the dicing station respectively. The method comprises wafer position correction, Maping graph formation, spotting, testing and dicing. The application has the advantages that the MEMS gas sensor wafer can be coated with a gas-sensitive material, detected and cut, and the overall cost is relatively low.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of MEMS gas sensor, in particular to a MEMS gas sensor wafer micro-machining and testing system and method. BACKGROUND

[0002] With the rise of the concept of the Internet of Things, the demand for gas sensors that simulate human olfaction has also increased significantly in recent years. Currently, the gas sensors used in the market are mostly semiconductor gas sensors and catalytic combustion gas sensors. Both of them are heated to a state that can sense changes in the external gas by heating the material. The traditional heating method is to heat the platinum wire winding. The mass production of sensors requires a lot of manpower, and the production efficiency is low. Due to the different technical abilities of workers, the consistency and yield of the products are reduced. Micro-Electro-Mechanical System (MEMS) micro-heating chips based on semiconductor technology have attracted widespread attention in the field of gas sensors due to their small size, low power consumption, low cost, and easy integration. MEMS micro-heating chips use sputtering, deposition, etching, lithography, and slicing to manufacture heating elements and measurement circuits on a silicon plane. The silicon-based heater realizes the detection performance of the gas sensor. Semiconductor and catalytic combustion sensors based on MEMS technology greatly achieve miniaturization and low power consumption. At the same time, the batch production process based on this technology has also been greatly simplified.

[0003] After the chip processing is completed, the gas-sensitive material needs to be coated in the heating area. There is still no public report in the industry. The mainstream process in the academic field uses the inkjet printing method, but the ink dots are difficult to control, and the slurry requirements for printing are very high, only suitable for some low-viscosity slurry, and do not meet the needs of industrial production. In the prior art, for example, the Chinese patent application with publication number CN112162015A discloses an anti-gas interference type MEMS gas sensor and a preparation method, which is to deposit a layer of gas-sensitive material on the surface of the insulating layer by sputtering, PVD or spraying.

[0004] In addition, the detection of MEMS-based gas sensors still relies on large-scale wafer testing machines, which are mostly designed for the detection of complex chips such as CPUs and memory chips. The price is expensive. In addition, these expensive instruments cannot manage data specifically for sensors, and the wafer detection equipment on the market cannot test the sensitivity of gas sensors. Therefore, there is an urgent need for a wafer testing system for batch detection of MEMS gas sensors to screen good products after loading materials on sensor chips, which plays a crucial role in time, manpower, and material cost control in the subsequent sensor packaging process.

[0005] After testing the sensor chip, the entire wafer needs to be cut. Since the gas-sensitive material on the sensor cannot come into contact with water, laser cutting is the only option. Prior art, for example, Chinese invention patent publication number CN107529467A discloses a multi-focus laser cutting system and method for silicon-based MEMS wafers, which utilizes laser cutting.

[0006] Currently, the three processes of coating gas-sensitive materials, testing, and cutting need to be completed on three different machines. Moreover, the prices of these three devices are relatively high and require large firmware costs. Summary of the Invention

[0007] The technical problems to be solved by the present invention are:

[0008] The existing technology cannot take into account the technical problems of coating gas-sensitive materials, testing, and cutting of MEMS gas sensor wafers, and the overall cost is relatively high.

[0009] The present invention solves the above technical problems through the following technical means:

[0010] A MEMS gas sensor wafer micromachining and testing system includes a frame, on which are provided an operating platform, a sample spotting system, a test system, a dicing system, a sample spotting station, a test station, a dicing station, a drive device, a vision system, and a control unit;

[0011] The sample spotting system, test system, scribing system, drive device, and visual system are electrically connected to the control unit respectively; the drive device can drive the operating platform to move to the sample spotting station, test station, and scribing station respectively.

[0012] In practical applications, the MEMS gas sensor wafer micromachining and testing system of the present invention combines the three process steps involved in the MEMS gas sensor manufacturing process, including spotting, testing, and dicing, to form a micromachining and testing system for MEMS gas sensors, greatly reducing the firmware cost in mass production of sensors. The system can also identify whether the sample has been spotted through a visual system, and can resample some chips with poor quality spots to improve the yield rate. The test results are used for selective packaging of sensors, and subsequent operations are not performed on sensors that exceed the required range, greatly reducing the production cost of the sensor. The system takes into account the coating of gas-sensitive materials, testing, and dicing of MEMS gas sensor wafers, and the overall cost is relatively low.

[0013] Optimally, the driving device adopts a three-axis robotic arm, the movable end of which is provided with a rotating mechanism, and the three-axis robotic arm can drive the rotating mechanism to move in the horizontal plane and in the vertical direction;

[0014] The rotation axis of the rotating mechanism is along the vertical direction, and the operating platform is installed at the movable end of the rotating mechanism.

