Packaging structure of force sensor and manufacturing method thereof

Abstract

The present application discloses a packaging structure of a force sensor and a manufacturing method thereof, which relates to the technical field of force sensors and is used to solve the problem of low force transmission sensitivity of existing force sensors. The packaging structure of the force sensor provided in the present application includes a substrate, a first surface of which is provided with a first groove and a second groove arranged at intervals, and a boss is provided at the bottom of the second groove; the device structure is supported on the first surface and includes a movable mass block and an anchor point for fixing the movable mass block, a part of the movable mass block is suspended at the opening end of the first groove, and the other part is fixedly supported on the first surface, the movable mass block constitutes a first electrode plate, and the anchor point is fixed on the boss; the ASIC chip is bonded to the side of the device structure facing away from the substrate, and a second electrode plate is provided on the side surface facing the device structure, and the second electrode plate is opposite to the first electrode plate and is arranged at intervals to form a variable capacitor; wherein a third groove is provided at the bottom of the first groove and / or the bottom of the second groove.

Description

Technical Field

[0001] The present application relates to the technical field related to force sensors, and in particular to a packaging structure of a force sensor and a manufacturing method thereof. Background Art

[0002] A force sensor is a sensor manufactured using MEMS technology, which is used to measure the pressure or force applied to an object. The force sensor chip is usually composed of an elastic structure and a sensitive element. When external pressure is applied, the elastic structure will deform slightly, and the sensitive element will convert the deformation into an electrical signal, which will be processed to obtain the corresponding pressure value.

[0003] The force sensor chip in the packaging structure of the force sensor in the prior art includes a substrate, a device structure arranged on the surface of one side of the substrate, and a cover structure arranged on the side of the device structure facing away from the substrate. The device structure senses the external force applied through the substrate. The substrate in the prior art only includes grooves of the same depth, and the surface area and contact area of ​​the substrate are small, resulting in low force transmission sensitivity of the force sensor. Summary of the invention

[0004] The present application provides a packaging structure of a force sensor and a manufacturing method thereof, which can solve the problem of low force transmission sensitivity of existing force sensors.

[0005] To achieve the above-mentioned purpose, on the one hand, the packaging structure of the force sensor provided by the present application includes:

[0006] A substrate, a first surface of which is provided with first grooves and second grooves arranged at intervals, and a boss is provided at the bottom of the second groove;

[0007] a device structure, contacting and supported on the first surface, the device structure comprising a movable mass block and an anchor point for fixing the movable mass block, a part of the movable mass block is suspended at the opening end of the first groove, and another part is fixedly supported on the first surface, the movable mass block constitutes a first electrode plate, and the anchor point is fixedly arranged on the boss;

[0008] An ASIC chip is bonded to a side of the device structure facing away from the substrate, and a second electrode plate is provided on a surface of the ASIC chip facing the device structure, the second electrode plate is opposite to the first electrode plate and is spaced apart to form a variable capacitor;

[0009] A third groove is provided at the bottom of the first groove and / or the bottom of the second groove, and the ASIC chip collects the first electrical signal of the first electrode plate that changes in response to the movement of the movable mass block, and collects the second electrical signal of the second electrode plate, and outputs a force sensitive signal corresponding to the force sensor based on the changed first electrical signal and the second electrical signal.

[0010] On the other hand, the present application also provides a method for manufacturing a packaging structure of a force sensor, comprising:

[0011] Providing a substrate, forming a first groove and a second groove on a first surface of the substrate, and forming a third groove at the bottom of the first groove and / or the bottom of the second groove, wherein a boss is formed at the bottom of the second groove;

[0012] A device structure is fabricated on the first surface, the device structure comprising a movable mass block and an anchor point for fixing the movable mass block, so that a portion of the movable mass block is suspended at the opening end of the first groove, and another portion is fixedly supported on the first surface, the movable mass block constitutes a first electrode plate, and the anchor point is fixedly supported on the boss;

[0013] Providing an ASIC chip, and manufacturing a second electrode plate on the ASIC chip;

[0014] Bonding the side of the ASIC chip having the second electrode plate to the device structure so that the second electrode plate is opposite to the first electrode plate and spaced apart to form a variable capacitor;

[0015] The ASIC chip collects a first electrical signal of the first electrode plate that changes in response to the movement of the movable mass block, and collects a second electrical signal of the second electrode plate, and outputs a force sensitive signal corresponding to the force sensor based on the changed first electrical signal and the second electrical signal.

