Airflow sensor, preparation method thereof and electronic device
By opening airflow channels on the sacrificial layer and stacking and bonding of microsensors with integrated circuit chips, the problems of large sensor sizes lead to high costs and poor structural stability are solved, and a smaller size and a more stable structure are achieved.
Patent Information
- Application Number
- CN202310976193.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-03
- Publication Date
- 2025-02-14
AI Technical Summary
With a certain sensitivity of existing airflow sensors, the larger the sensor size, the fewer dies are scribed per unit wafer, resulting in an increase in the cost of a single sensor. At the same time, holes are opened on the ASIC to ensure the flow of airflow, which affects the stability of the structure. and increases the difficulty of preparation.
An airflow sensor was designed. By opening a through airflow channel on the sacrificial layer, combining the stacking and bonding of microsensors and integrated circuit chips, the overall size of the sensor is reduced and holes are avoided in the integrated circuit chip, ensuring that Its integrity and stability.
It realizes reducing sensor size and manufacturing difficulty, while ensuring the integrity and stability of integrated circuit chips and reducing costs.
Smart Images
Figure CN119437526A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of semiconductor devices, and in particular to an airflow sensor and a preparation method thereof, and an electronic device. Background Art
[0002] At present, the market for micro-electro-mechanical system (MEMS) devices, especially sensors, has increased dramatically; the consumer market represented by MEMS microphones, pressure sensors, temperature sensors, airflow sensors, etc. has been released, and the market scale has gradually expanded. However, under the condition of a certain sensitivity, the larger the sensor size, the fewer dies (bare crystals) are diced from a unit wafer, which will lead to an increase in the cost of a single sensor.
[0003] In the related art, a solution of stacking MEMS and application specific integrated circuit (ASIC) together to reduce the occupied space is adopted. However, in order to ensure the flow of air, holes are opened on the ASIC, which affects the stability of the structure and increases the difficulty of preparation. Summary of the invention
[0004] The present application is proposed to solve at least one of the above problems. According to one aspect of the present application, the present application provides an airflow sensor, which includes: a microsensor, the microsensor includes a substrate, a back plate formed on the substrate, a diaphragm formed on the back plate, and a sacrificial layer formed on the diaphragm, wherein an airflow channel penetrating the sacrificial layer is formed on the sacrificial layer; a first groove is formed on the substrate and the back plate, a second groove is formed on the sacrificial layer, and part of the diaphragm is located between the first groove and the second groove; an integrated circuit chip, the integrated circuit chip and the microsensor are bonded to form an integrated module, wherein the integrated circuit chip is stacked on the sacrificial layer; a packaging component, the integrated module is packaged by the packaging component.
[0005] Exemplarily, the packaging assembly includes a substrate and a shell disposed on the substrate, the substrate and the shell are fixed on the substrate, a receiving space is formed between the shell and the substrate, and the integrated module is located in the receiving space.
[0006] Exemplarily, a first air hole and a second air hole are respectively provided on the housing and the substrate, and the second air hole is communicated with the first groove.
[0007] Exemplarily, the substrate and the integrated circuit chip are electrically connected via leads, or the substrate and the microsensor are electrically connected via solder balls.
[0008] Exemplarily, the air flow channel passes through at least two sides of the sacrificial layer, and a portion of the surface of the diaphragm contacts the air flow channel.
[0009] Exemplarily, the cross-sectional shape of the airflow channel is: cross-shaped, T-shaped, straight-shaped, or fan-shaped.
[0010] Exemplarily, a cavity is formed on the back plate, and part of the diaphragm is located between the cavity and the air flow channel.
[0011] According to another aspect of the present application, a method for preparing an airflow sensor is provided, the method comprising: providing a microsensor and an integrated circuit chip, the microsensor comprising a substrate, a backplate formed on the substrate, a diaphragm formed on the backplate, and a sacrificial layer formed on the diaphragm; forming an airflow channel penetrating the sacrificial layer on the sacrificial layer; forming a first groove on the substrate and the backplate, and forming a second groove on the sacrificial layer, wherein a portion of the diaphragm is located between the first groove and the second groove, and wherein the airflow channel and the second groove are connected; bonding the microsensor and the integrated circuit chip to form an integrated module; packaging the integrated module by a packaging component, wherein the integrated circuit chip is stacked on the sacrificial layer.
