In-situ on-chip impact tensile strength online detection system and its manufacturing method and application

Abstract

The application discloses an in-situ on-chip impact tensile strength online detection system and a manufacturing method and application thereof, and belongs to the technical field of micro-electro-mechanical system processing, wherein the on-chip testing machine comprises a measured micro beam, an impacted mass block, a double-hammer-head structure, a first and second type probe loading structure, a lock catch structure, a lock tooth structure, a first to third type elastic suspension folded beam, an elastic energy storage beam, an elastic beam, a power bolt and a first to fifth fixed anchor point. The system combines the on-chip testing machine with a probe station to extract the fracture strength of the measured micro beam structure when the measured micro beam structure is subjected to impact tensile fracture. The impact tensile strength online detection of the measured micro beam is carried out through the system, and the system has the advantages of wide range and repeatability, and the method is simple, and large-scale precision instruments and thermal drive loading and unloading mechanisms are not needed.

Description

Technical Field

[0001] The present invention belongs to the field of micro-electromechanical system (MEMS) processing technology, and specifically discloses an in-situ on-chip impact tensile strength online detection system, a manufacturing method and an application thereof. Background Art

[0002] Microelectromechanical systems (MEMS) are a new technology based on microelectronics and micromachining. Since the 1990s, MEMS technology has rapidly developed due to its advantages such as light weight, small size, high sensitivity, ease of integration, and excellent performance. Various sensor devices manufactured based on this technology, such as pressure gauges, accelerometers, gyroscopes, microphones, and inertial measurement units (IMUs), are widely used in various aspects of the market, from consumer products to professional markets in extreme environments, and have huge potential for development.

[0003] Most sensor devices are subject to external shocks during their manufacturing, transportation, storage, and final use. Furthermore, because these devices often contain delicate movable structures (such as suspended membranes, cantilever beams, folded beams, and adhesive interfaces), they are extremely sensitive to external mechanical shocks. The inertial stress and contact stress generated by MEMS devices made of silicon-based brittle materials under external shock environments often become significant factors in causing device structural fracture and failure. Therefore, it is crucial to accurately predict the reliability of microstructures under external mechanical shocks and to extract parameters for the impact fracture strength of key structures in MEMS devices. Among these parameters, the impact tensile fracture strength of microbeams is one of the most important.

[0004] Currently, there are many common impact testing methods, including pendulum (or drop hammer) testing machines, Hopkinson bars, drop test platforms, vibration tables, light gas cannons, etc. These structures and methods are all aimed at sample structures at the millimeter scale and above. For samples at the micron scale and below, there are great difficulties in achieving their fixation, loading, positioning, self-alignment, and detection. Devices of this size are often tested by manufacturing the sample structure on a chip, slicing it, and packaging it before drop testing. However, these testing methods have major problems: the test process is one-time and cannot be repeated, the large-scale damage of the test sample cannot accurately analyze the impact damage behavior of the device structure, and it is impossible to directly test the impact strength of micro-nanostructured samples. Therefore, it is necessary to propose a detection system and method with a wide range and repeatability that can realize online detection of impact tensile strength. Summary of the Invention

[0005] In response to the above-mentioned problems, the present invention proposes a novel double-hammer, wide-range, repeatable in-situ on-chip impact tensile strength online detection system, its manufacturing method and application. This detection system utilizes a newly designed on-chip testing machine structure in combination with a probe station, which can realize in-situ, online detection and extraction of the dynamic impact tensile strength of MEMS device structures under complex external mechanical impact environments, and obtain the destruction form and law of micro-beam structure specimens at micro-nano scale, thereby achieving accurate reliability prediction and quality monitoring of MEMS device structures.

[0006] The present invention adopts the following technical solutions:

[0007] An in-situ on-chip impact tensile strength online testing system comprises: an on-chip testing machine and a probe station for applying an external load force to the on-chip testing machine; the on-chip testing machine comprises: a microbeam to be tested, a mass to be impacted, a double hammer head structure, first and second type probe loading structures, a locking structure, a locking tooth structure, first to third types of elastic suspension folding beams, an elastic energy storage beam, an elastic beam, a power bolt, and first to fifth fixed anchor points, all of which are symmetrical about a vertical central axis;

[0008] The vertical sides of the measured micro-beam are respectively connected to the first fixed anchor point and the impacted mass block, and the horizontal sides of the impacted mass block are connected to the two second fixed anchor points through two first-class elastic suspension folding beams;

[0009] The two conical hammer heads of the double hammer head structure are close to the impacted mass block, and a type of probe loading structure is located between the two conical hammer heads. The lateral sides of the double hammer head structure are connected to two third fixed anchor points through two elastic energy storage beams.

