MEMS probe, probe station and test method of probe station

Abstract

The invention provides an MEMS probe, a probe station and a test method of the probe station. The MEMS probe is used for testing an MEMS device chip, the probe comprises a probe head part and a pressure head part, and the length of the probe head part is larger than that of the pressure head part in the vertical direction; wherein the needle head part comprises a needle head, a needle head base and a needle head support, the needle head is connected with the needle head base, and the needle head base is connected with the first end of a cantilever beam of the needle head; the pressure head component comprises a pressure head, a pressure head base and a pressure head support, the pressure head is connected with the pressure head base, and the pressure head base is connected with the second end of the cantilever beam of the pressure head support; wherein the pressure head part is in contact with the cavity of the MEMS device and applies pressure to the cavity; the needle head part is in contact with a pin of the MEMS device to measure an electric signal of the MEMS device, the manufacturing cost of the needle head part, the cantilever beam and the pressure head part is far lower than the manufacturing cost of a special testing machine for the MEMS, and the testing cost of wafer testing is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a MEMS probe, a probe station and a method for testing the probe station. Background Art

[0002] Micro-Electro-Mechanical Systems (MEMS) is an integrated micro-device system consisting of MEMS devices, micro-actuators, signal processing and control circuits, etc. Among them, MEMS devices are processed and produced on wafers by semiconductor manufacturers.

[0003] Before packaging the MEMS device, it is necessary to perform wafer testing on it. At present, most of the wafer testing of MEMS devices is a test item under non-physical excitation, which can only reflect part of the performance of the MEMS device, and it is difficult to reflect the response of the MEMS device to physical excitation (for example, one or more of pressure, acceleration, magnetic field, etc.). If physical excitation is to be introduced in wafer testing, a MEMS dedicated tester is required to apply physical excitation to the MEMS device, and then the MEMS dedicated tester determines whether the MEMS device is defective based on the electrical signal of the MEMS device obtained. However, the price of MEMS dedicated testers is expensive, resulting in a high test cost for wafer testing. Therefore, how to reduce the test cost of wafer testing is a problem that urgently needs to be solved. Summary of the invention

[0004] The present invention provides a MEMS probe, a probe station and a method for testing the probe station, which can solve the problem that a MEMS dedicated tester is expensive, resulting in a high test cost for wafer testing.

[0005] According to a first aspect of the present invention, a MEMS probe is provided for testing a MEMS device chip, wherein the probe comprises a needle component and a pressure component, wherein the needle component is longer than the pressure component in a vertical direction; wherein:

[0006] The needle component comprises a needle, a needle base, and a needle support, wherein the needle is connected to the needle base, and the needle base is connected to the first end of the needle cantilever beam of the needle support;

[0007] The pressure head component includes a pressure head, a pressure head base, and a pressure head bracket, wherein the pressure head is connected to the pressure head base, and the pressure head base is connected to the first end of the pressure head cantilever beam of the pressure head bracket;

[0008] Wherein, the pressure head component contacts the cavity of the MEMS device and applies the pressure to the cavity;

[0009] The needle component contacts the pin of the MEMS device to measure the electrical signal of the MEMS device.

[0010] Optionally, the number of the needle components is the same as the number of pins in the MEMS device, and the arrangement of the needle components is the same as the arrangement of the pins in the MEMS device; the number of the pressure head components is the same as the number of cavities in the MEMS device, and the arrangement of the pressure head components is the same as the arrangement of the cavities in the MEMS device.

[0011] Optionally, the bottom of the needle component and the bottom of the pressure head component are located on the same horizontal plane, and the height difference between the top of the pressure head component and the top of the needle component is greater than or equal to 5 μm.

[0012] Optionally, the area of ​​the pressure head is 40000 μm 2 .

[0013] Optionally, the length of the pressure head cantilever beam is between 1400 μm and 2000 μm.

[0014] According to a second aspect of the present invention, there is provided a probe station, the probe station comprising the above-mentioned MEMS probe, probe card, and wafer carrier;

[0015] The probe card comprises a substrate and at least one MEMS probe, wherein the MEMS probe is electrically connected to the substrate through the bottom of the pressure head support beam of the pressure head support and the bottom of the needle support beam of the needle head support, and the probe card is used to apply pressure to the cavity of the MEMS device through the pressure head component at a target height, and to contact the pin of the MEMS device through the needle head of the probe to measure the electrical signal of the MEMS device; wherein the number and arrangement of the MEMS probes of the probe card are the same as the number and arrangement of the MEMS device chips on the MEMS device wafer;

[0016] The wafer carrier is located below the probe card, carries a test MEMS device wafer, and is used to adjust the height of the MEMS device wafer to a target height according to an initial height and a height increment.

[0017] Optionally, the probe station further includes a main control device, and the main control device is used to obtain the electrical signal and determine whether the MEMS device has a defect according to the electrical signal.

[0018] According to a third aspect of the present invention, a method for testing a probe station is provided, the method being applied to the main control device, the method comprising:

[0019] Using the wafer carrier to adjust the height of the MEMS device wafer so that the probes of the probe card contact the pins of the MEMS device to perform device connectivity testing;

[0020] An initial electrical signal group of the MEMS device is obtained by testing the contact between the needle and the pin of the MEMS device, and the height at this time is the initial height of the wafer carrier;

[0021] Raising the wafer carrier to a target height, using the probe card to apply pressure to the cavity of the MEMS device through the pressure head at the target height and contacting the pin of the MEMS device through the needle head to measure and obtain a zero-position electrical signal group of a dynamic test of the MEMS device;

[0022] Taking the target height of the wafer carrier as the starting point, changing the height increment of the wafer carrier to obtain a plurality of test heights, applying pressure to the MEMS device cavity by using the indenter of the probe card, and obtaining a test electrical signal group corresponding to the test height by contacting the needle with the MEMS device pin;

[0023] Whether the MEMS device has defects is determined according to the test electrical signal group and the zero-position electrical signal group.