[0015] Under the action of the three-axis robotic arm and the rotating mechanism, the wafer can move in the horizontal plane and the vertical direction along with the operating platform, and can rotate around the vertical axis to meet the adjustment of the wafer position, and the movement is flexible and reliable.

[0016] Optimally, the test system includes a probe card rack disposed on a rack, wherein a probe card is disposed on the probe card rack;

[0017] It also includes an optical microscope arranged on a rack or a probe card rack, a CCD camera is arranged at the eyepiece of the optical microscope, the optical microscope can move in a horizontal plane and in a vertical direction, and the optical microscope can observe wafers and probe cards.

[0018] In actual application, the probe card and chip's needle placement can be verified through an optical microscope and CCD camera. The system records the relative position of the needle placement and repeats the same position on other chips to ensure detection accuracy. In addition, the optical microscope and CCD camera can also be used to observe the wafer dispensing status.

[0019] Optimally, the probe card rack is provided with an air outlet and an air intake, and the wafer can be moved between the air outlet and the air intake along with the operating platform.

[0020] The air outlet and air inlet are used for the sensitivity test of the sensor. During the test, the atmosphere to be tested is released from the air outlet. After the test, the clean air is discharged from the air outlet, and the air inlet absorbs the test atmosphere. The overall structure of the air outlet and air inlet is simple and easy to use, which can conveniently and quickly test the sensitivity of the sensor.

[0021] Optimally, the vision system includes a camera mounted on a frame in a vertical sliding manner.

[0022] The present invention also discloses a method using the above-mentioned MEMS gas sensor wafer micromachining and testing system, comprising the following steps:

[0023] S1. Wafer position correction

[0024] Correct the chip array on the wafer to a horizontal and vertical position;

[0025] S2. Forming a Mapping Graph

[0026] The system uses CAD drawings as its basis to form a mapping diagram. The mapping diagram is an array of blocks the size of a single chip, which are sorted. Each block in the mapping stores the chip's serial number, location information, and test results. The array is mapped to the actual chip position in the visual system, and any chip can be selected in the system for observation, testing, and material loading.

[0027] S3, spotting

[0028] The wafer moves with the operating platform to the spotting station, where the spotting system spots the wafer and dries it after spotting.

[0029] S4. Testing

[0030] The driving device drives the operating platform to move the wafer to the test station. When the test system tests the semiconductor sensor, it tests the heated resistance, cold resistance, chip adjacent pin resistance and the corresponding current and voltage. When the test system tests the catalytic combustion sensor, it tests the heating wire resistance and bridge bias voltage.

[0031] S5. Dicing

[0032] The driving device drives the operating platform to move the wafer to the dicing station, and the dicing system cuts the wafer.

[0033] Through the above method, the MEMS gas sensor wafer can be coated with gas-sensitive materials, tested, and cut. When the wafer position is corrected, the wafer can be accurately corrected to the predetermined position, thereby ensuring the accuracy of sampling, testing, and dicing. After the CAD drawing is input into the system, the system forms an array of blocks the size of a single chip, and sorts them according to requirements to form a Mapping diagram. The array can be matched with the actual chip position through the visual system. Any chip can be selected in the system for observation, testing, and material loading, and the operation is relatively convenient. The system can realize the testing of different types of sensors such as semiconductor sensors and catalytic combustion sensors, and the test range is relatively wide. Compared with the existing technology, it can take into account the three processes experienced in the production process of MEMS gas sensors, and is relatively simple and reliable as a whole.

[0034] Optimized, in step S1, after the wafer is placed on the operating platform, the driving device drives the operating platform to move the wafer, finds the characteristic points on the chip through the visual system, and corrects the chip array of the wafer to a horizontal and vertical position through the operating platform to perform wafer position correction.

[0035] Optimized, in step S3, the spotting system includes a piezoelectric jet valve and / or a pneumatic dispensing valve arranged on a frame; select jet spotting or dip spotting: when performing jet spotting through the piezoelectric jet valve, set the spotting height, that is, the distance between the chip and the valve port of the piezoelectric jet valve, determine the spotting position, set the piezoelectric jet valve parameters, and correct the state and position of the glue dot; when performing dip spotting through the pneumatic dispensing valve, determine the spotting position, set the spotting height and pneumatic dispensing valve parameters, and correct the state and position of the glue dot; then perform spotting.

[0036] Piezoelectric jet valves and pneumatic dispensing valves can meet the needs of dispensing sensitive material slurries with different viscosities. They can be set and selected according to actual needs. Piezoelectric jet valves or pneumatic dispensing valves can achieve jetting or dipping to meet different usage needs and have a wide range of applications.