[0010] The locking tooth structure is connected to the side of the double hammer head structure away from the conical hammer head, and two rows of first-class serrations are distributed on both sides of the locking tooth structure;

[0011] The lock buckle structure includes two laterally symmetrical parts, with a space between the two parts to accommodate the entry and exit of the lock tooth structure. Two second-class serrations that cooperate with the first-class serrations are provided on the inner sides of the two parts close to the lock tooth structure. The outer sides of the two parts are connected to two fourth fixed anchor points via two second-class elastic suspension folding beams. The vertical sides of the two parts away from the lock tooth structure are connected to two fifth fixed anchor points via two elastic beams.

[0012] One end of the power bolt is located between the two parts of the locking structure, and the other end is provided with a second-type probe loading structure. The lateral sides of the power bolt are connected to two sixth fixed anchor points through two third-type elastic suspension folding beams.

[0013] Furthermore, an anti-collision block is provided on a side of the impacted mass block away from the measured microbeam, with a gap being left between the anti-collision block and the impacted mass block.

[0014] Further, the end of the two tapered hammer heads of the impact hammer structure is circular arc-shaped, and is in linear contact with the impacted mass.

[0015] Further, the one type and the two type probe loading structures are circular arc-shaped grooves.

[0016] Further, the one type saw teeth are triangular saw teeth, and the two type saw teeth are circular arc-shaped saw teeth, and the one type saw teeth are in linear contact with the two type saw teeth.

[0017] Further, each elastic energy storage beam is composed of two parallel single beams.

[0018] Further, the first to sixth fixed anchor points can be square, rectangular or circular in shape.

[0019] A manufacturing method of an in-situ on-chip impact tensile strength online detection system, comprising the following steps of manufacturing an on-chip testing machine:

[0020] Anchors, including the first to sixth fixed anchor points, are formed on the front surface of the silicon wafer through photolithography and anisotropic etching processes;

[0021] A shallow groove is prepared on the surface of the glass wafer through photolithography and wet etching processes, a metal electrode is prepared in the shallow groove by sputtering and a metal electrode is prepared by a stripping process to prevent the footing effect;

[0022] The obtained silicon wafer and glass wafer are bonded by a silicon-glass anodic bonding process, and the metal electrode on the glass is pressed into the anchor point area;

[0023] The back surface of the silicon wafer is thinned to a preset thickness by a wet etching process;

[0024] An Al metal layer is sputtered on the back surface of the silicon wafer as a hard mask;

[0025] A movable structure is released by photolithography and anisotropic etching processes, and the movable structure is each structure of the on-chip testing machine except for each anchor point and the anti-collision block.

[0026] Further, the silicon wafer is an N-type single crystal silicon wafer with a resistivity of 0.001-0.003 Ω·cm, and Ti, Pt and Au are sputtered in the shallow groove on the surface of the glass.

[0027] An application of an in-situ on-chip impact tensile strength online detection system in the impact tensile strength detection of a micro beam, comprising the following steps:

[0028] The one type probe loading structure is loaded with displacement by the probe of the probe station until the one type saw teeth of the locking tooth structure are engaged with the two type saw teeth of the locking structure;

[0029] The probe of the probe station applies a displacement load to the second-type probe loading structure, driving the power bolt to act on the locking structure to release the engagement between the first-type sawtooth and the second-type sawtooth, and releasing the double hammer head structure to impact the measured micro-beam and the impacted mass block;

[0030] Observe the impact of the micro-beam under test. If the micro-beam under test is not damaged, repeat the above steps to make the first type of serrations of the lock tooth structure engage with the second type of serrations of the lock structure in the order from near to far from the lock structure until the micro-beam under test is damaged.

[0031] The position of the corresponding type of sawtooth when the microbeam under test is destroyed is recorded, the loading deflection is calculated, and the impact tensile strength is obtained.