[0024] Optionally, the zero-position electrical signal group and the test electrical signal group both include a first voltage and a second voltage, and determining whether the MEMS device has a defect according to the test electrical signal group and the zero-position electrical signal group includes:

[0025] determining a first voltage difference between a first voltage and a second voltage of the test voltage group;

[0026] Determining whether a first voltage difference of the test electrical signal group is greater than a first difference threshold;

[0027] When the first voltage difference is greater than the first difference threshold, the two largest differences are selected from the first voltage differences of several test electrical signal groups to determine whether the nonlinearity is satisfied. If not, the cavity of the MEMS device is offset.

[0028] Optionally, when the first voltage difference is less than or equal to the first difference threshold, it is determined whether the second voltage difference between the single electrical signal of the test electrical signal group and the single electrical signal corresponding to the zero-position electrical signal group meets the voltage threshold design rule. If not, the resistance position of the MEMS device is abnormal.

[0029] The present invention provides a MEMS probe for testing a MEMS device chip, characterized in that the probe comprises a needle part and a pressure part, the length of the needle part is greater than the pressure part in the vertical direction; wherein: the needle part comprises a needle, a needle base, and a needle support, the needle is connected to the needle base, and the needle base is connected to the first end of the cantilever beam of the needle; the pressure part comprises a pressure head, a pressure head base, and a pressure head support, the pressure head is connected to the pressure head base, and the pressure head base is connected to the second end of the cantilever beam of the pressure head support; wherein the pressure head part contacts the cavity of the MEMS device and applies pressure to the cavity; the needle head part contacts the pin of the MEMS device to measure the electrical signal of the MEMS device. The MEMS probe provided by the present invention can perform static testing on the MEMS device through the needle when the pressure head is not working, and can also apply physical excitation to the cavity of the MEMS device with the help of the pressure head part, and contact the pin of the MEMS device through the needle head part to measure the electrical signal of the MEMS device, so as to realize static testing and dynamic testing in one probe station, and dynamic testing does not need to separate additional equipment for testing, thus saving testing costs. Furthermore, since the manufacturing cost of the MEMS probe is much lower than the manufacturing cost of a MEMS dedicated tester, that is, the price of the MEMS probe provided by the present invention is much lower than that of a MEMS dedicated tester, the testing cost of wafer testing is reduced, and the problem of using expensive MEMS dedicated testers for wafer testing, which leads to high testing costs for wafer testing, is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 is a structural schematic diagram of a MEMS probe provided by an embodiment of the present invention;

[0032] Figure 2 is a schematic diagram of the contact between the cavity and the pressure head of the MEMS device provided by an embodiment of the present invention;

[0033] Figure 3 is a schematic diagram of the structure of a probe station provided by an embodiment of the present invention;

[0034] Figure 4 is a schematic diagram of the structure of a main control device provided by an embodiment of the present invention;

[0035] Figure 5 The present invention is a flow chart of a method for testing a probe station provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0038] The technical solution of the present invention is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0039] Figure 1 FIG. 1 is a schematic diagram of a structure of a MEMS probe provided by an embodiment of the present invention, which is used to test a MEMS device chip. Figure 1 As shown, the probe comprises a needle component 1 and a pressure component 2, and the length of the needle component 1 is greater than that of the pressure component 2 in the vertical direction; wherein:

[0040] The needle component 1 includes a needle 11, a needle base 12, and a needle support 13. The needle 11 is connected to the needle base 12, and the needle base 12 is connected to the first end of the cantilever beam 131 of the needle support 13;

[0041] The pressure head component 2 includes a pressure head 21, a pressure head base 22, and a pressure head bracket 23. The pressure head 21 is connected to the pressure head base 22. The second ends of the cantilever beams 231 of the pressure head base 22 and the pressure head bracket 23 are connected. The pressure head component 2 contacts the cavity of the MEMS device and applies pressure to the cavity. The needle component 1 contacts the pin of the MEMS device to measure the electrical signal of the MEMS device.

[0042] In the embodiment of the present invention, the number of needle parts 1 is the same as the number of pins in the MEMS device, and the arrangement of the needle parts 1 is the same as the arrangement of the pins in the MEMS device; the number of pressure head parts 2 is the same as the number of cavities in the MEMS device, and the arrangement of the pressure head parts 2 is the same as the arrangement of the cavities in the MEMS device. As an example, please refer to Figure 2 A MEMS device, the number of cavities 42 on the MEMS device is 1, the number of pins 41 is 5, and the corresponding MMES probe includes 1 pressure head component 2 and 5 needle components 1, wherein the relative position and arrangement of the pressure head component 2 and the needle component 1 correspond to the MEMS device, so that the same MEMS probe can be used to perform static testing and dynamic testing on the MEMS device at the same time, when the pressure head 21 does not contact the cavity 42 of the MEMS device, the MEMS device is statically tested through the needle 11, and when the pressure head 21 contacts the cavity 42 of the MEMS device and applies pressure to the cavity 42, the needle 11 tests the electrical signal of the pin 41 of the MEMS device, thereby realizing dynamic testing of the MEMS device, and the static test and dynamic test of the MEMS device can be completed in the same test machine, and there is no need to complete the static test and dynamic test on different test machines respectively, thereby reducing the MEMS device wafer testing cost.