[0016] The above technical solution of the present application has at least the following beneficial effects: in specific use, when the side surface of the substrate facing away from the first surface is subjected to an external force, the external force is transmitted to the movable mass block via the part of the movable mass block that contacts the first surface of the substrate, so that the interval between the second electrode plate and the first electrode plate (movable mass block) constituting the variable capacitor changes, and the change in the interval will cause a capacitance change between the second electrode plate and the first electrode plate (movable mass block), and the ASIC chip outputs a force sensitive signal corresponding to the force sensor based on the collected changed first electrical signal and the second electrical signal, so as to sense the external force applied from the outside. In addition, since a third groove is provided at the bottom of the first groove and / or the second groove, the distribution of the strain field on the substrate can be changed by making grooves of different depths in the substrate, and grooves of different depths will result in different softness in different areas of the substrate, thereby adjusting the sensitivity of the force sensor, and grooves of different depths can increase the surface area and contact area of ​​the substrate, increase the transmission effect of the force acting on the substrate surface, and improve the force transmission sensitivity of the force sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 It is a schematic structural diagram of a substrate, a device structure and an ASIC chip in the packaging structure of a force sensor in an embodiment of the present application;

[0019] Figure 2 is a schematic structural diagram of a substrate and a device structure in an embodiment of the present application;

[0020] Figure 3 is a top view of the movable mass block, anchor point and elastic connection part in the device structure in the embodiment of the present application;

[0021] Figure 4 is a schematic structural diagram of the packaging structure of the force sensor in an embodiment of the present application;

[0022] Figure 5 It is one of the flow charts of the method for manufacturing the packaging structure of the force sensor in the embodiment of the present application;

[0023] Figure 6 It is one of the process schematic diagrams of the packaging structure manufacturing method of the force sensor in the embodiment of the present application;

[0024] Figure 7 This is the second flow chart of the method for manufacturing the packaging structure of the force sensor in the embodiment of the present application;

[0025] Figure 8 This is the second process schematic diagram of the method for manufacturing the packaging structure of the force sensor in the embodiment of the present application;

[0026] Fig. 9 This is the third process schematic diagram of the method for manufacturing the packaging structure of the force sensor in the embodiment of the present application.

[0027] The main reference numerals in the drawings of this application specification are described as follows:

[0028] 1-substrate; 11-first groove; 12-second groove; 121-boss; 13-third groove;

[0029] 2-device structure; 21-movable mass block; 211-protrusion; 22-anchor point; 23-first bonding body; 24-elastic connecting part; 25-support part; 26-first conductive part;

[0030] 3-ASIC chip; 31-first conductive via; 32-second conductive via; 33-second bonding body; 34-third metal layer; 35-second conductive portion;

[0031] 4-conductive circuit layer; 41-first circuit; 42-second circuit; 43-second electrode;

[0032] 5-Insulation layer;

[0033] 6-conductive structure; 61-passivation layer; 62-metal conductive layer; 63-solder ball;

[0034] 7-substrate; 71-conductive terminal. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0036] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply 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 understood as a limitation on the present application.

[0037] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0038] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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, a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0039] The present application provides a packaging structure of a force sensor and a manufacturing method thereof, which are described in detail below. It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments of the present application. In the following embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0040] Reference Figure 1 The packaging structure of the force sensor provided in the present application includes a substrate 1, a device structure 2 and an ASIC chip 3. The first surface of the substrate 1 is provided with a first groove 11 and a second groove 12 arranged at intervals, and a boss 121 is provided at the bottom of the second groove 12. The device structure 2 contacts and is supported on the first surface. The device structure 2 includes a movable mass block 21 and an anchor point 22 for fixing the movable mass block 21. A part of the movable mass block 21 is suspended at the open end of the first groove 11, and the other part is fixedly supported on the first surface. The movable mass block 21 constitutes a first electrode plate, and the anchor point 22 is fixed on the boss 121. The ASIC chip 3 is bonded to the side of the device structure 2 facing away from the substrate 1, and a second electrode plate 43 is provided on the side surface of the ASIC chip 3 facing the device structure 2. The second electrode plate 43 is opposite to the first electrode plate and is arranged at intervals to form a variable capacitor. Among them, a third groove 13 is provided at the bottom of the first groove 11 and / or the second groove 12, and the ASIC chip 3 collects the first electrical signal of the first electrode plate that changes in response to the movement of the movable mass block 21, and collects the second electrical signal of the second electrode plate 43, and outputs a force sensitive signal corresponding to the force sensor based on the changed first electrical signal and the second electrical signal.

[0041] In specific use, when the side surface of the substrate 1 facing away from the first surface is subjected to an external force, the external force is transmitted to the movable mass block 21 via the portion of the movable mass block 21 that contacts the first surface of the substrate 1, so that the interval between the second electrode plate 43 and the first electrode plate (movable mass block 21) constituting the variable capacitor changes, and the change in the interval causes a capacitance change between the second electrode plate 43 and the first electrode plate (movable mass block 21), and the ASIC chip 3 outputs a force sensitive signal corresponding to the force sensor based on the collected first electrical signal and the second electrical signal, so as to sense the external force applied from the outside. In addition, since a third groove 13 is provided at the bottom of the first groove 11 and / or the second groove 12, the distribution of the strain field on the substrate 1 can be changed by making grooves of different depths in the substrate 1, and grooves of different depths will result in different softness in different areas of the substrate 1, thereby adjusting the sensitivity of the force sensor, and grooves of different depths can increase the surface area and contact area of ​​the substrate 1, increase the transmission effect of the force acting on the substrate surface, and improve the force transmission sensitivity of the force sensor.