[0037] Optimized, in step S4, the test system includes a probe card rack provided on a rack, the probe card being provided on the probe card rack; and further includes an optical microscope provided on the rack or the probe card rack, a CCD camera being provided at an eyepiece of the optical microscope, the optical microscope being capable of moving in a horizontal plane and in a vertical direction, and the optical microscope being capable of observing the wafer and the probe card;

[0038] First, proofreading is performed: the wafer moves to the test station along with the operating platform, and the probe position of the probe card and chip is first proofread using an optical microscope. The system records the relative position of the probe and then drops the probe at the same position on other chips. After proofreading, testing is performed. The test results are in Mapping format, containing all the test data, and can be converted to other formats such as Excel and TXT format data. At the same time, the system can read Mapping format data and add material to points with higher resistance.

[0039] The needle drop position can be checked through an optical microscope to ensure test accuracy.

[0040] Optimized, in step S5, the dicing system includes a laser set on a frame; the motion lines are drawn in CAD, and the motion path is automatically generated after importing. The dicing is based on the CAD drawing, and the wafer moves to the dicing station along with the operating platform. The laser point correction is performed through the visual system, and the wafer moves linearly along the operating platform according to the generated motion path, and the laser cuts the wafer.

[0041] The laser cutting method has a simple structure and principle and is easy to cut.

[0042] The advantages of the present invention are:

[0043] 1. In practical applications, the MEMS gas sensor wafer micromachining and testing system of the present invention combines the three process steps involved in the MEMS gas sensor manufacturing process, including spotting, testing, and dicing, to form a micromachining and testing system for MEMS gas sensors, greatly reducing the firmware cost in mass production of sensors. The system can also identify whether the sample has been spotted through a visual system, and can resample some chips with poor quality spots to improve the yield rate. The test results are used for selective packaging of sensors, and no subsequent operations are performed on sensors that exceed the required range, greatly reducing the production cost of the sensor. The system takes into account the coating of gas-sensitive materials, testing, and cutting of MEMS gas sensor wafers, and has a low overall cost.

[0044] 2. Under the action of the three-axis robotic arm and the rotating mechanism, the wafer can move in the horizontal plane and the vertical direction along with the operating platform, and can rotate around the vertical axis to meet the adjustment of the wafer position, and the movement is flexible and reliable.

[0045] 3. In actual application, the probe card and chip's needle placement position can be verified through an optical microscope and CCD camera. The system records the relative position of the needle placement and repeats the needle placement on other chips at the same position to ensure detection accuracy. In addition, the optical microscope and CCD camera can also be used to observe the wafer dispensing status.

[0046] 4. The air outlet and air inlet are used for the sensitivity test of the sensor. During the test, the atmosphere to be tested is released from the air outlet. After the test, the clean air is discharged from the air outlet, and the air inlet absorbs the test atmosphere. The overall structure of the air outlet and air inlet is simple and easy to use, which can conveniently and quickly test the sensitivity of the sensor.

[0047] 5. Through the above method, the MEMS gas sensor wafer can be coated with gas-sensitive materials, tested, and cut. When the wafer position is corrected, the wafer can be accurately corrected to the predetermined position, thereby ensuring the accuracy of sampling, testing, and dicing. After the CAD drawing is input into the system, the system forms an array of blocks the size of a single chip, and sorts them according to requirements to form a Mapping diagram. The array can be matched with the actual chip position through the visual system. Any chip can be selected in the system for observation, testing, and material loading, and the operation is relatively convenient. The system can realize the testing of different types of sensors such as semiconductor sensors and catalytic combustion sensors, and the test range is relatively wide. Compared with the existing technology, it can take into account the three processes experienced in the production process of MEMS gas sensors, and is relatively simple and reliable overall.

[0048] 6. Piezoelectric jet valves and pneumatic dispensing valves can meet the needs of spotting sensitive material slurries with different viscosities. They can be set and selected according to actual needs. Piezoelectric jet valves or pneumatic dispensing valves can achieve jetting or dipping to meet different usage needs and have a wide range of applications.

[0049] 7. The needle drop position can be checked through an optical microscope to ensure test accuracy.

[0050] 8. Laser cutting is adopted, the structure and principle are relatively simple, and cutting is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 Schematic diagram of a MEMS gas sensor wafer micromachining and testing system according to an embodiment of the present invention (with the scribing system hidden);

[0052] Figure 2 This is a front view of a MEMS gas sensor wafer micromachining and testing system according to an embodiment of the present invention;

[0053] Figure 3 A top view of a MEMS gas sensor wafer micromachining and testing system according to an embodiment of the present invention (with the dicing system hidden);

[0054] Figures 4-6 Schematic diagram of a probe card rack and a probe card according to an embodiment of the present invention;

[0055] Figure 7 is a three-axis schematic diagram of an embodiment of the present invention;

[0056] Figure 8 A schematic diagram of a system in an embodiment of the present invention;

[0057] Figure 9 This is a CAD example diagram of a sensor in a wafer according to an embodiment of the present invention;

