A six-axis force sensor and a manufacturing method thereof

Abstract

The present invention discloses a six-axis force sensor and a manufacturing method thereof, relating to the field of semiconductor technology, to solve the problems that the six-axis force sensor has a large size, limited application fields, and is not conducive to precisely and conveniently performing intelligent control on the object to be measured. The six-axis force sensor includes: a semiconductor substrate and a semiconductor structure layer formed on the semiconductor substrate. The semiconductor substrate is a hollowed-out substrate, and the pattern of the semiconductor structure layer is a six-axis force sensor pattern, and the six-axis force sensor pattern corresponds to the structure of the six-axis force sensor. A six-axis force sensor and a manufacturing method thereof disclosed by the present invention are used for measuring the force condition of the object to be measured.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular, to a six-axis force sensor and a manufacturing method thereof. Background Art

[0002] As a sensor with complete six-axis force and torque in space, the six-axis force sensor plays a crucial role in the process of industrial automation and intelligence. It can simultaneously measure three force components along the coordinate axes and three torque components around the coordinate axes, and identify its environment based on six sets of separated information. It is mainly used for force and force position control, such as welding, grinding, assembly, trajectory tracking, etc.

[0003] At the present stage, the six-axis force sensor is mainly applied in the field of robots. Its minimum size is in the millimeter range, which not only limits its application fields, but also is not conducive to improving the accuracy and convenience of intelligent control of the measured object according to its force condition. Summary of the Invention

[0004] The purpose of the present invention is to provide a six-axis force sensor and a manufacturing method thereof, so as to expand the application fields of the six-axis force sensor and improve the accuracy and convenience of intelligent control of the measured object according to its force condition.

[0005] In a first aspect, the present invention provides a six-axis force sensor, including:

[0006] A semiconductor substrate and a semiconductor structure layer formed on the semiconductor substrate. The semiconductor substrate is a hollowed substrate, and the pattern of the semiconductor structure layer is a six-axis force sensor pattern, and the six-axis force sensor pattern corresponds to the structure of the six-axis force sensor.

[0007] Compared with the prior art, the six-axis force sensor provided by the present invention includes a semiconductor substrate and a semiconductor structure layer formed on the semiconductor substrate. Among them, the semiconductor substrate is a hollowed substrate, and the pattern of the semiconductor structure layer is a six-axis force sensor pattern, and the six-axis force sensor pattern corresponds to the structure of the six-axis force sensor. Due to the sensitivity of the semiconductor structure, the six-axis force sensor can more sensitively detect the force condition of the measured object, which is beneficial to improving the accuracy of detecting the force condition of the measured object, and thus can improve the accuracy and convenience of intelligent control of the measured object according to its force condition.

[0008] Based on this, the present invention can miniaturize the six-axis force sensor, making its minimum size reach the micrometer range or even the nanometer range, which is beneficial to expanding the application fields of the six-axis force sensor, enabling it to be applied in probe control, biosensing, etc.

[0009] In a second aspect, the present invention provides a manufacturing method of a six-axis force sensor, including:

[0010] Provide a semiconductor substrate;

[0011] Pattern the semiconductor substrate according to a six - dimensional force sensor pattern, etch out a semiconductor structure layer, and fabricate a six - dimensional force sensor.

[0012] Compared with the prior art, the beneficial effects of the manufacturing method of the six - dimensional force sensor provided by the present invention are the same as those of the six - dimensional force sensor provided in the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0014] Figure 1 Show a schematic structural diagram of the six - dimensional force sensor provided by an embodiment of the present invention;

[0015] Figures 2A to 2B Show a process flow chart of the manufacturing method of the six - dimensional force sensor according to an exemplary embodiment of the present invention;

[0016] Figures 3A to 3B Show a process flow chart of the manufacturing method of the six - dimensional force sensor according to an exemplary embodiment of the present invention in the etching stage. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0019] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined. "Several" means one or more unless otherwise specifically defined.

[0020] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0021] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] As a sensor with complete six-dimensional force and torque in space, the six-axis force sensor plays a crucial role in the process of industrial automation and intelligentization. It can simultaneously measure three force components along the coordinate axes and three torque components around the coordinate axes, identify its environment based on six groups of separated information, and is mainly used for force and force position control, such as welding, grinding, assembly, trajectory tracking, etc. At present, the six-axis force sensor is mainly applied in the field of robotics. Its minimum size is in the millimeter range, which not only limits its application fields but also is not conducive to improving the accuracy and convenience of intelligent control of the measured object according to its force condition.