[0042] In addition, the present application bonds the side of the ASIC chip 3 having the second electrode plate 43 to the side of the device structure 2 facing away from the substrate 1. On the one hand, the above arrangement can ensure that the ASIC chip 3, the device structure 2 and the substrate 1 are stacked in the thickness direction of the substrate 1, and the orthographic projection areas of the ASIC chip 3 and the device structure 2 in the thickness direction overlap with the orthographic projection area of ​​the substrate 1 in the thickness direction, thereby reducing the occupied area of ​​the three, which is the area of ​​the surface of the side of the ASIC chip 3 facing away from the device structure 2. On the other hand, the above arrangement can make the ASIC chip 3 constitute the packaging structure of the device structure 2, so that there is no need to use an additional cover structure to package the device structure 2, which is conducive to simplifying the manufacturing process of the packaging structure of the force sensor and reducing its manufacturing cost.

[0043] Please continue to refer to Figure 1 In the present application, a third groove 13 is provided at the bottom of each of the first groove 11 and the second groove 12. Of course, it is not excluded that only one third groove 13 may be provided at the bottom of the first groove 11, or only one third groove 13 may be provided at the bottom of the second groove 12. Alternatively, multiple third grooves 13 may be provided at the bottom of the first groove 11 and / or the second groove 12, and the multiple third grooves 13 may have different depths.

[0044] For example, in order to further ensure the force transmission effect and sensitivity of the substrate 1, the distance between the bottom of the first groove 11 in the substrate 1 and the second surface of the substrate 1 is 50um~200um, the first groove 11 and the second groove 12 have the same depth, the second surface and the first surface are arranged opposite to each other, and the second surface is used to withstand external force. The second surface of the substrate 1 is deformed by the external force, thereby driving the movable mass block 21 to move, and realizing the force transmission effect of the force sensor. The height of the boss 121 is the same as the depth of the second groove 12, and there is a gap between the boss 121 and the groove wall of the second groove 12.

[0045] Reference Figure 2 The movable mass block 21 is provided with a plurality of protrusions 211 on one side of the surface facing the second electrode plate 43. The height of the plurality of protrusions 211 is less than the interval between the second electrode plate 43 and the first electrode plate, thereby being able to reduce the interval between the second electrode plate 43 and the first electrode plate to a certain extent, so as to improve the detection sensitivity of the force sensor. At the same time, the protrusions 211 can reduce the contact area between the second electrode plate 43 and the first electrode plate when the two accidentally contact, play a certain mechanical limiting role, and improve the detection reliability of the force sensor.

[0046] It should be noted that after the protrusion 211 is provided, there is still a gap between the second electrode plate 43 and the first electrode plate, but the gap between the second electrode plate 43 and the first electrode plate is smaller than the gap between the second electrode plate 43 and the first electrode plate when the protrusion 211 is not provided. The protrusion 211 is only used to reduce the gap between the second electrode plate 43 and the first electrode plate, rather than eliminating the gap between the second electrode plate 43 and the first electrode plate.

[0047] Based on the above embodiment, the heights of the plurality of protrusions 211 are the same in the direction from the movable mass block 21 to the second electrode plate 43, and the height of each protrusion 211 satisfies: 0.5um~2um. When the height of the protrusion 211 is between 0.5um and 2um, it can not only reduce the interval between the second electrode plate 43 and the first electrode plate, but also prevent the second electrode plate 43 from contacting the first electrode plate caused by the deformation of the substrate 1 during normal use. For example, the plurality of protrusions 211 are arranged in an array, that is, the spacing between each two adjacent protrusions 211 is equal.

[0048] Continue to refer to Figure 1 ASIC chip 3 includes a first conductive via 31 and a second conductive via 32. A conductive circuit layer 4 is provided on one side of the surface of ASIC chip 3 facing the device structure 2. The conductive circuit layer 4 includes a first circuit 41, a second circuit 42, and a second electrode 43. The first conductive via 31 is electrically connected to the first circuit 41 to form a first conductive path. The second conductive via 32 is electrically connected to the second circuit 42 to form a second conductive path. The force sensor applies a first bias voltage to the first electrode through the first conductive path, and applies a second bias voltage to the second electrode 43 through the second conductive path. At the same time, ASIC chip 3 collects a first electrical signal of the first electrode that changes in response to the movement of the movable mass block 21 through the first conductive path, and collects a second electrical signal of the second electrode 43 through the second conductive path, so as to realize the electrical communication function of the force sensor. Moreover, by directly connecting the device structure 2 and the external circuit through the first conductive via 31 and the second conductive via 32, it can be ensured that the components electrically connected through ASIC chip 3 have a shorter interconnection distance.