[0043] The needle component 1 and the pressure component 2 are arranged to correspond to the relative positions of the pin 41 and the cavity 42 of the MEMS device. The needle support 13 includes a needle cantilever beam 131 and a needle support beam 132. The first end of the needle cantilever beam 131 is connected to the needle base 12, and the other end of the needle cantilever beam 131 is connected to the top of the needle support beam 132. The bottom of the needle support beam 232 is used to be electrically connected to the substrate. The pressure support 23 includes a pressure cantilever beam 231 and a pressure support beam 232. The first end of the pressure cantilever beam 231 is connected to the pressure base 22, and the other end of the pressure cantilever beam 231 is connected to the top of the pressure support beam 232. The bottom of the pressure support beam 232 is used to be electrically connected to the substrate. The pressure support beam 232 and the needle support beam 132 have the same height.

[0044] As one embodiment, the length of the pressure head cantilever beam 231 is between 1400μm and 2000μm, and the elastic deformation generated by the pressure head cantilever beam 231 changes linearly. Based on the material mechanical properties of the pressure head cantilever beam 231 itself, the pressure head cantilever beam 231 can provide a linearly increasing pressure for the pressure head 21. The length of the pressure head cantilever beam 231 can be flexibly set according to the selected material and the required mechanical properties. Preferably, the material of the pressure head cantilever beam 231 can be BeCu or NiCo. The length of the needle cantilever beam 131 can be the same as the length of the pressure head cantilever beam 231, or it can be different from the length of the pressure head cantilever beam 231, as long as the contact between the needle 11 and the MEMS device chip can be achieved. Those skilled in the art can select appropriate lengths of the pressure head cantilever beam 231 and the needle cantilever beam 131, and there is no limitation here.

[0045] As an example, when the material of the indenter cantilever beam 231 is BeCu, the length of the indenter cantilever beam 231 is 1600μm, the width is 40μm, and the thickness is 90μm, the indenter cantilever beam 231 can produce a height change of 50μm, which can provide a compressive stress of 0-1.1gf for the indenter. If the indenter 21 acts on the cavity of the MEMS device chip, it can generate 0~30.5kPa to the cavity; as another example, when the material of the indenter cantilever beam 231 is NiCo, the length of the indenter cantilever beam 231 is 1400μm, the width is 40μm, and the thickness is 90μm, the indenter cantilever beam 231 can produce a height change of 50μm, which can provide a compressive stress of 0-3.1gf for the indenter 21. If the indenter 21 acts on the cavity of the MEMS device chip, it can generate 0~86.0kPa to the cavity.

[0046] In some embodiments, the length of the needle component 1 is greater than that of the pressure component 2 in the vertical direction, the bottom of the needle component 1 and the bottom of the pressure component 2 are located on the same horizontal plane, and the height difference between the top of the pressure component and the top of the needle component is greater than or equal to 5μm. Since there is a height difference between the pressure head 21 and the needle 11, when the needle 11 in the MEMS probe contacts the pin of the MEMS device, the pressure head 21 does not contact the cavity of the MEMS device, and the MEMS device can be statically tested by the needle 11. When the pressure head 21 contacts the cavity of the MEMS device and applies pressure to the cavity, the needle 11 still contacts the pin of the MEMS device, and the electrical signal of the pin of the MEMS device can be tested, thereby realizing dynamic testing of the MEMS device. The static test and dynamic test of the MEMS device can be completed in the same test machine, reducing the cost of MEMS device wafer testing.

[0047] In some embodiments, the area of ​​the indenter 21 is 40000 μm 2 Since the tip area of ​​the MEMS probe in the prior art is about 5 μm2 , it is impossible to apply pressure to the cavity surface, otherwise the cavity will be crushed or slip. Area is 40000μm 2 The pressure generated by the pressure head 21 on the cavity of the MEMS device is much smaller than the pressure generated by the MEMS probe in the prior art, thereby avoiding the situation where the cavity of the MEMS device is crushed or the MEMS device slips due to excessive pressure on the cavity of the MEMS device.

[0048] The MEMS device in this embodiment may include Figure 2 The five pins 41, the cavity 42 and the four resistors 43 form a Wheatstone bridge. The resistor 43 is integrated in the cavity 42. When the cavity 42 is deformed by pressure, the stress directions of the four resistors 43 are different, causing the resistance value to change. The resistance value change will change the bridge balance of the Wheatstone bridge, thereby causing the change of the electrical signal output by the MEMS device.

[0049] For example, the MEMS device may be a pressure sensor. The pressure sensor may include Figure 2 The five pins (41), the cavity 42 and the four resistors (43) shown form a Wheatstone bridge.

[0050] As an implementation method, the manufacturing method of the MEMS probe in this embodiment is as follows:

[0051] Providing a first substrate, depositing a layer of patterned photoresist on the front side of the first substrate, using the patterned photoresist as a barrier layer to form cantilever beam grooves of a pressure head component and a needle head component through an etching process, and removing the patterned photoresist;

[0052] A layer of patterned photoresist is deposited on the back side of the first substrate, and the support beam grooves of the pressure head component 2 and the needle component 1 are formed by an etching process using the patterned photoresist as a barrier layer, the support beam groove of the pressure head component 2 is connected with the cantilever beam groove of the pressure head component 2 to form a pressure head support groove, and the support beam groove of the needle component 1 is connected with the cantilever beam groove of the needle component 1 to form a needle support groove, and the patterned photoresist is removed;

[0053] A sacrificial layer is formed in the groove of the indenter support and the groove of the needle support, and a metal material is deposited on the front of the first substrate to fill the groove of the indenter support and the groove of the needle support to form the indenter support 23 and the needle support 13, wherein the support beam material and the cantilever beam material are both metal materials, and the metal material can be BeCu, NiCo, which is not limited here;

[0054] A patterned photoresist with a needle base 12 and an indenter base pattern is formed on the front side of the first substrate, a first Ti / Cu layer is deposited, an indenter base 22 is formed at a first end of the indenter cantilever beam, and a first portion of the needle base 12 is formed at a first end of the needle cantilever beam;

[0055] A patterned photoresist with a needle base pattern is formed on the front side of the first substrate, and a second Ti / Cu layer is deposited on the first part of the needle base 12 to form the needle base 12, wherein the thickness of the needle base 12 is greater than or equal to the thickness of the pressure head base 22 (5 μm); solder is deposited on the pressure head base 22 and the needle base 12, and the solder may be Sn;

[0056] The back side of the first substrate is etched until the sacrificial layer is exposed to form a cavity, so that the pressure head cantilever beam and the needle cantilever beam are suspended and movable.