[0032] The beneficial effects achieved by the present invention are as follows:

[0033] 1) The online detection system of the present invention can perform impact tensile testing on micro-scale micro-beam specimens;

[0034] 2) The online detection system of the present invention can monitor the process quality of the micro-beam preparation process;

[0035] 3) The online detection system of the present invention can achieve synchronous release of the lock structure based on the local contact between the lock tooth structure and the lock structure;

[0036] 4) The method for online testing of in-situ on-chip impact tensile strength using the online testing system of the present invention is simple and does not require the use of large precision instruments and thermal drive loading and unloading mechanisms;

[0037] 5) The online detection system of the present invention is repeatable and can realize repeated impact testing of the micro-beam specimen under test;

[0038] 6) The online detection system of the present invention has a wide range, and the impact structure loading deflection can reach hundreds of microns, meeting various testing requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of the structure of the on-chip test machine in an embodiment of the present invention.

[0040] Description of reference numerals:

[0041] 1: microbeam under test;

[0042] 2: impacted mass block;

[0043] 3: A type of elastic suspended folding beam;

[0044] 4: Anti-collision block;

[0045] 5: Double hammer structure;

[0046] 6: elastic energy storage beam;

[0047] 7: A type of probe loading structure;

[0048] 8: Locking tooth structure;

[0049] 9: Type I sawtooth;

[0050] 10: Locking structure;

[0051] 11: Class II sawtooth;

[0052] 12: elastic beam;

[0053] 13: Class II elastic suspension folding beam;

[0054] 14: Power bolt;

[0055] 15: Type II probe loading structure;

[0056] 16: Three types of elastic suspension folding beams;

[0057] 17: first fixed anchor point;

[0058] 18: second fixed anchor point;

[0059] 19: third fixed anchor point;

[0060] 20: fourth fixed anchor point;

[0061] 21: fifth fixed anchor point;

[0062] 22: Sixth fixed anchor point.

[0063] Figure 2 It is a side view of the on-chip tester in the embodiment of the present invention.

[0064] Figures 3A-3F This is a manufacturing flow chart of the on-chip tester in an embodiment of the present invention.

[0065] Description of reference numerals:

[0066] 31: Silicon wafer;

[0067] 32: Metal electrode;

[0068] 33: glass piece;

[0069] 34: anchor point;

[0070] 35: hard mask;

[0071] 36: Movable structure. DETAILED DESCRIPTION

[0072] To further enhance the understanding of the aforementioned features and advantages of the present invention, the following embodiments are described in detail with reference to the accompanying drawings. Those skilled in the art will readily understand the structure, advantages, and efficacy of the present invention from the following embodiments. The present invention may also be implemented or applied in various other specific embodiments, and the details herein may be modified and altered based on different perspectives and applications without departing from the spirit and scope of the present invention.

[0073] This embodiment discloses an in-situ on-chip impact tensile strength online detection system, comprising: an on-chip tester and a probe station for applying an external load force to the on-chip tester. The on-chip tester structure is as follows Figure 1 and Figure 2 As shown, it includes: a micro-beam to be measured 1, an impacted mass block 2, a type-one elastic suspension folding beam 3, an anti-collision block 4, a double hammer structure 5, an elastic energy storage beam 6, a type-one probe loading structure 7, a locking tooth structure 8, a type-one sawtooth 9, a locking structure 10, a type-two sawtooth 11, an elastic beam 12, a type-two elastic suspension folding beam 13, a power bolt 14, a type-two probe loading structure 15, a type-three elastic suspension folding beam 16, and first to sixth fixed anchor points 17, 18, 19, 20, 21, and 22. The overall structure of the on-chip test machine is symmetrical about the central axis of the micro-beam to be measured 1. For the convenience of description, the direction of the central axis is called the vertical direction, and the perpendicular direction is called the horizontal direction. Figure 1 The orientation in the Figure 1 The two sides above and below the center are called the upper side and the lower side respectively.

[0074] The lower side of the measured microbeam 1 is connected to the first fixed anchor point 17, and the upper side is connected to the lower side of the impacted mass 2. The length, width, and thickness of the measured microbeam 1 are all on the micrometer scale. The lateral sides of the impacted mass 2 are connected to the inner ends of two first-class elastic suspension folded beams 3, and the outer ends of the two first-class elastic suspension folded beams 3 are connected to two second fixed anchor points 18. The anti-collision block 4 is located above the impacted mass 2, with a certain gap between them to prevent the measured microbeam 1 from breaking due to excessive impact energy.