[0049] It can be understood that the above-mentioned ASIC chip 3 has a first signal port, a second signal port and a third signal port, the first signal port is electrically connected to the first conductive path, the second signal port is electrically connected to the second conductive path, the first signal port is used to collect the first electrical signal of the first electrode plate that changes in response to the movement of the movable mass block 21 through the first conductive path, and the second signal port collects the second electrical signal of the second electrode plate 43 through the second conductive path. Subsequently, the changed first electrical signal and the second electrical signal are calculated and amplified, and the force sensitive signal corresponding to the force sensor is output through the third signal port.

[0050] Among them, the first electrode plate (movable mass block 21) is electrically connected to the first conductive path through the anchor point 22, so that the force sensor applies a first bias voltage to the first electrode plate through the first conductive path without wire bonding the first electrode plate and the first conductive path. In addition, the anchor point 22 can not only fix the movable mass block 21, but also provide the first bias voltage to the movable mass block 21 as a conductor, making the circuit layout of the force sensor neater and clearer. For example, the first electrode plate (movable mass block 21) is electrically connected to the first conductive path through the anchor point 22, which can realize the conductive performance of the anchor point 22 by making the anchor point 22 of a conductive material, or coating a conductive layer on the periphery of the anchor point 22 to make it conductive.

[0051] It can be understood that the anchor point 22 and the movable mass block 21 of the present application are installed and supported on the same plane. In other words, both are arranged on the first surface, which facilitates the manufacture of the device structure 2 and can also ensure that the connection structure between the two is simple.

[0052] Combination Figure 2 and Figure 3 In order to realize the connection between the anchor point 22 and the movable mass block 21, the device structure 2 further includes an elastic connection portion 24 connected between the movable mass block 21 and the anchor point 22, and the movable mass block 21 and the anchor point 22 are connected through the elastic connection portion 24 to jointly constitute a force sensitive unit of the device structure 2. Among them, the anchor point 22 is used to realize the subsequent electrical signal conduction, and the elastic connection portion 24 is located at the open end of the second groove 12, and the second groove 12 can provide a deformation space for the deformation of the elastic connection portion 24.

[0053] It should be noted that, refer to Figure 2 and Figure 3 The device structure 2 further includes a support portion 25 arranged around the movable mass block 21, the anchor point 22 and the elastic connection portion 24. The elastic connection portion 24 enables the movable mass block 21 to be displaced relative to the anchor point 22 when a force is applied. In addition, by providing the support portion 25, on the one hand, the movable mass block 21, the anchor point 22 and the elastic connection portion 24 arranged inside it can be protected, and on the other hand, it is convenient to make other functional layers on the side surface facing away from the substrate 1 in the subsequent process to seal the movable mass block 21, the anchor point 22 and the elastic connection portion 24 arranged inside it, so that it can be used in an environment with temperature and humidity, and ensure that the detection accuracy and sensitivity of the force sensor are not affected by the external environment.

[0054] Among them, all the components in the above-mentioned device structure 2 are arranged in the same layer to ensure that the packaging structure of its force sensor is compact in size in the thickness direction. The device structure 2 is obtained by thinning the silicon layer arranged on the first surface. In order to ensure the force transmission effect from the substrate 1 to the device structure 2, the thickness of the device structure 2 is thinned to 10um~100um.

[0055] Please continue to refer to Figure 1 In some embodiments of the present application, the packaging structure of the force sensor further includes an insulating layer 5, which is disposed between the substrate 1 and the device structure 2, or the insulating layer 5 covers the first surface of the substrate 1, and the side surface of the boss 121 for supporting the anchor point 22. With the above arrangement, on the one hand, the substrate 1 can be protected and separated from the remaining components to provide electrical insulation to the first surface and prevent current from being conducted between the substrate 1 and the external environment. On the other hand, by providing the insulating layer 5, the performance of the substrate 1 can be changed, for example, the hardness, wear resistance and corrosion resistance of the substrate 1 can be improved, thereby improving the stability, reliability and accuracy of the force sensor.

[0056] For example, the insulating layer 5 is a silicon oxide layer, an aluminum oxide layer, a zinc oxide layer or a titanium oxide layer. Its thickness is 0.1um to 2um, and it is used for bonding with the device structure 2. Alternatively, the insulating layer 5 covers all the wall surfaces of the substrate 1 facing the device structure 2. In other words, the first surface of the substrate 1 is covered with the insulating layer 5. Figure 1 and Figure 2 As shown, in an embodiment in which the substrate 1 includes a first groove 11, a second groove 12, a boss 121 and a third groove 13, the groove wall of the first groove 11, the groove wall of the second groove 12, the wall surface of the boss 121 and the groove wall of the third groove 13 are all covered with an insulating layer 5.