[0057] A second substrate is provided, and the indenter 21 and the needle 11 are prepared on the surface of the second substrate. First, a layer of SiN is deposited on the surface of the wafer, and then a photolithography process and an etching process are performed to form a larger indenter groove in the preset indenter area of ​​the second substrate, and a smaller needle groove in the preset needle area; KOH is used to wet-etch the indenter groove and the needle groove to form a bowl-shaped pattern in the preset indenter area of ​​the second substrate, that is, the pattern of the indenter 21; a quadrangular pyramid with a smaller needle area is formed in the preset needle area, that is, the pattern of the probe; metal Ni / Ni-W is deposited in the indenter pattern and the probe pattern to form an indenter with a bowl-shaped structure and a needle 11 with a quadrangular pyramid structure.

[0058] The first substrate having one side formed with the indenter base 22 and the needle base 12 is bonded to the second substrate having one side formed with the indenter 21 and the needle 11. Specifically, the indenter base solder is bonded to the indenter 21, and the needle base solder is bonded to the needle 11. Finally, the second substrate is removed by wet etching with a hydrofluoric acid solution to form a MEMS probe.

[0059] The MEMS probe provided by the present invention can perform static testing on the MEMS device through the needle when the pressure head is not working, and can also apply physical excitation to the cavity of the MEMS device with the help of the pressure head component, and measure the electrical signal of the MEMS device through the contact between the needle head component and the pin of the MEMS device, thereby completing static testing and dynamic testing in one probe station. The dynamic test does not require separate additional equipment for testing, saving testing costs. Furthermore, since the manufacturing cost of the MEMS probe is much lower than the manufacturing cost of the MEMS dedicated test machine, that is, the price of the MEMS probe provided by the present invention is much lower than the price of the MEMS dedicated test machine, the test cost of the wafer test is reduced, and the problem of using expensive MEMS dedicated test machines for wafer testing, resulting in high test costs for wafer testing, is solved.

[0060] Please refer to Figure 3The embodiment of the present invention further provides a probe station 3, which includes a probe card 31 and a wafer carrier 5; the probe card 31 includes a substrate 311 and at least one MEMS probe 312, the MEMS probe 312 is electrically connected to the substrate 311 through the bottom of the pressure head support beam 232 of the pressure head bracket 23 and the bottom of the needle support beam 132 of the needle head 11 bracket 13, the probe card 31 is used to apply pressure to the cavity 42 of the MEMS device through the pressure head component 2 at a target height, and contact the pin 41 of the MEMS device through the needle head 11 of the probe to measure the electrical signal of the MEMS device; wherein the number and arrangement of the MEMS probes 312 of the probe card 31 are the same as the number and arrangement of the MEMS device chips on the MEMS device wafer 5; the wafer carrier 6 is located below the probe card 31, carries the test MEMS device wafer 5, and is used to adjust the height of the MEMS device wafer 5 to the target height according to the initial height and the height increment.

[0061] Among them, the initial height can be understood as the height of the wafer carrier 6 when the probe and the pin 41 are in contact, that is, the height of the wafer carrier 6 when the needle 11 and the pin 41 are in contact. The height increment can be understood as the height of the wafer carrier 6 each time it rises on the basis of the initial height. The target height can be understood as the height of the wafer carrier 6 when the cavity of the MEMS device wafer 5 contacts the pressure head 21 in the probe card 31. Wafer testing generally includes wafer static testing and wafer dynamic testing. Wafer static testing generally refers to testing under non-physical excitation. Wafer dynamic testing generally refers to testing under physical excitation (for example, pressure). As an example, since the flatness of the wafer carrier 6 is 2μm, and the contact accuracy of the wafer carrier 6 in the direction perpendicular to the MEMS device wafer is 2μm, when the needle 11 contacts the pin of the MEMS device, there is still a height difference of 4μm between the pressure head 21 and the MEMS device cavity 42. In this embodiment, the height difference between the pressure head 21 and the needle 11 is set to 5μm, which can ensure that when the probe contacts the MEMS pin in static testing, the pressure head will not generate pressure on the cavity, so as to distinguish between static testing and dynamic testing. When all needles 11 are in contact with the pins 41 of the MEMS device, the wafer carrier 6 is not raised from the initial height according to the height increment, and the pressure head 12 does not contact the cavity 42, that is, the pressure head 21 does not generate pressure on the cavity 42. The MEMS device can be statically tested by the needle 11. When the wafer carrier 6 rises to the target height, the cavity of the MEMS device wafer 5 contacts the pressure head 21 in the probe card 31, and the pressure head cantilever beam 231 generates elastic deformation to provide pressure for the pressure head 21, thereby realizing dynamic testing of the MEMS device, thereby distinguishing between static testing of the wafer and dynamic testing of the wafer.