[0023] In view of the above problems, an embodiment of the present invention provides a six-axis force sensor to expand the application fields of the six-axis force sensor and improve the accuracy and convenience of intelligent control of the measured object according to its force condition. Figure 1 The structural schematic diagram of the six-axis force sensor provided in the embodiment of the present invention is shown. As Figure 1 shown, the six-axis force sensor provided in the embodiment of the present invention includes: a semiconductor substrate 100 and a semiconductor structure layer 200 formed on the semiconductor substrate 100. Among them, the semiconductor substrate 100 is a hollowed-out substrate, and the pattern of the semiconductor structure layer 200 is a six-axis force sensor pattern, and the six-axis force sensor pattern corresponds to the structure of the six-axis force sensor.

[0024] It can be understood that due to the sensitivity of the semiconductor structure, the six-axis force sensor can detect the force condition of the measured object more sensitively, which is beneficial to improving the accuracy of detecting the force condition of the measured object, and thus can improve the accuracy and convenience of intelligent control of the measured object according to its force condition.

[0025] It should be noted that the six-axis force sensor provided by the embodiments of the present invention is fabricated by MEMS technology, enabling the miniaturization of the six-axis force sensor, with its minimum size reaching the micron scale or even the nanometer scale, which is conducive to expanding the application fields of the six-axis force sensor and enabling it to be applied in probe control, biosensing, etc.

[0026] In practical applications, the semiconductor structure layer includes a measurement platform, a plurality of elastic force components, and a plurality of support components;

[0027] Among them, each elastic force component is evenly distributed along the circumferential direction of the measurement platform, each support component is located between two adjacent elastic force components, the elastic force component includes a floating beam and an elastic beam, the end of the floating beam is connected to the support component, and one side of the floating beam facing the measurement platform is connected to the measurement platform through the elastic beam. Among them, each elastic force component is symmetrically distributed, which is conducive to achieving "isotropy" and simplifying the decoupling mathematical model as much as possible, making it applicable to the measurement of loads in all axial directions and ensuring high accuracy. Therefore, when the object to be measured contacts the measurement platform, the elastic beam connected to the measurement platform can sense the forces and torques in all directions received by the object to be measured, and drive the floating beam connected to it to move and stretch or tighten. During this process, three force components along the coordinate axes and three torque components around the coordinate axes can be measured simultaneously, and the environment can be identified based on six sets of separated information. Thanks to the sensitivity of the semiconductor structure, the six-axis force sensor can more intuitively reflect the force condition of the object to be measured, which is conducive to improving the accuracy of detecting the force condition of the object to be measured. It can be understood that in order to better quantify the force condition of the object to be measured, piezoresistive electrodes can be provided on each elastic force component to measure the deformation of each elastic force component, thereby improving the accuracy and convenience of intelligent control of the object to be measured according to its force condition.

[0028] For example: when the object to be measured contacts the measurement platform, the elastic beam connected to the measurement platform can sense the forces and torques in all directions received by the object to be measured, and drive the floating beam connected to it to move and stretch or tighten. During this process, after the piezoresistive electrode detects an external force, its resistance value changes and is then converted into a voltage signal. Based on this, the corresponding force and torque values can be calculated according to the change of the voltage signal.

[0029] The exemplary embodiments of the present invention also provide a manufacturing method of a six-axis force sensor, which can manufacture the six-axis force sensor of the embodiments of the present invention. The manufacturing process of this method is simple and easy to operate, enabling the miniaturization of the six-axis force sensor, with its minimum size reaching the micron scale or even the nanometer scale, which is conducive to expanding the application fields of the six-axis force sensor and enabling it to be applied in probe control, biosensing, etc.

[0030] Figures 2A to 2B Process flowchart showing a method of manufacturing a six-axis force sensor according to an exemplary embodiment of the present invention.