[0057] Reference Figure 1 and Figure 2 In order to achieve bonding between the device structure 2 and the ASIC chip 3, a first bonding body 23 is provided on the side of the device structure 2 facing the ASIC chip 3, and a second bonding body 33 is provided on the side of the ASIC chip 3 facing the device structure 2. The device structure 2 and the ASIC chip 3 are bonded by the first bonding body 23 and the second bonding body 33, so as to seal the movable mass block 21, the elastic structure 24 and the anchor point 22 in the device structure 2 in the area enclosed by the bonding of the device structure 2 and the ASIC chip 3 by the first bonding body 23 and the second bonding body 33. For example, the first bonding body 23 and the second bonding body 33 can both be made of the metal material gold, or one of the first bonding body 23 and the second bonding body 33 can be made of the metal material aluminum, and the other can be made of the metal material germanium.

[0058] Among them, the first circuit 41 and the second circuit 42 are both located in the area enclosed by the first bonding body 23 and the second bonding body 33 to provide electromagnetic shielding for the conductive circuit layer 4. The area enclosed by the first bonding body 23 and the second bonding body 33 can protect the first circuit 41 and the second circuit 42 from the influence of external physical forces and provide mechanical protection thereto to enhance the safety and reliability of the conductive circuit layer 4.

[0059] In some other embodiments of the present application, the orthographic projections of the first conductive via 31 and the second conductive via 32 on the first surface of the substrate 1 are located within the orthographic projection area of ​​the area enclosed by the first bonding body 23 and the second bonding body 33 on the first surface of the substrate 1. That is, the first conductive via 31 and the second conductive via 32 are located inside the first bonding body 23 and / or the second bonding body 33.

[0060] Reference Figure 1 and Figure 4 A conductive structure 6 is provided on the side of the ASIC chip 3 facing away from the device structure 2. The conductive structure 6 is electrically connected to the first conductive path and the second conductive path respectively. The conductive structure 6 is provided to facilitate the electrical connection between the first conductive path and the second conductive path and the external structure. For example, the conductive structure 6 includes a passivation layer 61, a metal conductive layer 62, and a plurality of solder balls 63. The passivation layer 61 covers the surface of the side of the ASIC chip 3 facing away from the device structure 2. The metal conductive layer 62 covers the surface of the side of the passivation layer 61 facing away from the ASIC chip 3. The plurality of solder balls 63 are all provided on the metal conductive layer 62 and are electrically connected to the first conductive path and the second conductive path respectively through two conductive lines in the metal conductive layer 62.

[0061] Based on the above embodiment, the packaging structure of the force sensor also includes a substrate 7, and a plurality of conductive terminals 71 are provided on one side of the substrate 7. The plurality of conductive terminals 71 are electrically connected to the first conductive path and the second conductive path respectively through the conductive structure 6, so as to apply a first bias voltage to the first electrode plate through the first conductive path, and apply a second bias voltage to the second electrode plate through the second conductive path.

[0062] At the same time, when the stacked substrate 1, device structure 2 and ASIC chip 3 are arranged as a whole on the base plate 7, the occupied area of ​​the base plate 7 is the area of ​​the surface of the ASIC chip 3 facing the base plate 7, which is conducive to reducing the occupied area of ​​the base plate 7. At the same time, there is no need to wire the ASIC chip and the device structure 2, which is conducive to simplifying the manufacturing process.

[0063] Reference Figure 5 and Figure 6The present application also provides a method for manufacturing a packaging structure of a force sensor, the manufacturing method comprising: providing a substrate 1, making a first groove 11 and a second groove 12 on a first surface of the substrate 1, and making a third groove 13 at the bottom of the first groove 11 and / or the bottom of the second groove 12, and a boss 121 is formed at the bottom of the second groove 12; making a device structure 2 on the first surface, the device structure 2 comprising a movable mass block 21 and an anchor point 22 for fixing the movable mass block 21, so that a part of the movable mass block 21 is suspended at the opening end of the first groove 11, and the other part is fixedly supported on the first surface, the movable mass block 21 constitutes a first electrode plate, and the anchor point 22 is fixedly supported on the boss 121; providing an ASIC chip 3, and making a second electrode plate 43 on the ASIC chip 3; bonding a side of the ASIC chip 3 having the second electrode plate 43 to the device structure 2, so that the second electrode plate 43 is opposite to the first electrode plate and is spaced apart to constitute a variable capacitor. Among them, the ASIC chip 3 collects the first electrical signal of the first electrode plate that changes in response to the movement of the movable mass block 21, and collects the second electrical signal of the second electrode plate 43, and outputs a force sensitive signal corresponding to the force sensor based on the changed first electrical signal and the second electrical signal.

