MEMS gyroscope orthogonal coupling on-wafer automatic testing device and method

Abstract

The present invention provides an on-wafer automatic test device for orthogonal coupling of MEMS gyroscopes, comprising: a test module that meets wafer-level orthogonal coupling test requirements, is integrated on a low-parasitic parameter probe card, is connected to a gyroscope to be tested via a low-parasitic probe, and is used to perform orthogonal coupling testing on the gyroscope to be tested; an acquisition and configuration module that is connected to the test module and is used to configure parameters of the test module and collect drive signals and detection signals of the gyroscope to be tested; and a control module that is connected to the acquisition and configuration module and is used to calculate orthogonal coupling data of the gyroscope to be tested based on the drive signals and the detection signals. The present invention can accurately and batch-test gyroscope orthogonal coupling at the wafer level, eliminate chips with unqualified orthogonal coupling, and prevent unqualified chips from entering the next production link, thereby shortening the product iteration cycle, improving production efficiency, and reducing production costs.

Description

Technical Field

[0001] The present invention relates to the technical field of MEMS gyroscopes, and in particular to an on-wafer automatic testing device and method for orthogonal coupling of a MEMS gyroscope. Background Art

[0002] During the MEMS gyroscope manufacturing process, due to etching errors or mask alignment errors, the moving mass of the MEMS gyroscope may not be completely symmetrical. This can cause vibration displacement in the driving direction to couple to the detection direction, resulting in motion displacement in the detection direction even without angular velocity input. This coupling of motion signals from the driving direction to the detection direction due to manufacturing errors is called orthogonal coupling.

[0003] The size of orthogonal coupling directly reflects the process level of chip processing, and also directly affects the stability, linearity, temperature, vibration and other performance of the gyroscope. It is a very important parameter indicator of MEMS gyroscope.

[0004] Quadrature coupling is only detectable when the gyro drive loop is operating stably, and the change in quadrature coupling capacitance is extremely small, making it extremely difficult to accurately measure at the wafer level. Existing on-wafer testing technology for MEMS gyros can only accurately and batch-test parameters such as resistance, capacitance, frequency, and quality factor, but cannot apply gyro quadrature coupling testing to production.

[0005] Currently, orthogonal coupling testing can only be performed after the chip, circuit, and package are fully packaged, which greatly increases production costs.

[0006] Therefore, the present invention provides an on-wafer automatic testing device and method for orthogonal coupling of a MEMS gyroscope. Summary of the Invention

[0007] In order to solve the above problems of the prior art, the present invention provides a MEMS gyroscope orthogonal coupling on-wafer automatic testing device, the device comprising:

[0008] A test module that meets wafer-level orthogonal coupling test requirements, is integrated on a low-parasitic parameter probe card, and is connected to the gyroscope to be tested via a low-parasitic probe to perform an orthogonal coupling test on the gyroscope to be tested;

[0009] an acquisition and configuration module connected to the test module, configured to configure parameters of the test module and acquire the drive signal and detection signal of the gyroscope to be tested;

[0010] A control module is connected to the acquisition and configuration module and is used to calculate the orthogonal coupling data of the gyroscope to be tested according to the drive signal and the detection signal.

[0011] According to one embodiment of the present invention, the test module includes:

[0012] a closed-loop driving unit connected to the gyroscope to be tested, and configured to drive the gyroscope to be tested in a closed-loop manner so as to achieve stable amplitude resonance;

[0013] A detection unit is connected to the gyroscope to be tested and is used to detect and obtain the detection signal of the gyroscope to be tested.

[0014] According to one embodiment of the present invention, the closed-loop driving unit includes: a first capacitor-voltage conversion unit, a first analog-to-digital conversion unit, a first bandpass filtering unit, an automatic gain control unit, and a digital-to-analog conversion unit.

[0015] According to one embodiment of the present invention, the detection unit includes: a second capacitance-to-voltage conversion unit, a second analog-to-digital conversion unit, and a second band-pass filtering unit.

[0016] According to one embodiment of the present invention, the test module is packaged in a ceramic tube shell with high reliability and low parasitic characteristics, and the packaged test module is welded on the low parasitic parameter probe card with peripheral circuits required by the test module.

[0017] According to one embodiment of the present invention, the low-parasitic probe has high conductivity, high hardness, high wear resistance, non-magnetic and low-parasitic characteristics.