[0058] Figure 10 for Figure 9 A partial enlarged view of middle A;

[0059] Figure 11 This is a schematic diagram of the system operation logic diagram in an embodiment of the present invention;

[0060] Figure 12 A partial schematic diagram of a Mapping diagram in an embodiment of the present invention;

[0061] Figure 13 for Figure 12 A partial enlarged view of B in the middle;

[0062] in,

[0063] Frame-1; frame base-11; support plate-12; rectangular notch-13; stand-14;

[0064] Operating platform-2;

[0065] Spotting system-3;

[0066] Test system-4; probe card rack-41; probe card-42; optical microscope-43; air outlet-411; air inlet-412; first vertical axis-431; swing rod-432; second vertical axis-433;

[0067] Dicing system-5;

[0068] Three-axis robotic arm-6; rotating mechanism-61; upper slide module-62; vertical slide module-63; lower slide module-64;

[0069] Vision system-7; camera-71; camera lifting drive mechanism-72. DETAILED DESCRIPTION

[0070] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0071] Example 1:

[0072] like Figure 1 、 8 As shown, a MEMS gas sensor wafer micromachining and testing system includes a frame 1, on which are provided an operating platform 2, a sample spotting system 3, a testing system 4, a dicing system 5, a sample spotting station, a testing station, a dicing station, a driving device, a visual system 7, and a control unit; the sample spotting system 3, the testing system 4, the dicing system 5, the driving device, and the visual system 7 are electrically connected to the control unit respectively.

[0073] The wafer to be micro-processed and tested is placed on the operating platform 2, and the driving device can drive the operating platform 2 to move to the sampling station, the testing station, and the scribing station respectively. The sampling system 3, the testing system 4, and the scribing system 5 can respectively perform sampling, detection, and scribing on the wafer below them, and the visual system 7 can identify the wafer. Specifically, the sampling station refers to the position of the operating platform 2 and the wafer when the sampling system 3 performs sampling on the wafer. In this embodiment, the sampling station is located below the sampling system 3. Similarly, the testing station refers to the position of the operating platform 2 and the wafer when the testing system 4 performs detection on the wafer. In this embodiment, the testing station is located below the testing system 4. The scribing station refers to the position of the operating platform 2 and the wafer when the scribing system 5 performs scribing on the wafer. In this embodiment, the scribing station is located below the scribing system 5.

[0074] In this embodiment, the main function of the rack 1 is to provide a mounting position for the remaining components. The rack 1 is not limited to a specific shape, as long as it can meet the requirements of installing and matching the components and realize the corresponding functions. Figure 6 As shown, the frame 1 includes a rectangular frame base 11, a rectangular support plate 12 is provided at the inner bottom of the frame base 11, a rectangular notch 13 is provided in the middle of the support plate 12, and an inverted U-shaped stand 14 is provided on the upper rear part of the frame base 11.

[0075] The driving device adopts a three-axis mechanical arm 6, such as Figure 1 、 2 As shown, the three-axis robotic arm 6 is arranged on the frame 1, and a rotating mechanism 61 is provided at the movable end of the three-axis robotic arm 6. The three-axis robotic arm 6 can drive the rotating mechanism 61 to move in the horizontal plane and in the vertical direction; the rotation axis of the rotating mechanism 61 is along the vertical direction, and the operating platform 2 is installed at the movable end of the rotating mechanism 61.

[0076] Specifically, such as Figure 7 As shown, the three-axis robot arm 6 includes a pair of lower slide modules 64 arranged on the support plate 12. The two slide modules 64 are parallel and located on the left and right sides of the rectangular notch 13 respectively. The sliding direction of the lower slide module 64 is along the front-back direction. An upper slide module 62 is arranged between the slides of the two slide modules 64. The sliding direction of the slide of the upper slide module 62 is along the left-right direction. It also includes a vertical slide module 63 arranged vertically. The slide of the vertical slide module 63 is fixedly connected to the slide of the upper slide module 62. The rotating mechanism 61 adopts a DD rotary motor. The DD rotary motor is installed at the top of the vertical slide module 63, and the operating platform 2 is installed at the movable end of the DD rotary motor. The DD rotary motor is used for wafer correction.

[0077] The upper slide module 62 , the vertical slide module 63 , and the lower slide module 64 are all provided with corresponding grating scales to ensure accuracy.

[0078] like Figure 3 As shown, in this embodiment, the operating platform 2 is a square plate-shaped structure, and a suction device is provided on the operating platform 2, through which the operating platform 2 can suction the wafer placed on the operating platform 2. Specifically, the suction device includes a plurality of air suction holes provided on the operating platform 2, and the air suction holes are evenly distributed in an array on the operating platform 2. It also includes an external vacuum pump, which is connected to the air suction holes through a pipeline. When the vacuum pump is working, it can suction the wafer placed on the operating platform 2 through the air suction holes.