[0075] The double hammer structure 5 has two conical hammers on its upper side, with arc-shaped ends close to the lower side of the mass block 2 being struck. When in contact, the two are in line contact. The measured microbeam 1 and the first step fixed anchor point 17 are located in the space between the two conical hammers. A type of probe loading structure 7 is located in the middle of the two conical hammers and is a circular arc groove, which facilitates the alignment of the loading force and the positioning of the loading position ( Figure 1The downward arrow in the middle indicates the direction of the loading force. The lateral sides of the double hammer structure 5 are connected to the inner ends of two elastic energy storage beams 6, and the outer ends of the two elastic energy storage beams 6 are connected to two third fixed anchor points 19. Each elastic energy storage beam 6 is composed of two parallel single beams.

[0076] The locking tooth structure 8 is connected to the lower side of the double hammer head structure 5 , and two rows of first-class saw teeth 9 , specifically triangular saw teeth, are distributed on both sides of the locking tooth structure 8 .

[0077] The locking structure 10 includes two symmetrical parts, with a space left between the two parts for accommodating the entry and exit of the locking tooth structure 8. Two second-class serrations 11, specifically arc-shaped serrations, are provided on the inner side of the two parts near the upper side. The two second-class serrations 11 cooperate with the two rows of first-class serrations 9 to form a line contact, and the arc-shaped serrations and the triangular serrations are in partial contact, which can reduce friction resistance so as to achieve the synchronous release of the locking structure 10. The lateral sides of the locking structure 10 are connected to the inner ends of the two second-class elastic suspension folding beams 13, and the outer ends of the two second-class elastic suspension folding beams 13 are connected to the two fourth fixed anchor points 20. The lower side of the locking structure 10 is connected to the upper ends of the two elastic beams 12, and the lower ends of the two elastic beams 12 are connected to the two fifth fixed anchor points 21.

[0078] The upper end of the dynamic bolt 14 is located between the two parts of the locking structure 10. By inserting it between the two parts of the locking structure 10 under the action of the loading force, the locking tooth structure 8 is released, thereby releasing the elastic energy storage beam 6. The second type probe loading structure 15 is set at the lower end of the dynamic bolt 14 and is an arc-shaped groove, which facilitates the alignment of the loading force and the positioning of the loading position ( Figure 1 The upward arrow in the middle indicates the direction of the loading force. The two lateral sides of the power bolt 14 are connected to the inner ends of the two third-class elastic suspension folding beams 16 , and the outer ends of the two third-class elastic suspension folding beams 16 are connected to the two sixth fixed anchor points 22 .

[0079] This embodiment also discloses a method for manufacturing an in-situ on-chip impact tensile strength online detection system, which mainly includes manufacturing an on-chip testing machine. The manufacturing process is as follows: Figures 3A-3F As shown, the process used is based on the standard bond deep etch release process, and the main steps include:

[0080] (1) Figure 3A As shown, the silicon wafer 31 is an N-type single crystal silicon wafer with a resistivity of 0.001 to 0.003 Ω·cm and a thickness of 390±10 μm. The silicon wafer 31 is anisotropically etched by photolithography and ASE to a depth of 4±0.5 μm to form steps, thereby forming anchor points 34 on the front side of the silicon wafer 31, including the first to sixth fixed anchor points.

[0081] (2) Figure 3BAs shown, the glass sheet 33 is made of pyrex7740 with a thickness of 500±10μm. Shallow grooves are prepared on the surface of the glass sheet 33 by photolithography and BHF wet etching process. The depth of the shallow grooves is PVD sputtering of metal Ti / Pt / Au and a lift-off process are used to prepare a metal electrode 32 that prevents the footing effect.

[0082] (3) Figure 3C As shown, the obtained silicon wafer 31 and glass wafer 33 are bonded by a silicon-glass anodic bonding process, and the metal electrode 32 on the glass wafer 33 is pressed into the anchor area to achieve intervention in the footing effect and detection of electrical signals.