[0012] Exemplarily, the packaging component includes a substrate and a shell arranged on the substrate, and packaging the integrated module through the packaging component includes: thinning the substrate and the integrated circuit chip; fixing the substrate and the shell on the substrate, wherein a housing space is formed between the shell and the substrate, and the integrated module is located in the housing space.
[0013] Exemplarily, a first air hole and a second air hole are respectively provided on the housing and the substrate, and the second air hole is communicated with the first groove.
[0014] Exemplarily, packaging the integrated module by a packaging component further includes connecting the substrate and the integrated circuit chip by leads to establish an electrical connection between the integrated module and the packaging component; or connecting the substrate and the microsensor by solder balls to establish an electrical connection between the substrate and the integrated module.
[0015] Exemplarily, the air flow channel passes through at least two sides of the sacrificial layer, and a portion of the surface of the diaphragm contacts the air flow channel.
[0016] Exemplarily, the cross-sectional shape of the airflow channel is: cross-shaped, T-shaped, straight-shaped, or fan-shaped.
[0017] Exemplarily, the method further includes: forming a cavity on the back plate, and forming the diaphragm on the back plate so that part of the diaphragm is located between the cavity and the air flow channel.
[0018] Exemplarily, bonding the microsensor and the integrated circuit chip to form an integrated module includes: chemically mechanically polishing the surfaces of the microsensor and the integrated circuit chip; connecting the microsensor and the integrated circuit chip by bonding; and annealing the bonded microsensor and the integrated circuit chip to obtain the integrated module.
[0019] According to another aspect of the present application, an electronic device is provided, on which the above-mentioned airflow sensor is disposed.
[0020] An airflow sensor of the present application is formed with a back plate, a diaphragm and a sacrificial layer on a substrate, and a through airflow channel is opened on the sacrificial layer. The structure of the airflow channel can be used for the circulation of airflow, and the microsensor and the integrated circuit chip are integrated together by bonding and packaged. Compared with separate packaging, the occupied area can be reduced, and the overall size of the sensor is reduced. The airflow sensor of the present application, on the one hand, can reduce the occupied area to reduce the size by stacking the microsensor and the integrated circuit chip, and on the other hand, it can facilitate the flow of airflow by opening a breathable airflow channel on the sacrificial layer to avoid opening holes on the integrated circuit chip, thereby ensuring the integrity and stability of the dedicated integrated circuit, and also reducing the difficulty of preparation. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] By describing the embodiments of the present application in more detail in conjunction with the accompanying drawings, the above and other purposes, features and advantages of the present application will become more apparent. The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application. In the accompanying drawings, the same reference numerals generally represent the same components or steps.
[0022] Figure 1 The figure shows a schematic diagram of the structure of an airflow sensor in the related art.
[0023] Figure 2 A schematic diagram of the structure of a stack of MEMS components and ASIC components in the related art is shown.
[0024] Figure 3 A schematic diagram showing the structure of the stacking of ASIC components and MEMS components in the related art
[0025] Figure 4 A cross-sectional schematic diagram of the airflow sensor structure in the first embodiment of the present application is shown.
[0026] Figure 5 A cross-sectional schematic diagram of a cross-shaped airflow channel in the present application is shown.
[0027] Figure 6(a)-Figure 6(c) Schematic cross-sectional views of other shapes of air flow channels in the present application are shown.
[0028] Figure 7 A flow chart of a method for preparing an airflow sensor in Embodiment 2 of the present application is shown.
[0029] Figure 8 A flow chart of the steps for forming a sacrificial layer air flow channel in the present application is shown.
[0030] Fig. 9 A flow chart of the bonding and packaging steps in this application is shown. DETAILED DESCRIPTION
[0031] In order to make the purpose, technical solutions and advantages of the present application more obvious, the example embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application, and it should be understood that the present application is not limited to the example embodiments described herein. Based on the embodiments of the present application described in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present application.
[0032] like Figure 1 As shown, it is a structural schematic diagram of an airflow sensor in the related art, and the airflow sensor includes a MEMS component 104, an ASIC component 105, a PCB board 107 and a packaging shell 103. The MEMS component 104 is responsible for converting the air pressure signal into an electrical signal, and the ASIC component 105 is responsible for analyzing, processing, amplifying and transmitting the electrical signal converted by the MEMS. A lead 106 is connected between the MEMS component 104 and the ASIC component 105, and a lead 106 is also connected between the ASIC component 105 and the PCB board 107. The electrical connection is achieved through the lead 106 to transmit the signal. When the airflow sensor is working, the airflow enters from the air inlet 101, and the air pressure acts on the diaphragm on the MEMS component 104, causing the diaphragm to vibrate, causing the charge amount of the parallel plate capacitor formed between the diaphragm and the back plate to change, generating an electrical signal, and the electrical signal is transmitted to the ASIC component through the lead 106 for analysis and processing, while the airflow flows out from the air leakage hole 102.