[0079] The operating platform 2 is provided with a heating device, and the operating platform 2 can dry the wafers placed on the operating platform 2 through the heating device. Specifically, the heating device includes a heating wire installed inside the operating platform 2, which can heat the wafers on the operating platform 2 through the heating wire, thereby achieving wafer drying.

[0080] like Figures 1-3 As shown, the spotting system 3 includes a piezoelectric jet valve and / or a pneumatic dispensing valve arranged on the frame 1. The piezoelectric jet valve and the pneumatic dispensing valve are both existing technologies and can be purchased commercially. The piezoelectric jet valve and / or the pneumatic dispensing valve are vertically installed on the front side of the stand 14. Dispensing is loading the gas-sensitive material on the sensor. The piezoelectric jet valve adopts a spraying method and does not need to change the spotting height, while the pneumatic dispensing valve needs to cooperate with laser height measurement, such as using a laser rangefinder to measure the height, and adopts a dipping method. When spotting, the spotting height needs to be changed in real time according to the height of the spotting position.

[0081] like Figure 1 As shown, the test system 4 includes a probe card rack 41 mounted on the frame 1. A probe card 42 is mounted on the probe card rack 41. The probe card 42 is used for sensor testing. In this embodiment, the probe card rack 41 includes two upright posts positioned above the front of the frame base 11. The two posts are located on either side of the rectangular notch 13, with the probe card 42 mounted between the two posts. The probe card 42 is conventional and commercially available. The corresponding probe card can be selected based on the test chip. For semiconductor sensors, a four-probe setup is recommended, while a three-probe setup is also possible for testing catalytic combustion sensors.

[0082] like Figure 1 As shown, the test system 4 also includes an optical microscope 43 arranged on the rack 1 or the probe card rack 41, and a CCD camera is provided at the eyepiece of the optical microscope 43. The optical microscope 43 can move in the horizontal plane and along the vertical direction, and the optical microscope 43 can observe the wafer and the probe card 42.

[0083] Specifically, such as Figure 1 As shown, in this embodiment, a first vertical shaft 431 is vertically mounted on the top of the left probe card holder 41. A swing arm 432 is rotatably mounted on the first vertical shaft 431. The swing arm 432 is a strip-shaped plate-like structure. The swing arm 432 is rotatably connected to the first vertical shaft 431 via a bearing. A damper is provided between the swing arm 432 and the first vertical shaft 431 to ensure that the swing arm 432 can be fixed after swinging around the first vertical shaft 431 to a certain position. A second vertical shaft 433 is vertically mounted on the end of the swing arm 432. The optical microscope 43 is rotatably mounted on the second vertical shaft 433 via a bearing. A damper is provided between the optical microscope 43 and the second vertical shaft 433 to ensure that the optical microscope 43 can be fixed after swinging around the second vertical shaft 433 to a certain position. This allows the optical microscope 43 to observe the dispensing status of the wafer in the appropriate position and can also be used to correct the probe card position.

[0084] like Figure 4 、 5 As shown, the probe card holder 41 is provided with an air outlet 411 and an air intake 412. The air outlet 411 can release the test atmosphere or exhaust clean air, while the air intake 412 can absorb the test atmosphere. The wafer can be moved between the air outlet 411 and the air intake 412 along with the operating platform 2. The air outlet 411 and the air intake 412 are used for sensor sensitivity testing. During the test, the test atmosphere is released through the air outlet 411. After the test, the clean air is exhausted through the air outlet 411, and the air intake 412 absorbs the test atmosphere.

[0085] Specifically, such as Figure 4 、 5 As shown, the cross-sections of the air outlet 411 and the air intake 412 are both rectangular. The air outlet 411 is arranged at the top left position of the probe card holder 41 on the right side, and the air intake 412 is arranged at the top right position of the probe card holder 41 on the left side. The positions of the air outlet 411 and the air intake 412 are both higher than the operating platform 2.

[0086] like Figure 2 As shown, the air intake port 412 is connected to the aforementioned vacuum pump for air intake. Furthermore, the system also includes an air compressor, to which the air outlet 411 is connected for atmosphere purging. The air compressor is also used to provide pressure for dispensing glue. Connecting the air compressor to the dispensing system 3 provides pressure for dispensing glue.

[0087] The scribing system 5 includes a laser arranged on the frame 1, and the laser is specifically arranged on the front side of the stand 14. When the wafer moves to the bottom of the laser along with the operating platform 2, the laser can perform laser cutting on the wafer to realize the scribing operation.