[0083] (4) Figure 3D As shown, the back side of the silicon wafer 31 is thinned to a corresponding thickness of 60±5 μm by a wet etching process.

[0084] (5) Figure 3E As shown, a layer of Al metal film is PVD sputtered on the back of the silicon wafer 31 as a hard mask 35, the thickness of which is About to ensure the effect of deep etch release.

[0085] (6) Figure 3F As shown, the structure is released by photolithography and anisotropic etching processes to obtain a suspended movable structure 36 , which is the structure of the on-chip test machine except for the anchor points and anti-collision blocks.

[0086] This embodiment also discloses an application of an in-situ on-chip impact tensile strength online detection system for online detection of the impact tensile strength of a microbeam, the steps comprising:

[0087] a. Figure 1 As shown, the probe of the probe station is used to apply a corresponding displacement load to the first type of probe loading structure 7 until the first type of serrations 9 at the lower end of the locking tooth structure 8 is engaged with the second type of serrations 11 in the locking structure 10 .

[0088] b. Use the probe of the probe station to apply the corresponding displacement load to the type II probe loading structure 15, drive the power bolt 14 to act on the locking structure 10 to release the engagement between the type I serrations 9 and the type II serrations 11, and release the double hammer structure 5 to impact the microbeam sample 1 and the impacted mass block 2.

[0089] c. Observe the impact of the measured microbeam 1. If the measured microbeam 1 is not damaged, repeat the above steps so that the first type of serrations 9 of the locking tooth structure 8 are engaged with the second type of serrations 11 in the order from near to far with the locking structure 10 until the measured microbeam 1 is damaged.

[0090] d. Record the position of the first-class sawtooth 9 corresponding to the failure of the microbeam 1 in step c, and calculate the corresponding loading deflection to obtain the impact tensile strength. The loading deflection in the present invention can reach over 200 μm, which has a wide measurement range compared to the loading deflection of only tens of microns in traditional tensile testing machines. Repeat the above measurement process multiple times, applying different load thrusts at the arc-shaped loading port of the first-class probe loading structure 7, and the statistical impact tensile fracture strength value of the microbeam 1 under test during this impact tensile process can be obtained.

[0091] Furthermore, a mechanical model for impact simulation was constructed using COMSOL software. The loading deflection obtained when the microbeam 1 was damaged in step d was incorporated into the constructed mechanical model to obtain the impact acceleration and maximum stress peak value at the moment of impact between the double hammerhead structure 5, the microbeam 1, and the impact mass 2, i.e., the ultimate impact load strength value. Using COMSOL simulation software and related calculations, it was determined that the impact strength value of the microbeam 1 in this embodiment could reach 2.8 GPa.

[0092] The present invention adds a detection area containing the present system to a silicon wafer with functional devices, and manufactures the functional devices and the detection system through a standard SOG (silicon on glass) process. After the entire process is completed, the sample is subjected to impact strength testing by the present system to obtain the process-related mechanical characteristic parameters of the functional devices in real time and online.

[0093] The above embodiments are only used to describe the technical solutions of the present invention, but are not used to limit the present invention. Structural features and characteristics that are common knowledge are not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical concept of the present invention, in addition to maintaining the feature of combining the on-chip tester with the probe station for microelectronic process detection and analysis in the present invention, several modifications and improvements can be made to the structure of the on-chip tester. These should also be considered to be included in the scope of protection of the present invention, and the scope of protection of the present invention shall be based on the scope defined by the claims.