[0064] In specific use, when the side surface of the substrate 1 facing away from the first surface is subjected to an external force, the external force is transmitted to the movable mass block 21 via the portion of the movable mass block 21 that contacts the first surface of the substrate 1, so that the interval between the second electrode plate 43 and the first electrode plate (movable mass block 21) constituting the variable capacitor changes, and the change in the interval causes a capacitance change between the second electrode plate 43 and the first electrode plate (movable mass block 21), and the ASIC chip 3 outputs a force sensitive signal corresponding to the force sensor based on the collected first electrical signal and the second electrical signal, so as to sense the external force applied from the outside. In addition, since a third groove 13 is provided at the bottom of the first groove 11 and / or the second groove 12, the distribution of the strain field on the substrate 1 can be changed by making grooves of different depths in the substrate 1, and grooves of different depths will result in different softness in different areas of the substrate 1, thereby adjusting the sensitivity of the force sensor, and grooves of different depths can increase the surface area and contact area of ​​the substrate 1, increase the transmission effect of the force acting on the substrate surface, and improve the force transmission sensitivity of the force sensor.

[0065] Based on the above embodiment, before the step of bonding the side of the ASIC chip 3 having the second electrode plate 43 to the device structure 2, it also includes: making a plurality of protrusions 211 on the surface of the movable mass block 21 facing the second electrode plate 43, and making the height of the plurality of protrusions 211 smaller than the interval between the second electrode plate 43 and the first electrode plate, so as to reduce the interval between the second electrode plate 43 and the first electrode plate to a certain extent, so as to improve the detection sensitivity of the force sensor. At the same time, the protrusions 211 can reduce the contact area between the second electrode plate 43 and the first electrode plate when the two accidentally contact, play a certain mechanical limiting role, and improve the detection reliability of the force sensor.

[0066] The step of providing the ASIC chip 3 specifically includes: providing the ASIC chip 3, making a first conductive via 31, a second conductive via 32 and a conductive circuit layer 4 on the ASIC chip 3, the conductive circuit layer 4 including a first circuit 41, a second circuit 42 and a second electrode 43, and electrically connecting the first conductive via 31 with the first circuit 41 to form a first conductive path, and electrically connecting the second conductive via 32 with the second circuit 42 to form a second conductive path. The force sensor applies a first bias voltage to the first electrode through the first conductive path, and applies a second bias voltage to the second electrode 43 through the second conductive path; the ASIC chip 3 collects a first electrical signal of the first electrode that changes in response to the movement of the movable mass block 21 through the first conductive path, and collects a second electrical signal of the second electrode 43 through the second conductive path, and outputs a force sensitive signal corresponding to the force sensor based on the changed first electrical signal and the second electrical signal, so as to realize the electrical communication function of the force sensor. In addition, by directly connecting the device structure 2 and the external circuit through the first conductive via 31 and the second conductive via 32, it can be ensured that the components electrically connected through the ASIC chip 3 have a shorter interconnection distance.

[0067] At the same time, the side of the ASIC chip 3 having the conductive circuit layer 4 (the second electrode 43) is bonded to the side of the device structure 2 facing away from the substrate 1. On the one hand, the ASIC chip 3, the device structure 2 and the substrate 1 are stacked along the thickness direction of the substrate 1, and the orthographic projection areas of the ASIC chip 3 and the device structure 2 in the thickness direction overlap with the orthographic projection area of ​​the substrate 1 in the thickness direction, thereby reducing the occupied area of ​​the three, which is the area of ​​the surface of the side of the ASIC chip 3 facing away from the device structure 2. On the other hand, the ASIC chip 3 constitutes the packaging structure of the device structure 2, so there is no need to use an additional packaging structure to package it, which simplifies the manufacturing process and manufacturing cost of the packaging structure of the force sensor.

[0068] Based on the above embodiment, after completing the step of bonding the side of the ASIC chip 3 having the second electrode plate 43 to the device structure 2, the manufacturing method further includes: thinning the body of the substrate 1 from the side of the substrate 1 away from the first surface, so as to adjust the force transmission sensitivity through the thinned thickness of the substrate 1. Usually, the thickness of the thinned substrate 1 is 50um~200um, and the thickness refers to the distance between the bottom of the first groove 11 and the side surface of the substrate 1 facing away from the first surface.

[0069] Among them, combined Figure 6~Figure 7 In order to realize the bonding between the ASIC chip 3 and the device structure 2, the step of bonding the side of the ASIC chip 3 having the second electrode plate 43 to the device structure 2 specifically includes: making a first metal layer on the side of the device structure 2 facing away from the substrate 1; patterning the first metal layer to obtain a first bonding body 23; making a second metal layer on the side of the ASIC chip 3 facing the device structure 2; patterning the second metal layer to obtain a second bonding body 33 and a second electrode plate 43, and the second bonding body 33 is arranged around the outer periphery of the second electrode plate 43; bonding the first bonding body 23 and the second bonding body 33 so that the second electrode plate 43 is opposite to the first electrode plate and is arranged at intervals to form a variable capacitor, so that the device structure 2 is packaged through the ASIC chip 3 without the need for an additional packaging structure. At the same time, the second bonding body 33 and the second electrode plate 43 are obtained synchronously by patterning the second metal layer, which is conducive to simplifying the manufacturing process of the packaging structure of the force sensor.