[0033] In the above-mentioned airflow sensor, the MEMS component and the ASIC component are packaged separately, each of which occupies an area of a PCB board, which increases the size of the airflow sensor and thus increases the cost.
[0034] In order to solve the problem of large size, the related technology will adopt the method of stacking MEMS components and ASIC components, such as Figure 2 and Figure 3 As shown in FIG. 1 , a schematic diagram of another airflow sensor in the related art is shown. The ASIC component and the MEMS component are stacked together, and then the stacked ASIC component and the MEMS component are fixed on a PCB board, and an electrical connection is established with the PCB board through leads. The ASIC component can be located below the MEMS component (e.g. Figure 2 ), or can be stacked on top of a MEMS component (as shown in Figure 3 As shown in the figure, no matter which stacking method is used, holes need to be opened on the ASIC component to facilitate the airflow in the sensor. This method has high requirements for ASIC components and PCB boards, is more difficult to process, and will also increase production costs and affect the integrity and stability of the ASIC components.
[0035] Embodiment 1
[0036] like Figure 4 As shown, an embodiment of the present application provides an airflow sensor. The airflow sensor includes a microsensor (such as a MEMS component) and an integrated circuit chip 405 (such as an ASIC component). The microsensor includes a substrate 401, a back plate 402 formed on the substrate 401, a diaphragm 403 formed on the back plate 402, and a sacrificial layer 404 formed on the diaphragm 403, wherein an airflow channel 406 penetrating the sacrificial layer 404 is formed on the sacrificial layer 404; a first groove 407 is formed on the substrate 401 and the back plate 402, a second groove 408 is provided on the sacrificial layer 404, and a portion of the diaphragm 403 is located between the first groove 407 and the second groove 408.
[0037] The integrated circuit chip 405 and the micro sensor are bonded to form an integrated module, wherein the integrated circuit chip 405 is stacked on the sacrificial layer 404, and the integrated module is packaged by a packaging component.
[0038] The airflow sensor of the embodiment of the present application is provided with a through airflow channel 406 on the sacrificial layer 404. The structure of the airflow channel 406 can be used for the circulation of airflow. The microsensor and the integrated circuit chip 405 are integrated together by bonding and packaged. Compared with separate packaging, the occupied area can be reduced, and the overall size of the sensor is reduced. The airflow sensor of the present application, on the one hand, can reduce the occupied area to reduce the size by stacking the microsensor and the integrated circuit chip 405. On the other hand, a breathable airflow channel 406 can be provided on the sacrificial layer 404 to avoid opening holes on the integrated circuit chip 405, thereby ensuring the integrity and stability of the integrated circuit chip 405, and also reducing the cost and difficulty of preparation.
[0039] Exemplarily, the sacrificial layer 404 is formed on the diaphragm 403, and the sacrificial layer 404 is an oxide layer. The substrate 401 may be a silicon substrate. When the back plate 402 is formed on the substrate 401, a thin oxide layer is first formed on the substrate 401 by oxidation, and then silicon nitride, polysilicon and silicon nitride are deposited in sequence to form the back plate 402 structure. The diaphragm 403 includes polysilicon, and the diaphragm 403 is formed by depositing polysilicon on the back plate 402. Finally, an oxide layer is continuously deposited on the diaphragm 403 to form the sacrificial layer 404.
[0040] Exemplarily, the gas flow channel 406 on the sacrificial layer 404 is formed by etching, such as by a wet etching process or a dry etching process to form the gas flow channel 406. The dry etching process includes, but is not limited to, reactive ion etching (RIE), ion beam etching, plasma etching or laser cutting. The source gas of the dry etching may include CF4, CHF3 or other fluorocarbon gases. As an example, in the present embodiment, the etching is dry etching, and the process parameters of the dry etching include: the etching gas includes CF4, CHF3 and other gases, and the flow rates thereof are 50 sccm to 500 sccm and 10 sccm to 100 sccm, respectively, and the pressure is 2 mTorr to 50 mTorr, wherein sccm represents cubic centimeters per minute, and mTorr represents millimeters of mercury.