[0018] According to one embodiment of the present invention, the control module includes:

[0019] a parameter configuration unit, configured to adjust the circuit frequency and the balancing capacitance according to a preset algorithm to ensure that the gyroscope to be tested operates normally;

[0020] A signal processing unit is used to calculate and obtain the orthogonal coupling data of the gyroscope to be tested according to the driving signal and the detection signal.

[0021] According to one embodiment of the present invention, the device further comprises:

[0022] The probe station is provided with a plurality of gyro detection positions and the low-parasitic probes matched therewith, and supports continuous batch orthogonal coupling testing of a plurality of the gyros to be tested.

[0023] According to one embodiment of the present invention, the control module further comprises:

[0024] The probe station control unit is used to control the probe station to move to the next gyroscope to be tested after the test of the previous gyroscope to be tested is completed.

[0025] According to another aspect of the present invention, a method for automatically testing orthogonal coupling on-wafer MEMS gyroscopes is provided, wherein the method is performed by using the apparatus described in any one of the above items, and the method comprises the following steps:

[0026] Performing an orthogonal coupling test on the gyroscope to be tested using a test module that meets wafer-level orthogonal coupling test requirements, wherein the test module is integrated on a low-parasitic parameter probe card and connected to the gyroscope to be tested via a low-parasitic probe;

[0027] Performing parameter configuration on the test module through the acquisition and configuration module, and acquiring the driving signal and detection signal of the gyroscope to be tested;

[0028] The orthogonal coupling data of the gyroscope to be tested is obtained by calculation according to the driving signal and the detection signal by a control module.

[0029] The MEMS gyroscope orthogonal coupling on-wafer automatic testing device and method provided by the present invention can accurately and batch-test gyroscope orthogonal coupling at the wafer level, eliminate orthogonal coupling unqualified chips, and prevent unqualified chips from entering the next production link, shortening the product iteration cycle, improving production efficiency, and reducing production costs.

[0030] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0032] Figure 1 Shows a structural block diagram of an on-wafer automatic test device for orthogonal coupling of a MEMS gyroscope according to an embodiment of the present invention;

[0033] Figure 2 A schematic diagram showing the connection relationship between the gyroscope to be tested and the test module according to an embodiment of the present invention; and

[0034] Figure 3 A flow chart of an on-wafer automatic testing method for MEMS gyroscope orthogonal coupling according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions and advantages of the present invention more clear, embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

[0036] MEMS gyroscopes, characterized by their small size, light weight, low power consumption, mass production, and affordability, have been widely used in consumer electronics, automotive, and other fields. With their continuous performance improvements, MEMS gyroscopes have become the core of micro-inertial systems and a key component driving the miniaturization of navigation systems. They are also poised to gradually replace traditional gyroscopes. Orthogonal coupling is a key parameter of MEMS gyroscopes. With the widespread application of MEMS gyroscopes, on-wafer testing of gyroscope orthogonal coupling and the elimination of substandard chips are crucial for reducing production costs and improving efficiency.

[0037] In the prior art, CN103018651B proposes an on-wafer testing system and method for MEMS devices, which includes: small capacitance detection, resistance, resonant frequency and quality factor testing. However, it does not include orthogonal coupling parameter testing of gyroscopes.

[0038] In the prior art, CN1666952 proposes a dynamic test loading device for a MEMS wafer or device, but it is only a loading device for testing a MEMS device and does not involve an orthogonal coupling test method.

[0039] The existing paper, "Development of an On-Wafer Automatic Test System for MEMS Gyroscopes" (Digital Technology and Applications, 202004), provides a general introduction to the entire on-wafer test system, capable of testing various gyroscope parameters. This test parameter includes orthogonal coupling testing, but the method and implementation of this test are not clearly described.

[0040] Therefore, the present invention proposes an on-wafer automatic testing device and method for orthogonal coupling of MEMS gyroscopes, which can realize accurate, automatic and batch testing of orthogonal coupling of MEMS gyroscopes at the wafer level, avoid unqualified orthogonal coupling chips from entering the next link, improve production efficiency and reduce production costs.

[0041] Figure 1 The figure shows a structural block diagram of an on-wafer automatic test device for orthogonal coupling of a MEMS gyroscope according to an embodiment of the present invention.

[0042] like Figure 1 As shown, the MEMS gyroscope orthogonal coupling on-wafer automatic testing device 100 includes a testing module 101 , an acquisition and configuration module 102 , and a control module 103 .