[0062] In a specific embodiment of the present invention, the probe station 3 is specifically used to add the initial height and the height increment to obtain the target height. The probe station 3 adjusts the initial height of the MEMS device to the target height so that the height of the cavity 42 of the MEMS device reaches the target height.

[0063] In the embodiment of the present invention, the candidate height of the probe can be determined by performing an open circuit / short circuit test on the MEMS device, and then a static resistance test is performed on the MEMS device; when the static resistance is within the preset resistance range, it means that the pressure head 21 is not in contact with the cavity 42, and the candidate height of the probe is the initial height of the wafer carrier 6. The candidate height can be understood as the height of the wafer carrier 6 determined when the open circuit / short circuit test is performed on the MEMS device.

[0064] In an embodiment of the present invention, the height of the MEMS device wafer 5 can be adjusted using the wafer carrier plate 6 so that the probe of the probe card contacts the pin 41 of the MEMS device to perform a device connectivity test and contacts the pin 41 of the MEMS device through the needle 11 to test the electrical signal of the MEMS device; when the electrical signal of the MEMS device is tested by contacting the pin 1 of the MEMS device through the needle 11, it is determined that the connection between the probe and the pin 41 is successful, and the static test result of the MEMS device is determined to be a passed test, thereby achieving a wafer static test, and the height is determined as the initial height. After determining the initial height, the height of the MEMS device wafer 5 is adjusted to the target height according to the initial height and the height increment using the wafer carrier 6; a probe card is used to apply pressure provided by the cantilever beam to the cavity 42 of the MEMS device through the pressure head 21 at the target height, and the probe contacts the pin 41 of the MEMS device through the needle 11 to measure the electrical signal of the MEMS device, and the rising height of the wafer carrier 6 is increased on the basis of the target height, the pressure head 21 applies pressure provided by the cantilever beam to the cavity 42 of the MEMS device, and the probe contacts the pin 41 of the MEMS device through the needle 11 to measure the electrical signal of the MEMS device; a series of electrical signals of the dynamic test are obtained, and whether the MEMS device has defects is determined based on the electrical signals to complete the dynamic test of the MEMS device.

[0065] In a specific embodiment of the present invention, the probe station 3 also includes Figure 4 The main control device 7 shown is used to obtain an electrical signal and determine whether the MEMS device has defects based on the electrical signal.

[0066] The main control device 7 may be a computer or a server. The main control device 7 may be a server. Figure 4 , a main control device 7 is provided, comprising:

[0067] processor 71; and

[0068] A memory 72, used to store executable instructions of the processor;

[0069] The processor 71 is configured to execute the above-mentioned method by executing the executable instructions.

[0070] The processor 71 can communicate with the memory 72 via a bus 73 .

[0071] Among them, the processor of the main control device 7 is used to provide computing and control capabilities. The memory of the main control device 7 includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a program and a database. The internal memory provides an environment for the operation of the operating system and the program in the non-volatile storage medium. The database of the main control device 7 is used to store data such as initial height, height increment, target height and electrical signals of MEMS devices. When the program is executed by the processor, the following test method of the probe station is implemented.

[0072] Specifically, the probe station 3 changes the height of the wafer carrier 6 to the target height according to the initial height and the height increment, thereby changing the distance between the pressure head 21, the needle 11 and the cavity 42, the pin 41, and the electrical signal of the MEMS device changes. The electrical signal of the MEMS device is measured by contacting the needle component 1 with the pin 41 of the MEMS device; the main control device 7 obtains the electrical signal and determines whether the MEMS device has defects based on the electrical signal.

[0073] In an embodiment of the present invention, the electrical signal can be understood as a voltage signal output by a MEMS device. The electrical signal can include an initial electrical signal group, a zero-position electrical signal group, and a test electrical signal group. The initial electrical signal group can be understood as a plurality of electrical signals of the MEMS device obtained by a needle contact test with the pins of the MEMS device when the height of the MEMS device wafer is adjusted by using a wafer carrier so that the probe of the probe card contacts the pins of the MEMS device for device connectivity test. The zero-position electrical signal group can be understood as a plurality of electrical signals of a dynamic test of the MEMS device obtained by applying pressure to the cavity of the MEMS device through a pressure head at a target height using a probe card and contacting the pins of the MEMS device through a needle. The test electrical signal group can be understood as a plurality of electrical signals corresponding to the test height obtained by applying pressure to the cavity of the MEMS device using a pressure head of the probe card and contacting the pins of the MEMS device through a needle when taking the target height of the wafer carrier as the starting point and changing the height increment of the wafer carrier multiple times. In one embodiment of the present invention, the initial electrical signal group, the zero-position electrical signal group, and the test electrical signal group all include a first voltage and a second voltage. The first voltage and the second voltage. The first voltage can be understood as the output voltage of the two resistors 43 in the first direction of the MEMS device measured by contacting the pin 41 of the MEMS device with the needle 11 of the probe card at different MEMS device wafer heights. The second voltage can be understood as the output voltage of the two resistors 43 in the second direction of the MEMS device measured by contacting the pin 41 of the MEMS device with the needle 11 of the probe card at different MEMS device wafer heights. The first direction is perpendicular to the second direction. Figure 2 For example, the resistors in the first direction are two resistors 43 in the vertical direction. The resistors in the second direction are two resistors 43 in the horizontal direction. In other embodiments, the resistors in the first direction may be two resistors 43 in the horizontal direction, and the resistors in the second direction may be two resistors 43 in the vertical direction.