[0031] As Figure 2A shown, a semiconductor substrate 100 is provided. The semiconductor substrate 100 includes a first semiconductor layer 101, a buried oxide layer 102, and a second semiconductor layer 103, wherein the first semiconductor layer 101, the buried oxide layer 102, and the second semiconductor layer 103 are stacked in sequence. The buried oxide layer 102 isolates and avoids most of the parasitic effects existing between the first semiconductor layer 101 and the second semiconductor layer 103, improves the operating speed of the device, reduces leakage and loss, and eliminates the latch-up effect.

[0032] It should be understood that in the embodiments of the present invention, the soi technology is used to obtain the semiconductor substrate. The soi technology can be either the oxygen implantation isolation technology, the silicon wafer bonding and backside etching technology, or the smart cut technology, and can be adjusted according to the actual situation, which is not limited herein. At the same time, the first semiconductor layer and the first semiconductor layer in the embodiments of the present invention can be substrates such as silicon carbide and silicon nitride, which are not limited herein.

[0033] As Figure 2B shown, the semiconductor substrate 100 is hollowed out according to the six-axis force sensor pattern, and a semiconductor structure layer 200 is etched to form a six-axis force sensor.

[0034] To further elaborate on this process, Figures 3A to 3B Process flowchart showing a method of manufacturing a six-axis force sensor according to an exemplary embodiment of the present invention in the etching stage.

[0035] As Figure 3AAs shown, starting from the surface of the second semiconductor layer 103 facing away from the buried oxide layer 102, the second semiconductor layer 103 is patterned according to the six-axis force sensor pattern. At this time, the second semiconductor layer can be lithographically patterned and etched to form the upper part of the six-axis force sensor according to the six-axis force sensor pattern. It is worth noting that in the embodiments of the present invention, the thickness of the buried oxide layer is limited to 300 nm to 5 μm. Within this range, the buried oxide layer can not only play an insulating role and improve the operating speed of the device, but also be used to protect or mask certain regions of the first semiconductor layer and the second semiconductor layer during the process, serving as a support layer for subsequent etching steps to standardize the etching limit of the device and ensure the yield of the six-axis force sensor in the embodiments of the present invention. In the embodiments of the present invention, the thickness of the second semiconductor layer is also limited to 500 nm to 190 μm. It can be seen that through the MEMS process, a six-axis force sensor with dimensions in the micron or even nanometer range can be fabricated, which is beneficial to expanding the application fields of the six-axis force sensor, enabling it to be applied in probe control, biosensing, etc. Within this range, the second semiconductor layer can sensitively sense the forces and torques exerted on the object to be measured and deform according to the force conditions. If the thickness of the second semiconductor layer exceeds 190 μm, the cost will be relatively high, and the detection accuracy cannot be significantly improved. If the thickness of the second semiconductor layer is less than 500 nm, the implementation difficulty of subsequent manufacturing steps will be relatively high, and the stability of the obtained six-axis force sensor will be relatively low.

[0036] As Figure 3B shown, starting from the surface of the first semiconductor layer 101 facing away from the buried oxide layer 102, the first semiconductor layer 101 is patterned according to the six-axis force sensor pattern, the semiconductor structure layer 200 is etched, and a local area of the buried oxide layer 102 is removed to obtain the six-axis force sensor. During this process, the first semiconductor layer needs to be lithographically patterned and etched according to the six-axis force sensor pattern to form the lower part of the six-axis force sensor. The buried oxide layer can standardize the etching limit of the lower device to improve the yield of the six-axis force sensor. Then, a local area of the buried oxide layer 102 needs to be removed according to the six-axis force sensor pattern to obtain the six-axis force sensor. In the embodiments of the present invention, the method for removing the local area of the buried oxide layer is a wet etching process. In this process, the semiconductor substrate needs to be placed in a liquid chemical etching solution for etching. During the etching process, the etching solution will gradually etch and dissolve the local buried oxide layer it contacts through chemical reactions. The etching solution includes hydrofluoric acid. It should be understood that the concentration ratio can be adjusted according to the actual situation and is not limited here.

[0037] The following describes an example of the manufacturing method of the six-axis force sensor according to the exemplary embodiments of the present invention.