[0043] The test module 101 meets the wafer-level orthogonal coupling test requirements, is integrated on a low-parasitic parameter probe card, and is connected to the gyroscope to be tested through a low-parasitic probe to perform an orthogonal coupling test on the gyroscope to be tested.

[0044] In one embodiment, the test module 101 is packaged in a ceramic tube package with high reliability and low parasitic characteristics. The packaged test module 101 is soldered on a low parasitic parameter probe card with peripheral circuits required by the test module 101 .

[0045] In one embodiment, the low-parasitic probe is a key component for connecting the gyroscope to be tested and the test module 101. The low-parasitic probe has high conductivity, high hardness, high wear resistance, non-magnetic properties, and low parasitic properties. Specifically, the low-parasitic probe is made of beryllium copper.

[0046] In one embodiment, test module 101 utilizes a dedicated MEMS gyroscope ASIC circuit, with a fourth-order micro-electromechanical sigma-delta digital closed-loop control for the drive loop. This supports gyroscope frequencies up to 30kHz, a maximum drive voltage of 8V, and noise levels of 50zF / sqrt(Hz). This system offers advantages such as a wide frequency range, low noise, high precision, and flexible parameter tuning, meeting wafer-level orthogonal coupling test requirements.

[0047] like Figure 1 As shown, the acquisition and configuration module 102 is connected to the test module 101 and is used to configure parameters of the test module 101 and acquire the driving signal and the detection signal of the gyroscope to be tested.

[0048] Specifically, the acquisition and configuration module 102 realizes the communication between the test module 101 and the control module 103. Its main functions include configuring the circuit register parameters of the test module 101, acquiring the drive signal D r and the detection signal S e .

[0049] In one embodiment, the acquisition and configuration module 102 uses a NI acquisition card.

[0050] like Figure 1 As shown, the control module 103 is connected to the acquisition and configuration module 102 and is used to calculate the orthogonal coupling data of the gyroscope to be tested based on the driving signal and the detection signal. Specifically, the control module 103 is implemented by the host computer software.

[0051] Specifically, the control module includes: a parameter configuration unit and a signal processing unit, wherein:

[0052] The parameter configuration unit is used to adjust the circuit frequency and the balancing capacitance according to a preset algorithm to ensure that the gyroscope to be tested works normally.

[0053] Due to manufacturing errors, the drive frequency and balance capacitance of each gyro under test vary. Therefore, after loading the test module's initial circuit configuration file, adjustments must be made to each gyro under test to ensure stable drive and proper testing. The parameter configuration unit automatically adjusts the circuit frequency and balance capacitance based on an algorithm to ensure proper operation of the gyro under test.

[0054] The signal processing unit is used for calculating and obtaining the orthogonal coupling data of the gyroscope to be tested according to the driving signal and the detection signal.

[0055] Specifically, after the gyro under test works normally, the signal processing unit will collect the driving signal D r and the detection signal S e Perform data processing and calculate the orthogonal coupling data of the gyroscope to be tested.

[0056] like Figure 1 As shown, the MEMS gyroscope orthogonal coupling on-wafer automatic test device 100 further includes a probe station, which has multiple gyroscope detection positions and matching low-parasitic probes, supporting continuous batch orthogonal coupling testing of multiple gyroscopes to be tested.

[0057] In one embodiment, the control module 103 further includes a probe station control unit configured to control the probe station to move to the next gyroscope to be tested after the test of the previous gyroscope is completed. Specifically, after the test of one gyroscope is completed, the control module 103 controls the automatic probe station to move to the next gyroscope to be tested for orthogonal coupling testing.

[0058] In summary, the present invention integrates the test module 101 into a low parasitic parameter probe card, and the low parasitic probe connects the MEMS gyroscope to be tested to the test module 101 on the low parasitic parameter probe card. The control module 103 automatically configures the test module 101 through the acquisition and configuration module 102, adjusts the parameters of the test module 101, and makes the drive loop of the MEMS gyroscope to be tested work stably, while detecting the detection signal and the drive signal. The acquisition and configuration module 102 transmits the detection signal and the drive signal of the gyroscope to be tested to the control module 103. The control module 103 processes the collected data and calculates the orthogonal coupling data of the gyroscope to be tested. The control module 103 also controls the motion of the probe station to realize automatic testing of the entire wafer.

[0059] Figure 2 A schematic diagram showing the connection relationship between a gyroscope to be tested and a test module according to an embodiment of the present invention is shown.