[0074] For example, the initial height of the wafer carrier 6 is H1, the initial voltage is V0, the height increment is ΔOD, and the target height H2=H1+ΔOD; the probe station 3 adjusts the initial height H1 of the wafer carrier 6 to the target height H2, so that the cantilever beam produces elastic deformation and provides pressure for the pressure head 21. Specifically, the wafer carrier 6 moves upward, and when the height increment of the wafer carrier 6 is ΔOD, the pressure head 21 contacts the cavity 42 of the MEMS device, and the resistance of the MEMS device is subjected to pressure, resulting in a change in resistance, so that the electrical signal measured by the pin connected to the needle 11 changes, and the difference between the first voltage and the second voltage is V1 at this time, V1-V0>1mV; wherein, 1mV is the voltage measurement accuracy of the test machine, and since the voltage difference has changed, it can be known that the pressure head acts on the cavity surface. The voltage measurement accuracy of different test machines is different, and the voltage difference here is only used as an example, and is subject to the voltage measurement accuracy of the actual test machine, which is not limited here. The height increment at this time is recorded as OD1, V1 is the new zero position voltage, and the rising height increment of the wafer carrier plate 6 is increased on the basis of the target height. The pressure head 21 applies the pressure provided by the cantilever beam to the cavity 42 of the MEMS device and contacts the pin 41 of the MEMS device through the needle 11 to measure the electrical signal of the MEMS device; a series of electrical signals of the dynamic test are obtained, and whether the MEMS device has defects is determined based on the electrical signals to complete the dynamic test of the MEMS device.

[0075] If the cavity 42 of the MEMS device is offset, then during the above-mentioned dynamic test, the voltage difference between the first voltage and the second voltage is greater than the first difference threshold value V'. The first difference threshold value V' can be understood as the output voltage corresponding to the maximum test range of the deformation of the MEMS sensor cavity. The first difference threshold value V' can be 0.86mV. The test ranges of different MEMS devices are different, and the corresponding first difference threshold values ​​are also different, which are not limited here. The test range can be understood as the pressure range that the MEMS device can withstand. Therefore, in a specific embodiment of the present invention, the main control device 7 is specifically used to determine the first voltage difference between the first voltage and the second voltage; when the first voltage difference is greater than the first difference threshold value V', it is determined that the MEMS device has a cavity 42 offset defect, so as to detect the cavity 42 offset defect of the MEMS device that can only be detected in the packaging stage during the wafer testing stage, thereby reducing the packaging cost.

[0076] For example, when the height of the cavity 42 is H21, the first voltage is V11 and the second voltage is V21. The main control device 7 determines a first voltage difference ΔV1=V11-V21 between the first voltage and the second voltage. ΔV1<V', which determines that when the height of the cavity 42 is H21, the cavity 42 of the MEMS device is not offset.

[0077] When the height of the cavity 42 is H22, the first voltage is V12, and the second voltage is V22. The main control device 7 determines that the first voltage and the second voltage have a first voltage difference ΔV2=V12-V22; wherein ΔV1<V'<ΔV2, the main control device 7 can determine that when the height of the cavity 42 is H22, the cavity 42 of the MEMS device is offset, and determines that the MEMS device has a cavity 42 offset defect.

[0078] If the resistor 43 of the MEMS device is separated from the cavity 42, the resistor is not affected by the cavity pressure stress and changes its resistance value. There may be a situation where the first voltage difference is less than or equal to the first difference threshold, thereby causing missed detection. Therefore, the first voltage Va and the second voltage Vb measured by the probe at different test heights are respectively calculated to obtain ΔVa and ΔVb with the first voltage Va' and the second voltage Vb' obtained at the target height test, and it is determined whether the corresponding voltage threshold design rule is met. When it is determined that the corresponding voltage threshold design rule is met, it is indicated that the MEMS device does not have the resistor 43 separation defect. The design rule can be understood as the technical document corresponding to the MEMS device, which may include one or more of the chip specifications, functions, performance parameters, pin definitions, working principles and precautions of the MEMS device. The working principle may include that the voltage difference between the pin output voltage at different test heights and the pin output voltage at the target height is less than or equal to the preset difference threshold; the voltage threshold design rule can be understood as the voltage difference between the output voltage obtained by measuring the pin at the test height and the output voltage obtained by measuring the pin at the target height in the design rule is less than or equal to the preset difference threshold. In a specific embodiment of the present invention, the voltage difference between a single electrical signal of the test electrical signal group and a single electrical signal corresponding to the zero-position electrical signal group is a second voltage difference; specifically, the second voltage difference may include: the voltage difference between the first voltage Va measured by the probe and the first voltage Va' obtained by the target height test, and the voltage difference between the second voltage Vb measured by the probe and the second voltage Vb' obtained by the target height test. The preset difference threshold may include a first voltage threshold and a second voltage threshold. The first voltage threshold may be understood as the critical value of the voltage difference between the first voltage Va measured by the probe and the first voltage Va' obtained by the target height test. The second voltage threshold may be understood as the critical value of the voltage difference between the second voltage Vb measured by the probe and the second voltage Vb' obtained by the target height test. The main control device 7 may also be specifically used to determine that the MEMS device has a resistor 43 separation defect when the second voltage difference is greater than the first voltage threshold and / or the second voltage difference is greater than the second voltage threshold, so as to detect the resistor 43 separation defect of the MEMS device that can only be detected in the packaging stage during the wafer testing stage, thereby reducing the packaging cost.

[0079] For example, the main control device 7 can also be specifically used to: obtain a first voltage Va and a second voltage Vb by measuring at a test height through a probe, obtain a first voltage Va' and a second voltage Vb' by testing at a target height, the first voltage threshold is ΔVa', and the second voltage threshold is ΔVb'. ΔVa=Va-Va', ΔVb=Vb-Vb'. If ΔVa>ΔVa' and / or ΔVb>ΔVb', it is determined that the MEMS device has a resistor 43 separation defect.