[0038] Example 1

[0039] The manufacturing method of the six-axis force sensor gyroscope provided by the embodiment of the present invention includes: providing a semiconductor substrate, which includes a first silicon layer, a silicon dioxide layer, and a second silicon layer, wherein the thickness of the silicon dioxide layer is 300 nm, and the thickness of the second silicon layer is 500 nm. Then, first pattern the surface of the second silicon layer facing away from the silicon dioxide layer according to the six-axis force sensor pattern, and then pattern the surface of the first silicon layer facing away from the silicon dioxide layer according to the six-axis force sensor pattern to etch out the semiconductor structure layer. Finally, use hydrofluoric acid to remove the local area of the silicon dioxide layer to obtain the six-axis force sensor.

[0040] Embodiment 2

[0041] The manufacturing method of the six-axis force sensor gyroscope provided by the embodiment of the present invention includes: providing a semiconductor substrate, which includes a first silicon layer, a silicon dioxide layer, and a second silicon layer, wherein the thickness of the silicon dioxide layer is 800 nm, and the thickness of the second silicon layer is 100 μm. Then, first pattern the surface of the second silicon layer facing away from the silicon dioxide layer according to the six-axis force sensor pattern, and then pattern the surface of the first silicon layer facing away from the silicon dioxide layer according to the six-axis force sensor pattern to etch out the semiconductor structure layer. Finally, use hydrofluoric acid to remove the local area of the silicon dioxide layer to obtain the six-axis force sensor.

[0042] Embodiment 3

[0043] The manufacturing method of the six-axis force sensor gyroscope provided by the embodiment of the present invention includes: providing a semiconductor substrate, which includes a first silicon layer, a silicon dioxide layer, and a second silicon layer, wherein the thickness of the silicon dioxide layer is 1000 nm, and the thickness of the second silicon layer is 100 μm. Then, first pattern the surface of the second silicon layer facing away from the silicon dioxide layer according to the six-axis force sensor pattern, and then pattern the surface of the first silicon layer facing away from the silicon dioxide layer according to the six-axis force sensor pattern to etch out the semiconductor structure layer. Finally, use hydrofluoric acid to remove the local area of the silicon dioxide layer to obtain the six-axis force sensor.

[0044] Embodiment 4

[0045] The manufacturing method of the six-axis force sensor gyroscope provided by the embodiment of the present invention includes: providing a semiconductor substrate, which includes a first silicon layer, a silicon dioxide layer, and a second silicon layer, wherein the thickness of the silicon dioxide layer is 5 μm, and the thickness of the second silicon layer is 190 μm. Then, first pattern the surface of the second silicon layer facing away from the silicon dioxide layer according to the six-axis force sensor pattern, and then pattern the surface of the first silicon layer facing away from the silicon dioxide layer according to the six-axis force sensor pattern to etch out the semiconductor structure layer. Finally, use hydrofluoric acid to remove the local area of the silicon dioxide layer to obtain the six-axis force sensor.

[0046] In the above description, no detailed explanations are given for the technical details such as the composition and etching of each layer. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of the desired shapes. Additionally, in order to form the same structure, those skilled in the art can also design methods that are not exactly the same as the methods described above. Moreover, although the embodiments are described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination.

[0047] The embodiments of the present invention have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present invention.

Claims

1. A manufacturing method of a six-axis force sensor, characterized in that, Including: Providing a semiconductor substrate; the semiconductor substrate includes a first semiconductor layer, a buried oxide layer, and a second semiconductor layer, and the first semiconductor layer, the buried oxide layer, and the second semiconductor layer are stacked in sequence; Starting from the surface of the second semiconductor layer facing away from the buried oxide layer, patterning the second semiconductor layer according to a six-axis force sensor pattern; Starting from the surface of the first semiconductor layer facing away from the buried oxide layer, patterning the first semiconductor layer according to the six-axis force sensor pattern, etching out a semiconductor structure layer and removing a local area of the buried oxide layer to obtain a six-axis force sensor; the semiconductor substrate is a hollowed-out substrate, and the six-axis force sensor is a six-axis force sensor fabricated by MEMS technology.

2. The manufacturing method of the six-axis force sensor according to claim 1, characterized in that The thickness of the buried oxide layer is 300 nm to 5 μm, and the thickness of the second semiconductor layer is 500 nm to 190 μm.

3. The manufacturing method of the six-axis force sensor according to claim 1, characterized in that The way of removing the local area of the buried oxide layer is a wet etching process.

4. The manufacturing method of the six-axis force sensor according to claim 3, characterized in that The reagent used in the wet etching process includes hydrofluoric acid.

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