[0060] like Figure 2 The test module 101 includes a closed-loop drive unit and a detection unit, wherein:

[0061] The closed-loop driving unit is connected to the gyroscope to be tested and is used to drive the gyroscope to be tested for closed-loop control so that the gyroscope to be tested can achieve stable amplitude resonance.

[0062] Specifically, the closed-loop driving unit includes: a first capacitance-voltage conversion unit (C / V), a first analog-to-digital conversion unit (ADC), a first bandpass filter unit (BPF), an automatic gain control unit (AAC) and a digital-to-analog conversion unit (DAC).

[0063] The detection unit is connected to the gyroscope to be tested and is used to detect and obtain a detection signal from the gyroscope to be tested.

[0064] Specifically, the detection unit includes: a second capacitance-to-voltage conversion unit (C / V), a second analog-to-digital conversion unit (ADC), and a second band-pass filtering unit (BPF).

[0065] like Figure 2 As shown, the gyroscope to be tested is connected to the test module 101 via low parasitic probes (connection line 1 and connection line 2), and the test module 101 drives the gyroscope to be tested and performs closed-loop control to achieve stable amplitude resonance.

[0066] When the gyroscope to be tested is in steady resonance:

[0067] D r =A d ×sin(ω d t) (1)

[0068] Among them, D r is the driving signal of the gyroscope to be tested, A d is the amplitude, ω d is the resonant frequency.

[0069] When the gyroscope to be tested is in steady resonance, the amplitude A is measured. d and the resonant frequency ω d , the driving signal D of the gyroscope to be tested can be obtained through the above formula (1) r .

[0070] like Figure 2 As shown, in the detection link in the test module 101, the orthogonal coupling signal is detected after passing through the second capacitance-voltage conversion unit (C / V), the second analog-to-digital conversion unit (ADC) and the second bandpass filter unit (BPF).

[0071] S e =Q u ×A d ×sin(ω d t) (2)

[0072] Among them, S e is the detection signal of the gyroscope to be tested, Q uIt is the orthogonal coupling of the gyroscope to be measured.

[0073] From formula (1) and formula (2), we can get:

[0074]

[0075] According to the detection signal and the driving signal of the gyroscope to be tested, the orthogonal coupling data of the gyroscope to be tested can be obtained according to formula (3).

[0076] In summary, the present invention can realize accurate, automatic, and batch testing of orthogonal coupling wafer level of MEMS gyroscopes, avoid orthogonal coupling unqualified chips from entering the next link, improve production efficiency, and reduce production costs.

[0077] Figure 3 The flowchart of the on-wafer automatic testing method of MEMS gyroscope orthogonal coupling according to one embodiment of the present invention is shown. Figure 3 As shown, the on-wafer automatic test of MEMS gyroscope orthogonal coupling is performed by using the apparatus described in any one of the above items.

[0078] like Figure 3 In step S301, an orthogonal coupling test is performed on the gyroscope to be tested by a test module that meets the wafer-level orthogonal coupling test requirements, wherein the test module is integrated on a low parasitic parameter probe card and connected to the gyroscope to be tested through a low parasitic probe.

[0079] like Figure 3 In step S302, the test module is configured with parameters through the acquisition and configuration module, and the drive signal and detection signal of the gyroscope to be tested are acquired.

[0080] like Figure 3 In step S303, the control module calculates the orthogonal coupling data of the gyroscope to be tested according to the driving signal and the detection signal.

[0081] In summary, the MEMS gyroscope orthogonal coupling on-wafer automatic testing device and method provided by the present invention can perform accurate and batch testing of gyroscope orthogonal coupling at the wafer level, eliminate unqualified orthogonal coupling chips, and prevent unqualified chips from entering the next production link, shortening the product iteration cycle, improving production efficiency, and reducing production costs.

[0082] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should extend to equivalent substitutions of these features understood by those skilled in the relevant art. It should also be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting.

[0083] References in this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Therefore, appearances of the phrases "one embodiment" or "an embodiment" in various places throughout this specification do not necessarily refer to the same embodiment.