[0088] like Figure 1As shown, the visual system 7 includes a camera 71 vertically slidably mounted on the frame 1. The camera 71 is used for positioning, template acquisition, glue point status detection, wafer observation, glue point correction, visual recognition, etc. Specifically, a camera lifting drive mechanism 72 is provided in the middle of the front side of the stand 14. The camera 71 is mounted on the movable end of the camera lifting drive mechanism 72. The camera lifting drive mechanism 72 is located between the spotting system 3 and the dicing system 5. Specifically, the camera lifting drive mechanism 72 can be implemented using a slide module, a cylinder, an electric cylinder, etc. In this embodiment, a vertically arranged slide module is used, and the camera 71 is mounted on the slide of the slide module.

[0089] The control unit adopts a programmable logic controller, namely PLC. PLC is an existing technology. The operator can use PLC to control the spotting system 3, the probe card 42, the dicing system 5, the rotating mechanism 61, the upper slide module 62, the vertical slide module 63, the lower slide module 64, the camera 71, and the camera lifting drive mechanism 72.

[0090] In practical applications, the MEMS gas sensor wafer micromachining and testing system of the present invention combines the three processes involved in MEMS gas sensor manufacturing, including spotting, testing, and dicing, to form a micromachining and testing system for MEMS gas sensors, significantly reducing firmware costs in mass production of sensors. The system can also identify whether a sample has been spotted through a visual system 7, allowing for resampling of some chips with poor quality spots to improve yield. The test results are used for selective packaging of sensors, and subsequent operations are not performed on sensors that exceed the required range, significantly reducing sensor production costs. The system takes into account the coating of gas-sensitive materials, testing, and dicing of MEMS gas sensor wafers, and has an overall low cost.

[0091] Under the action of the three-axis robotic arm 6 and the rotating mechanism 61, the wafer can move horizontally and vertically along with the operating platform 2, and can rotate around the vertical axis, thereby meeting the needs of wafer position adjustment, and the movement is flexible and reliable. The piezoelectric injection valve and the pneumatic dispensing valve can meet the needs of spotting sensitive material slurries of different viscosities. They can be set and selected according to actual needs and have a wide range of applications. In actual application, the probe card 42 and the chip's needle drop position can be calibrated using an optical microscope 43 and a CCD camera. The system records the relative position of the needle drop and drops the needle at the same position on other chips to ensure detection accuracy. In addition, the wafer dispensing status can be observed through the optical microscope 43 and the CCD camera. The air outlet 411 and the air intake 412 are used for sensor sensitivity testing. During the test, the test atmosphere is released from the air outlet 411. After the test, the clean air is discharged from the air outlet 411, and the test atmosphere is absorbed by the air intake 412. The overall structure of the air outlet 411 and the air intake 412 is simple and easy to use, which can conveniently and quickly test the sensitivity of the sensor.

[0092] Example 2:

[0093] The present invention also discloses a method for using the above-mentioned MEMS gas sensor wafer micromachining and testing system, such as Figure 11 As shown, the following steps are included:

[0094] Figure 11 The workbench height setting shown is to set the height of the operating platform 2;

[0095] S1. Wafer position correction

[0096] After the wafer is placed on the operating platform 2, the driving device drives the operating platform 2 to move the wafer, and the visual system 7 finds the characteristic points on the chip. The DD rotary motor drives the operating platform 2 to correct the chip array of the wafer to a horizontal and vertical position to perform wafer position correction;

[0097] S2. Forming a Mapping Graph

[0098] The system is based on CAD drawings, such as Figure 9 、 10 The state shown in the figure forms a Mapping diagram, that is, Figure 12 、 13 The state shown in FIG. 1 is that the Mapping diagram is an array of blocks of the size of a single chip, which are sorted. Each block in the Mapping stores the serial number, location information, and test results of the chip. The array is matched with the actual chip position in the visual system 7, and any chip can be selected in the system for observation, testing, material loading, and other operations. Figure 9 、 10As shown in the figure, the rectangular blank area that is not completely covered by the points in the CAD example is the mark position. The number and location of the mark positions can be set according to actual needs. There is a point in the rectangular blank area, which is the mark point. The mark point is different from other points in the CAD example. The CAD example is formed as shown in the figure. Figure 12 、 13 When the mapping diagram is shown, other points except the marked points will form a square of the size of a single chip, while the marked points in the rectangular blank area do not form a square. The rectangular blank area is a completely blank rectangle in the mapping diagram, that is, Figure 12 、 13 In the state shown, the rectangular blank area marked in the Mapping diagram can be used for system positioning to achieve point alignment.

[0099] Point selection allows you to select the desired operating point within the array diagram. You can add, delete, and mark point locations. The system also displays the locations of operated points, distinguishing them by color, which can be customized. The system also allows you to directly control the machine's movement to the desired observation point using the mouse, with the corresponding image displayed on the interface.