[0070] Please continue to refer to Figure 5 and Figure 6 , before the step of making the device structure on the first surface of the substrate 1, it also includes: making an insulating layer 5 on the first surface; making a functional layer on the surface of the insulating layer 5 on the side facing away from the substrate 1, and thinning the functional layer and then patterning it to obtain a device structure 2, the device structure 2 includes a movable mass block 21 and an anchor point 22 for fixing the movable mass block 21, and a part of the movable mass block 21 is suspended at the open end of the first groove 11, and the other part is fixedly supported on the first surface, the movable mass block 21 constitutes a first electrode, and the anchor point 22 is fixedly supported on the boss 121; making a first metal layer on the side of the device structure 2 facing away from the substrate 1; patterning the first metal layer to obtain a first bonding body 23 and a first conductive portion 26, and the first bonding body 23 is arranged around the periphery of the first conductive portion 26, and the first conductive portion 26 is located on the anchor point 22. The insulating layer 5 formed on the first surface can achieve insulation for the substrate 1 on the one hand, and facilitate bonding between it and the functional layer on the other hand. Thinning the functional layer is beneficial to improving its force transmission effect and subsequent electrical signal conduction.

[0071] The device structure 2 includes a movable mass block 21, an anchor point 22 for fixing the movable mass block 21, an elastic connection portion 24 connecting the movable mass block 21 and the anchor point 22, and a support portion 25. The movable mass block 21, the anchor point 22 and the elastic connection portion 24 together constitute a force sensitive unit, and the support portion 25 is arranged around the periphery of the force sensitive unit to provide physical structural protection for the force sensitive unit.

[0072] Please refer to Figure 1 and Figure 8 The manufacturing of the first conductive via 31, the second conductive via 32 and the conductive circuit layer 4 on the ASIC chip specifically includes: etching the pattern formed on the ASIC chip 3 by deep trench reflection using a deep trench reflection ion etching (DRIE) process on the ASIC chip 3 to obtain the first conductive via 31 and the second conductive via 32, and making the first conductive via 31 and the second conductive via 32 close to the end of the device structure 2 exposed outside the ASIC chip 3; depositing silicon oxide on the surface of the first conductive via 31 and the second conductive via 32 (for example, by plasma TEOS deposition (PETEOS) or thermal oxidation process); fill the first conductive via 31 and the second conductive via 32 with a conductive material, and pre-embed the electrically conductive first conductive via 31 and the second conductive via 32; deposit a third metal layer 34 at the ends of the first conductive via 31 and the second conductive via 32 exposed outside the ASIC chip 3, and make a second metal layer on the side of the third metal layer 34 away from the ASIC chip 3, and perform a patterning process on the second metal layer to obtain a second bonding body 33 and a second electrode plate 43, so as to achieve bonding between the second bonding body 33 in the second metal layer and the first bonding body 23, so as to achieve sealing of the device structure 2.

[0073] Reference Figure 7 and Figure 8 , the second metal layer can be patterned to obtain the second conductive part 35, and the second conductive part 35 is located inside the second bonding body 33; the first bonding body 23 and the second bonding body 33 are bonded to make the first conductive part 26 and the second conductive part 35 contact and conduct. Among them, the first conductive part 26 is directly obtained by patterning the first metal layer, and the first conductive part 26 and the second conductive part 35 contact and conduct, which can simplify the electrical connection structure between the anchor point 22 and the first line 41, and facilitate the electrical connection between it and the first conductive part 26 or the anchor point 22.

[0074] Reference Figure 4 and Fig. 9After completing the step of bonding the side of the ASIC chip 3 having the conductive circuit layer 4 to the device structure 2, the method further includes: grinding the body of the ASIC chip 3 from the side of the ASIC chip 3 facing away from the device structure 2, so that the ends of the first conductive via 31 and the second conductive via 32 located inside the body of the ASIC chip 3 are exposed outside the body of the ASIC chip 3; making a conductive structure 6 on the surface of the side of the ASIC chip 3 facing away from the device structure 2; providing a substrate 7, and electrically connecting the conductive structure 6 and the substrate 7 to complete the overall packaging of the packaging structure of the force sensor. Making the conductive structure 6 on the surface of the side of the ASIC chip 3 facing away from the device structure 2, and electrically connecting the conductive structure 6 and the substrate 7, is conducive to establishing a reliable electrical connection between the ASIC chip 3 and the device structure 2, expanding the connection capacity of the ASIC chip 3, and can also improve the application flexibility and reliability of the ASIC chip 3 in the circuit system.

[0075] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0076] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims. In addition, the specification uses specific examples to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and its core idea of ​​the present application. The content of this specification should not be understood as a limitation on the present application.