[0080] In a specific embodiment of the present invention, the main control device 7 can also be specifically used to determine when ΔVa>ΔVa'. Figure 2 The resistor 43 in the first direction of the MEMS device shown is separated; the main control device 7 can also be specifically used to determine when ΔVb>ΔVb'. Figure 2 In the MEMS device shown, the resistors 43 in the second direction are separated.

[0081] The probe station 3 provided in the embodiment of the present invention can apply physical excitation (pressure of the cantilever beam) to the cavity 42 of the MEMS device with the help of the pressure head component 2, and then use the needle head component 1 to contact the pin 41 of the MEMS device to measure the electrical signal of the MEMS device, wherein the manufacturing cost of the needle head component 1 (needle 11, needle head base 13, needle head support 13), the cantilever beam 15 and the pressure head component 2 (pressure head 12, pressure head base 14, pressure head support 23) is much lower than the manufacturing cost of the MEMS dedicated test machine, that is, the price of the MEMS probe 312 provided by the present invention is much lower than that of the MEMS dedicated test machine, which reduces the test cost of wafer testing and solves the problem of using expensive MEMS dedicated test machines for wafer testing, resulting in high test cost of wafer testing.

[0082] The embodiment of the present invention further provides a testing method, which is applied to the main control device 7 . Figure 5 FIG. 1 is a flow chart of a testing method using the above-mentioned probe station provided by an embodiment of the present invention. Figure 5 As shown, the method specifically includes the following steps:

[0083] Step 101 : Using a wafer carrier, adjust the height of the MEMS device wafer so that the probes of the probe card contact the pins of the MEMS device to perform a device connectivity test.

[0084] Step 102 , obtaining an initial electrical signal group of the MEMS device through a contact test between a needle and a pin of the MEMS device, where the height is the initial height of the wafer carrier.

[0085] Step 103, raising the wafer carrier to a target height; using a probe card to apply pressure to the cavity of the MEMS device through a pressure head at the target height and contacting the pins of the MEMS device through the needle to measure a zero-position electrical signal group of a dynamic test of the MEMS device.

[0086] Step 104, starting from the target height of the wafer carrier, repeatedly changing the height increment of the wafer carrier to obtain several test heights, using the pressure head of the probe card to apply pressure to the MEMS device cavity and obtaining a test electrical signal group corresponding to the test height through the contact test between the needle and the MEMS device pin.

[0087] Step 105 , determining whether the MEMS device has defects based on the test electrical signal group and the zero-position electrical signal group.

[0088] In one embodiment of the present invention, the initial electrical signal group, the zero-position electrical signal group, and the test electrical signal group all include a first voltage and a second voltage.

[0089] The first voltage can be understood as the output voltage of two resistors in the first direction of the MEMS device measured by the probe card through the contact between the needle and the pin of the MEMS device when the height of the MEMS device wafer is the initial height, the target height and the test height. The second voltage can be understood as the output voltage of two resistors in the second direction of the MEMS device measured by the probe card through the contact between the needle and the pin of the MEMS device when the height of the MEMS device wafer is the initial height, the target height and the test height.

[0090] Specifically, determining whether the MEMS device has defects according to the test electrical signal in step 105 may include: determining the first voltage difference between the first voltage and the second voltage of the test voltage group; when the first voltage difference is greater than the first difference threshold, selecting the two largest differences among the voltage differences of several test electrical signal groups to determine whether the nonlinearity is satisfied. If not, the MEMS device has a cavity offset defect. When the first voltage difference is less than or equal to the first difference threshold, there may be two situations: the MEMS device does not have a cavity offset defect; or the resistance of the MEMS device is separated from the cavity, so that the cavity will not change its resistance under the influence of pressure, so that the voltage difference remains unchanged. Therefore, it is necessary to determine whether the second voltage difference between a single electrical signal of the test electrical signal group and a single electrical signal corresponding to the zero-position electrical signal group meets the voltage threshold design rule. If not, the resistance position of the MEMS device is abnormal.

[0091] Specifically, the second voltage difference may include the voltage difference between the first voltage of the test electrical signal group and the first voltage of the zero-position electrical signal group, and the voltage difference between the second voltage of the test electrical signal group and the second voltage of the zero-position electrical signal group. It is necessary to determine whether the voltage difference between the first voltage of the test electrical signal group and the first voltage of the zero-position electrical signal group, and the voltage difference between the second voltage of the test electrical signal group and the second voltage of the zero-position electrical signal group meet the voltage threshold design rule of the MEMS device. If the voltage threshold design rule is met, the MEMS device does not have defects. If the voltage threshold design rule is not met, the MEMS device has a defect of separation of the resistor 43 and the cavity 42. To determine whether the voltage difference between the first voltage of the test electrical signal group and the first voltage of the zero-position electrical signal group, and the voltage difference between the second voltage of the test electrical signal group and the second voltage of the zero-position electrical signal group meet the voltage threshold design rule of the MEMS device, please refer to the previous description, which will not be repeated here. The testing method of the present invention solves the problem of detecting the cavity 42 offset defect of the MEMS device that can only be detected in the packaging stage during the wafer testing stage, thereby reducing the packaging cost.

[0092] Among them, the first difference threshold V' can be understood as the output voltage corresponding to the maximum test range of the MEMS sensor cavity deformation. The first difference threshold V' can be 0.86mV. Different MEMS devices have different test ranges and corresponding first difference thresholds, which are not limited here.

[0093] In some embodiments, step 101 may specifically include: using the wafer carrier plate 6 to adjust the height of the MEMS device wafer 5 so that the probe of the probe card 31 contacts the pin 41 of the MEMS device to perform a device connectivity test; at this time, the probe of the probe card 31 just contacts the pin 41 of the MEMS device to obtain a static reference resistance value of the MEMS device. Specifically, the static reference resistance can be obtained by a volt-ampere test.