[0100] S3, spotting

[0101] The wafer moves along the operating platform 2 to the spotting station below the spotting system 3, and the spotting system 3 includes a piezoelectric injection valve and / or a pneumatic dispensing valve arranged on the frame 1;

[0102] Choose between spraying or dipping, two different methods to cover sensitive material slurries of different viscosities:

[0103] When performing injection spotting through a piezoelectric injection valve, set the spotting height, that is, the distance between the chip and the valve port of the piezoelectric injection valve, determine the spotting position, set the piezoelectric injection valve parameters, and correct the state and position of the glue dot;

[0104] When performing dispensing and sampling through a pneumatic dispensing valve, determine the dispensing position, set the dispensing height and pneumatic dispensing valve parameters, and correct the state and position of the glue dot; then perform dispensing.

[0105] During the dispensing process, after setting the relevant dispensing parameters and selecting the sample location, the sample can be dispensed. The parameters are then adjusted repeatedly until the desired dispensing state is achieved. An algorithm corrects any deviations between the desired sample location and the actual dispensing point, ensuring the dispensing point lands in the ideal location. Adjusting the dispensing state and position is known as dispensing point correction. Select the desired dispensing location and then proceed with batch loading.

[0106] The system can also capture images of selected chips or locations as templates, determining whether to dispense based on the desired location and similarity. Material loading and dispensing locations can be set directly across the entire wafer, or based on test mapping, to target unqualified locations or locations classified as having a specific level for refilling. The system can also capture images for recognition, determining whether to dispense based on the desired location and similarity. This allows for refilling of chips with poor quality dispensed material, improving yield.

[0107] After spotting, the temperature and heating time of the operating platform 2 are set to dry the wafer. Specifically, the wafer is dried by the heating wire inside the operating platform 2.

[0108] S4. Testing

[0109] The test system 4 includes a probe card rack 41 disposed on the rack 1, on which a probe card 42 is disposed; and an optical microscope 43 disposed on the rack 1 or the probe card rack 41, wherein a CCD camera is disposed at the eyepiece of the optical microscope 43. The optical microscope 43 is movable in a horizontal plane and in a vertical direction, and is capable of observing the wafer and the probe card 42.

[0110] S41. Proofreading

[0111] The wafer moves with the operating platform 2 to the test station under the test system 4. The optical microscope 43 is used to calibrate the probe card 42 and the probe position of the chip. The system records the relative position of the probe and then performs probe placement on the same position of other chips.

[0112] When testing a semiconductor sensor, execute step S42; when testing a catalytic combustion sensor, execute step S43;

[0113] S42, test the heating resistance, cold resistance, chip adjacent pin resistance and the corresponding current and voltage;

[0114] S43, testing the heating wire resistance and bridge bias voltage;

[0115] The applied voltage can be set to pulse application mode in addition to normal voltage.

[0116] The system can output test data and classify and mark the data according to a given range. The test results are in Mapping format, including all test data, and can be converted to other formats such as Excel and TXT. At the same time, the system can read Mapping format data and replenish materials at points with higher resistance.

[0117] The sensor's sensitivity can be tested through air outlet 411 and air inlet 412. This sensitivity test begins with calibration in clean air, followed by observation of sensor performance changes in the test atmosphere. During testing, the test atmosphere is released through air outlet 411. After the test is complete, clean air is expelled from air outlet 411, while air inlet 412 draws in the test atmosphere. The sensitivity of semiconductor sensors and catalytic combustion sensors is determined by the change in sensor performance in clean air and the test atmosphere.

[0118] S5. Dicing

[0119] The scribing system 5 includes a laser arranged on the frame 1;

[0120] Draw the motion lines in CAD, and the motion path is automatically generated after importing. The scribing is based on the CAD drawing. The wafer moves with the operating platform 2 to the scribing station under the laser. The laser point correction is performed through the visual system 7. The wafer moves linearly with the operating platform 2 according to the generated motion path, and the laser cuts the wafer.

[0121] Through the above method, the MEMS gas sensor wafer can be coated with gas-sensitive materials, tested, and cut. When the wafer position is corrected, the wafer can be accurately corrected to the predetermined position, thereby ensuring the accuracy of spotting, testing, and dicing. After the CAD drawing is input into the system, the system forms an array of blocks the size of a single chip and sorts them according to the requirements to form a mapping diagram. The array can be matched with the actual chip position through the visual system 7. Any chip can be selected in the system for observation, testing, and material loading, etc., which is relatively convenient to operate. The piezoelectric injection valve or pneumatic dispensing valve can be used to achieve injection spotting or dip spotting to meet different usage requirements and has a wide range of applications. The optical microscope 43 can be used to calibrate the needle drop position to ensure test accuracy. The system can realize the testing of different types of sensors such as semiconductor sensors and catalytic combustion sensors. The test range is wide. The laser cutting method is used, the structure and principle are relatively simple, and cutting is convenient. Compared with the existing technology, it can take into account the three processes experienced in the production process of MEMS gas sensors, and the overall process is relatively simple and reliable.