Claims

1. A packaging structure of a force sensor, characterized in that: include: A substrate, a first surface of which is provided with first grooves and second grooves arranged at intervals, and a boss is provided at the bottom of the second groove; a device structure, contacting and supported on the first surface, the device structure comprising a movable mass block and an anchor point for fixing the movable mass block, a part of the movable mass block is suspended at the opening end of the first groove, and another part is fixedly supported on the first surface, the movable mass block constitutes a first electrode plate, and the anchor point is fixedly arranged on the boss; An ASIC chip is bonded to a side of the device structure facing away from the substrate, and a second electrode plate is provided on a surface of the ASIC chip facing the device structure, the second electrode plate is opposite to the first electrode plate and is spaced apart to form a variable capacitor; Among them, a third groove is provided at the bottom of the first groove and / or the bottom of the second groove, the first groove has a first groove depth from its bottom to the first surface, the second groove has a second groove depth from its bottom to the first surface, and the third groove has a third groove depth from its bottom to the first surface, and the third groove depth is greater than the first groove depth and greater than the second groove depth. The ASIC chip collects the first electrical signal of the first electrode plate that changes in response to the movement of the movable mass block, and collects the second electrical signal of the second electrode plate, and outputs a force sensitive signal corresponding to the force sensor based on the changed first electrical signal and the second electrical signal.

2. The packaging structure of the force sensor according to claim 1, characterized in that: A plurality of protrusions are provided on a surface of the movable mass block facing the second electrode plate, and a height of the plurality of protrusions is smaller than a distance between the second electrode plate and the first electrode plate.

3. The packaging structure of the force sensor according to claim 2, characterized in that: In the direction from the movable mass block to the second electrode plate, the heights of the plurality of protrusions are the same, and the height of each of the protrusions satisfies: 0.5um~2um.

4. The packaging structure of the force sensor according to claim 1, characterized in that: The ASIC chip includes a first conductive via and a second conductive via. A conductive circuit layer is provided on a surface of the ASIC chip facing the device structure. The conductive circuit layer includes a first circuit, a second circuit and the second electrode plate. The first conductive via is electrically connected to the first circuit to form a first conductive path. The second conductive via is electrically connected to the second circuit to form a second conductive path. The force sensor applies a first bias voltage to the first electrode plate through the first conductive path, and applies a second bias voltage to the second electrode plate through the second conductive path. The ASIC chip collects a first electrical signal of the first electrode plate that changes in response to the movement of the movable mass block through the first conductive path, and collects a second electrical signal of the second electrode plate through the second conductive path.

5. The packaging structure of the force sensor according to claim 4, characterized in that: The first electrode plate is electrically connected to the first conductive path through the anchor point.

6. The packaging structure of the force sensor according to claim 1, characterized in that: Also includes: An insulating layer covers the first surface of the substrate and a side surface of the boss for supporting the anchor point.

7. The packaging structure of the force sensor according to claim 4, characterized in that: A first bonding body is provided on a side of the device structure facing the ASIC chip, and a second bonding body is provided on a side of the ASIC chip facing the device structure. The device structure and the ASIC chip are bonded via the first bonding body and the second bonding body, and the first circuit and the second circuit are both located within an area enclosed by the first bonding body and the second bonding body.

8. The packaging structure of the force sensor according to claim 4, characterized in that: A conductive structure is provided on a side of the ASIC chip facing away from the device structure, and the conductive structure is electrically connected to the first conductive path and the second conductive path respectively.

9. The packaging structure of the force sensor according to claim 8, characterized in that: Also includes: A substrate, one side of which is provided with a plurality of conductive terminals, and the plurality of conductive terminals are respectively electrically connected to the first conductive path and the second conductive path through the conductive structure.

10. A method for manufacturing a packaging structure of a force sensor, characterized in that: include: Providing a substrate, making a first groove and a second groove on a first surface of the substrate, and making a third groove at the groove bottom of the first groove and / or the groove bottom of the second groove, wherein the first groove has a first groove depth from the groove bottom to the first surface, the second groove has a second groove depth from the groove bottom to the first surface, and the third groove has a third groove depth from the groove bottom to the first surface, the third groove depth is greater than the first groove depth and greater than the second groove depth, and a boss is formed at the groove bottom of the second groove; A device structure is fabricated on the first surface, the device structure comprising a movable mass block and an anchor point for fixing the movable mass block, so that a portion of the movable mass block is suspended at the opening end of the first groove, and another portion is fixedly supported on the first surface, the movable mass block constitutes a first electrode plate, and the anchor point is fixedly supported on the boss; Providing an ASIC chip, and manufacturing a second electrode plate on the ASIC chip; Bonding the side of the ASIC chip having the second electrode plate to the device structure so that the second electrode plate is opposite to the first electrode plate and spaced apart to form a variable capacitor; The ASIC chip collects a first electrical signal of the first electrode plate that changes in response to the movement of the movable mass block, and collects a second electrical signal of the second electrode plate, and outputs a force sensitive signal corresponding to the force sensor based on the changed first electrical signal and the second electrical signal.

11. The method for manufacturing a packaging structure of a force sensor according to claim 10, characterized in that: After completing the step of bonding the side of the ASIC chip having the second electrode plate to the device structure, the manufacturing method further includes: The body of the substrate is thinned from a side of the substrate away from the first surface.

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