[0094] In the embodiment of the present invention, when the pressure head 21 is not working, the MEMS device is statically tested through the needle 11, and the cavity 42 of the MEMS device can also be physically stimulated by the pressure head component 2, and the electrical signal of the MEMS device is measured by contacting the pin 41 of the MEMS device through the needle component 1, thereby completing static testing and dynamic testing in one probe station 3. The dynamic test does not require separate additional equipment for testing, saving testing costs. Furthermore, since the manufacturing cost of the MEMS probe 312 is much lower than the manufacturing cost of the MEMS dedicated test machine, that is, the price of the MEMS probe 312 provided by the present invention is much lower than the price of the MEMS dedicated test machine, the test cost of the wafer test is reduced, and the problem of using expensive MEMS dedicated test machines for wafer testing, resulting in high test costs for wafer testing, is solved.

[0095] An embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the above-mentioned method is implemented.

[0096] Those of ordinary skill in the art can understand that the implementation of all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. 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 replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A MEMS probe for testing a MEMS device chip, characterized in that: The probe comprises a needle component and a pressure component, and the length of the needle component is greater than that of the pressure component in the vertical direction; wherein: The needle component comprises a needle, a needle base, and a needle support, wherein the needle is connected to the needle base, and the needle base is connected to the first end of the needle cantilever beam of the needle support; The pressure head component includes a pressure head, a pressure head base, and a pressure head bracket, wherein the pressure head is connected to the pressure head base, and the pressure head base is connected to the first end of the pressure head cantilever beam of the pressure head bracket; Wherein, the pressure head component contacts the cavity of the MEMS device and applies the pressure to the cavity; The needle component contacts the pin of the MEMS device to measure the electrical signal of the MEMS device.

2. The MEMS probe according to claim 1, characterized in that: The number of the needle parts is the same as the number of pins in the MEMS device, and the arrangement of the needle parts is the same as the arrangement of the pins in the MEMS device; the number of the pressure head parts is the same as the number of cavities in the MEMS device, and the arrangement of the pressure head parts is the same as the arrangement of the cavities in the MEMS device.

3. The MEMS probe according to claim 2, characterized in that: The bottom of the needle component and the bottom of the pressure head component are located on the same horizontal plane, and the height difference between the top of the pressure head component and the top of the needle component is greater than or equal to 5 μm.

4. The MEMS probe according to claim 2, characterized in that: The area of ​​the indenter is 40000 μm 2 .

5. The MEMS probe according to claim 1, characterized in that: The length of the pressure head cantilever beam is between 1400 μm and 2000 μm.

6. A probe station, characterized in that: The probe station comprises the MEMS probe, probe card, and wafer carrier according to any one of claims 1 to 5; The probe card comprises a substrate and at least one MEMS probe, wherein the MEMS probe is electrically connected to the substrate through the bottom of the pressure head support beam of the pressure head support and the bottom of the needle support beam of the needle head support, and the probe card is used to apply pressure to the cavity of the MEMS device through the pressure head component at a target height, and to contact the pin of the MEMS device through the needle head of the probe to measure the electrical signal of the MEMS device; wherein the number and arrangement of the MEMS probes of the probe card are the same as the number and arrangement of the MEMS device chips on the MEMS device wafer; The wafer carrier is located below the probe card, carries a test MEMS device wafer, and is used to adjust the height of the MEMS device wafer to a target height according to an initial height and a height increment.

7. The probe station according to claim 6, characterized in that: The probe station further includes a main control device, which is used to obtain the electrical signal and determine whether the MEMS device has a defect according to the electrical signal.

8. A testing method using the probe station according to any one of claims 6-7, wherein the method is applied to the main control device, characterized in that: The method comprises: Using the wafer carrier to adjust the height of the MEMS device wafer so that the probes of the probe card contact the pins of the MEMS device to perform device connectivity testing; An initial electrical signal group of the MEMS device is obtained by testing the contact between the needle and the pin of the MEMS device, and the height at this time is the initial height of the wafer carrier; Raising the wafer carrier to a target height, using the probe card to apply pressure to the cavity of the MEMS device through the pressure head at the target height and contacting the pin of the MEMS device through the needle head to measure and obtain a zero-position electrical signal group of a dynamic test of the MEMS device; Taking the target height of the wafer carrier as the starting point, changing the height increment of the wafer carrier to obtain a plurality of test heights, applying pressure to the MEMS device cavity by using the indenter of the probe card, and obtaining a test electrical signal group corresponding to the test height by contacting the needle with the MEMS device pin; Whether the MEMS device has defects is determined according to the test electrical signal group and the zero-position electrical signal group.

9. The method according to claim 8, characterized in that The zero-position electrical signal group and the test electrical signal group both include a first voltage and a second voltage, and determining whether the MEMS device has a defect according to the test electrical signal group and the zero-position electrical signal group includes: determining a first voltage difference between a first voltage and a second voltage of the test voltage group; Determining whether a first voltage difference of the test electrical signal group is greater than a first difference threshold; When the first voltage difference is greater than the first difference threshold, the two largest differences are selected from the first voltage differences of several test electrical signal groups to determine whether the nonlinearity is satisfied. If not, the cavity of the MEMS device is offset.

10. The method according to claim 9, characterized in that The method further comprises: When the first voltage difference is less than or equal to the first difference threshold, it is determined whether the second voltage difference between the single electrical signal of the test electrical signal group and the single electrical signal corresponding to the zero-position electrical signal group meets the voltage threshold design rule. If not, the resistance position of the MEMS device is abnormal.

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