[0122] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A MEMS gas sensor wafer micromachining and testing system, characterized by: The machine comprises a frame on which an operating platform, a sample spotting system, a test system, a scribing system, a sample spotting station, a test station, a scribing station, a drive device, a visual system, and a control unit are arranged; the sample spotting system, the test system, the scribing system, the drive device, and the visual system are electrically connected to the control unit respectively; the drive device can drive the operating platform to move to the sample spotting station, the test station, and the scribing station respectively; A method using a MEMS gas sensor wafer micromachining and testing system, comprising: S1. Wafer position correction Correct the chip array on the wafer to a horizontal and vertical position; S2. Forming a Mapping Graph The system uses CAD drawings as its basis to form a mapping diagram. The mapping diagram is an array of blocks the size of a single chip, which are sorted. Each block in the mapping stores the chip's serial number, location information, and test results. The array is mapped to the actual chip position in the visual system, and any chip can be selected in the system for observation, testing, and material loading operations. S3, spotting The wafer moves with the operating platform to the spotting station, and the spotting system spots the wafer. Dry the wafer after spotting; S4. Testing The drive device drives the operating platform to move the wafer to the test station. When the test system tests the semiconductor sensor, it tests the heated resistance, cold resistance, chip adjacent pin resistance and the corresponding current and voltage. When the test system tests the catalytic combustion sensor, it tests the heating wire resistance and bridge bias voltage. S5. Dicing The drive device drives the operating platform to move the wafer to the dicing station, and the dicing system cuts the wafer.

2. The MEMS gas sensor wafer micromachining and testing system according to claim 1, characterized in that: The driving device adopts a three-axis robotic arm, the movable end of which is provided with a rotating mechanism, which can drive the rotating mechanism to move in the horizontal plane and in the vertical direction; The rotating axis of the rotating mechanism is along the vertical direction, and the operating platform is installed at the movable end of the rotating mechanism.

3. The MEMS gas sensor wafer micromachining and testing system according to claim 1, wherein: The test system includes a probe card rack arranged on a rack, wherein a probe card is arranged on the probe card rack; It also includes an optical microscope arranged on a rack or a probe card rack, a CCD camera is arranged at the eyepiece of the optical microscope, the optical microscope can move in the horizontal plane and along the vertical direction, and the optical microscope can observe the wafer and the probe card.

4. The MEMS gas sensor wafer micromachining and testing system according to claim 3, characterized in that: The probe card rack is provided with an air outlet and an air intake, and the wafer can be moved between the air outlet and the air intake along with the operating platform.

5. The MEMS gas sensor wafer micromachining and testing system according to claim 1, wherein: The vision system consists of a camera mounted on a vertical sliding frame.

6. The MEMS gas sensor wafer micromachining and testing system according to claim 1, wherein: In step S1, after the wafer is placed on the operating platform, the driving device drives the operating platform to move the wafer, finds the characteristic points on the chip through the visual system, and corrects the chip array of the wafer to a horizontal and vertical position through the operating platform to perform wafer position correction.

7. The MEMS gas sensor wafer micromachining and testing system according to claim 1, wherein: In step S3, the spotting system includes a piezoelectric jet valve and / or a pneumatic dispensing valve arranged on a frame; select jet spotting or dip spotting: when performing jet spotting through the piezoelectric jet valve, set the spotting height, that is, the distance between the chip and the valve port of the piezoelectric jet valve, determine the spotting position, set the piezoelectric jet valve parameters, and correct the state and position of the glue dot; when performing dip spotting through the pneumatic dispensing valve, determine the spotting position, set the spotting height and pneumatic dispensing valve parameters, and correct the state and position of the glue dot; then perform spotting.

8. The MEMS gas sensor wafer micromachining and testing system according to claim 1, wherein: In step S4, the test system includes a probe card rack mounted on a rack, the probe card being mounted on the probe card rack; and an optical microscope mounted on the rack or the probe card rack, the eyepiece of the optical microscope being provided with a CCD camera, the optical microscope being capable of moving in a horizontal plane and in a vertical direction, and being capable of observing the wafer and the probe card. First, the wafer is moved to the test station along with the operating platform. The probe card and chip's probe placement are first verified using an optical microscope. The system records the relative placement of the probes and repeats the same placement on other chips. After proofreading is completed, testing is carried out; the test results are in Mapping format, containing all the test data and can be converted into other formats; At the same time, the system can read Maping format data and replenish materials at points with higher resistance.

9. The MEMS gas sensor wafer micromachining and testing system according to claim 1, wherein: In step S5, the dicing system includes a laser set on a frame; the motion lines are drawn in CAD, and the motion path is automatically generated after importing. The dicing is based on the CAD drawing, and the wafer moves to the dicing station along with the operating platform. The laser point correction is performed through the visual system, and the wafer moves linearly along the operating platform according to the generated motion path, and the laser cuts the wafer.

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