Claims

1. An in-situ on-chip impact tensile strength online detection system, characterized in that: include: An on-chip tester and a probe station for applying an external load force to the on-chip tester; The on-chip testing machine includes: a micro-beam to be measured, a mass to be impacted, a double hammer head structure, first and second type probe loading structures, a locking structure, a locking tooth structure, first to third types of elastic suspension folding beams, an elastic energy storage beam, an elastic beam, a power bolt and first to fifth fixed anchor points, all of which are symmetrical about a vertical central axis; The vertical sides of the measured micro-beam are respectively connected to the first fixed anchor point and the impacted mass block, and the horizontal sides of the impacted mass block are connected to the two second fixed anchor points through two first-class elastic suspension folding beams; The two conical hammer heads of the double hammer head structure are close to the impacted mass block, and a type of probe loading structure is located between the two conical hammer heads. The lateral sides of the double hammer head structure are connected to two third fixed anchor points through two elastic energy storage beams. The locking tooth structure is connected to the side of the double hammer head structure away from the conical hammer head, and two rows of first-class serrations are distributed on both sides of the locking tooth structure; The lock buckle structure includes two laterally symmetrical parts, with a space between the two parts to accommodate the entry and exit of the lock tooth structure. Two second-class serrations that cooperate with the first-class serrations are provided on the inner sides of the two parts close to the lock tooth structure. The outer sides of the two parts are connected to two fourth fixed anchor points via two second-class elastic suspension folding beams. The vertical sides of the two parts away from the lock tooth structure are connected to two fifth fixed anchor points via two elastic beams. One end of the power bolt is located between the two parts of the locking structure, and the other end is provided with a second-type probe loading structure. The lateral sides of the power bolt are connected to two sixth fixed anchor points through two third-type elastic suspension folding beams.

2. The in-situ on-chip impact tensile strength online detection system according to claim 1, characterized in that: An anti-collision block is provided on a side of the impacted mass block away from the measured micro-beam, with a gap being left between the anti-collision block and the impacted mass block.

3. The in-situ on-chip impact tensile strength online detection system according to claim 1, characterized in that: The ends of the two conical hammer heads of the impact hammer structure are arc-shaped and are in line contact with the impacted mass block.

4. The in-situ on-chip impact tensile strength online detection system according to claim 1, characterized in that: The loading structures of the first and second type probes are both arc-shaped grooves.

5. The in-situ on-chip impact tensile strength online detection system according to claim 1, characterized in that: The first type of saw teeth are triangular saw teeth, the second type of saw teeth are arc-shaped saw teeth, and there is line contact between the first type of saw teeth and the second type of saw teeth.

6. The in-situ on-chip impact tensile strength online detection system according to claim 1, characterized in that: Each elastic energy storage beam is composed of two parallel single beams.

7. The in-situ on-chip impact tensile strength online detection system according to claim 1, characterized in that: The structural shapes of the first to sixth fixed anchor points are square, rectangular or circular.

8. A method for manufacturing the in-situ on-chip impact tensile strength online detection system according to any one of claims 1 to 7, characterized in that: The steps for manufacturing a test-on-chip include: Etching on the front side of the silicon wafer by photolithography and anisotropic etching processes to form anchor points, including first to sixth fixed anchor points; Shallow grooves are prepared on the surface of the glass sheet through photolithography and wet etching processes, metal is sputtered in the shallow grooves, and a metal electrode with anti-footing effect is prepared through a lift-off process; The obtained silicon wafer and glass wafer are bonded by a silicon-glass anodic bonding process, and the metal electrodes on the glass are pressed into the anchor area; Thinning the back of the silicon wafer to a preset thickness through a wet etching process; Sputter a layer of Al metal on the back of the silicon wafer as a hard mask; The suspended movable structures are released through photolithography and anisotropic etching processes. The movable structures are various structures of the on-chip test machine except for the anchor points and anti-collision blocks.

9. The manufacturing method according to claim 8, wherein: The silicon wafer is an N-type single crystal silicon wafer with a resistivity of 0.001 to 0.003 Ω·cm; Ti, Pt and Au are sputtered in shallow grooves on the glass surface.

10. An application of the in-situ on-chip impact tensile strength online detection system according to any one of claims 1 to 7 in the impact tensile strength detection of micro-beams, characterized in that: The following steps are involved: Applying a displacement load to the first type of probe loading structure using a probe of a probe station until the first type of saw teeth of the locking structure engage with the second type of saw teeth of the locking structure; The probe of the probe station applies a displacement load to the second-type probe loading structure, driving the power bolt to act on the locking structure to release the engagement between the first-type sawtooth and the second-type sawtooth, and releasing the double hammer head structure to impact the measured micro-beam and the impacted mass block; Observe the impact of the micro-beam under test. If the micro-beam under test is not damaged, repeat the above steps to make the first type of serrations of the lock tooth structure engage with the second type of serrations of the lock structure in the order from near to far from the lock structure until the micro-beam under test is damaged. The position of the corresponding type of sawtooth when the microbeam under test is destroyed is recorded, the loading deflection is calculated, and the impact tensile strength is obtained.

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