[0084] Although the embodiments disclosed herein are as described above, the contents described herein are merely embodiments for facilitating understanding of the present invention and are not intended to limit the present invention. Any person skilled in the art of the present invention may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed herein. However, the scope of patent protection of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. A MEMS gyroscope orthogonal coupling on-wafer automatic test device, characterized in that: The device comprises: A test module that meets wafer-level orthogonal coupling test requirements, is integrated on a low-parasitic probe card, and is connected to the gyroscope under test via a low-parasitic probe for performing orthogonal coupling testing on the gyroscope under test. The test module is encapsulated in a ceramic tube housing with high reliability and low parasitic characteristics, and the low-parasitic probe is made of beryllium copper. an acquisition and configuration module connected to the test module, configured to configure parameters of the test module and acquire the drive signal and detection signal of the gyroscope to be tested; a control module connected to the acquisition and configuration module, and configured to calculate and obtain the orthogonal coupling data of the gyroscope to be tested based on the drive signal and the detection signal; The test module includes: a closed-loop driving unit connected to the gyroscope to be tested, used to drive the gyroscope to be tested in a closed-loop control manner so that the gyroscope to be tested achieves stable amplitude resonance; a detection unit connected to the gyroscope to be tested, used to detect and obtain the detection signal of the gyroscope to be tested; The closed-loop drive unit includes: a first capacitance-voltage conversion unit, a first analog-to-digital conversion unit, a first band-pass filter unit, an automatic gain control unit, and a digital-to-analog conversion unit connected in sequence, wherein the input end of the first capacitance-voltage conversion unit is connected to the gyroscope to be tested via a connecting line 2, and the output end of the digital-to-analog conversion unit is connected to the gyroscope to be tested via a connecting line 1; The detection unit comprises: a second capacitance-voltage conversion unit, a second analog-to-digital conversion unit, and a second band-pass filtering unit connected in sequence, wherein the input end of the second capacitance-voltage conversion unit is connected to the gyroscope to be tested; When the gyroscope to be tested is in stable resonance, the driving signal is obtained by the following expression: D r =A d ×sin(ω d t) The orthogonal coupling data of the gyroscope to be tested is obtained by the following expression: Where: Q u is the orthogonal coupling of the gyroscope to be measured; S e is the detection signal of the gyroscope to be tested; D r A is the driving signal of the gyroscope to be tested; d is the amplitude; ω d is the resonant frequency; The device supports a gyro frequency of up to 30kHz, a driving voltage of up to 8V, and a noise of 50zF / sqrt(Hz).

2. The MEMS gyroscope orthogonal coupling on-wafer automatic test device according to claim 1, characterized in that: The packaged test module is welded on the low parasitic parameter probe card with the peripheral circuit required by the test module.

3. The MEMS gyroscope orthogonal coupling on-wafer automatic test device according to claim 1, characterized in that: The low-parasitic probe has high conductivity, high hardness, high wear resistance, non-magnetic and low parasitic characteristics.

4. The MEMS gyroscope orthogonal coupling on-wafer automatic test device according to claim 1, characterized in that: The control module includes: a parameter configuration unit, configured to adjust the circuit frequency and the balancing capacitance according to a preset algorithm to ensure that the gyroscope to be tested operates normally; A signal processing unit is used to calculate and obtain the orthogonal coupling data of the gyroscope to be tested according to the driving signal and the detection signal.

5. The MEMS gyroscope orthogonal coupling on-wafer automatic test device according to claim 1, characterized in that: The device further comprises: The probe station is provided with a plurality of gyro detection positions and the low-parasitic probes matched therewith, and supports continuous batch orthogonal coupling testing of a plurality of the gyros to be tested.

6. The MEMS gyroscope orthogonal coupling on-wafer automatic test device according to claim 5, characterized in that: The control module further comprises: The probe station control unit is used to control the probe station to move to the next gyroscope to be tested after the test of the previous gyroscope to be tested is completed.

7. A method for automatically testing orthogonal coupling on-wafer MEMS gyroscopes, characterized in that: The device according to any one of claims 1 to 6 is used to perform on-wafer automatic testing of MEMS gyroscope orthogonal coupling, the method comprising the following steps: Performing an orthogonal coupling test on the gyroscope to be tested using a test module that meets wafer-level orthogonal coupling test requirements, wherein the test module is integrated on a low-parasitic parameter probe card and connected to the gyroscope to be tested via a low-parasitic probe; Performing parameter configuration on the test module through the acquisition and configuration module, and acquiring the driving signal and detection signal of the gyroscope to be tested; The orthogonal coupling data of the gyroscope to be tested is obtained by calculation according to the driving signal and the detection signal by a control module.

Images