[0041] The airflow channel 406 on the sacrificial layer 404 penetrates at least two sides of the sacrificial layer 404, and a portion of the surface of the diaphragm 403 contacts the airflow channel 406 to facilitate the flow of air. In addition, the airflow channel 406 is connected to the second groove 408. Figure 5 As shown, the cross-section of the airflow channel 406 on the sacrificial layer 404 can be a cross-shaped, and the airflow channel 406 connects the four sides of the sacrificial layer 404. After the sensor is packaged, the cross-shaped airflow channel 406 can achieve better airflow. In addition, the airflow channel 406 on the sacrificial layer 404 can also be other shapes. As shown in FIG6(a), the cross-section of the airflow channel 406 can be T-shaped, and the airflow channel 406 runs through the three sides of the sacrificial layer 404. As shown in FIG6(b), the cross-section of the airflow channel 406 can be a straight line shape, and the airflow channel 406 runs through the two sides of the sacrificial layer 404. As shown in FIG6(c), the cross-section of the airflow channel 406 can be a fan ring, and the airflow channel 406 runs through the two sides of the sacrificial layer 404.
[0042] A first groove 407 and a second groove 408 are formed on the micro sensor, wherein the first groove 407 is formed by etching the substrate 401 and the back plate 402, and the second groove 408 is formed by etching the sacrificial layer 404. After the first groove 407 and the second groove 408 are formed, the diaphragm 403 is partially located between the first groove 407 and the second groove 408. When the airflow enters the first groove 407 through the airflow channel 406, it acts on the diaphragm 403, causing the diaphragm 403 to vibrate, causing the charge amount of the parallel plate capacitor formed between the diaphragm 403 and the back plate 402 to change, generating an electrical signal, which is transmitted to the integrated circuit chip 405 for analysis and processing. One of the at least two side surfaces through which the airflow channel 406 on the sacrificial layer 404 passes is a side close to the first groove 407, ensuring that the airflow can flow fully without opening a hole on the integrated circuit chip 405.
[0043] After the microsensor and the integrated circuit chip 405 are bonded to be integrated together, they are packaged together. Compared with packaging alone, less area can be occupied, and the size after packaging can be controlled to be smaller, so that more dies (bare crystals) can be drawn in the unit wafer, thereby saving costs. In addition, the two are directly bonded, so there is no need to use leads to achieve electrical connection between the two, thereby reducing signal transmission loss and related external factors. Interference and influence. Exemplarily, when the microsensor and the integrated circuit chip 405 are bonded to form an integrated module, the surfaces of the microsensor and the integrated circuit chip 405 are first polished and polished, and the microsensor and the integrated circuit chip 405 are connected by bonding. The bonded microsensor and the integrated circuit chip 405 are annealed to obtain an integrated module. Among them, for the process of polishing and polishing, a conventional flattening method in the field of semiconductor manufacturing can be used to achieve surface flattening. Non-limiting examples of the flattening method include a mechanical flattening method and a chemical mechanical polishing (CMP) flattening method. In some embodiments, a more commonly used chemical mechanical polishing flattening method is used for polishing and polishing.
[0044] Exemplarily, the packaging assembly includes a substrate 410 and a housing 411 disposed on the substrate 410. When the integrated microsensor and the integrated circuit chip 405 are packaged, the substrate 401 and the integrated circuit chip 405 are thinned; the substrate 401 and the housing 411 are fixed on the substrate 410, wherein the integrated module is located between the housing 411 and the substrate 410, and a receiving space is formed between the housing 411 and the substrate 410, and the integrated module is located in the receiving space. Before packaging, the substrate 401 and the integrated circuit chip 405 are thinned according to the size obtained according to actual needs, so that the size meets the packaging requirements. Exemplarily, after thinning, etching, chrome gold, lead connection, release and other processes are required, and finally the substrate 401 on the integrated module is fixed on the substrate 410. Exemplarily, the substrate 410 is a PCB board, and the fixing method between the integrated module and the substrate 410 is welding. After the fixing of the integrated module is completed, the housing 411 is fixed on the substrate 410, and the packaging of the integrated module is completed. The housing 411 of the package assembly is made of metal. The substrate 410 and the integrated circuit chip 405 are electrically connected via leads, or the substrate 410 and the microsensor are electrically connected via solder balls 409 (eg, Figure 4 As shown). By way of example, the solder ball 409 is a tin ball.
[0045] Exemplarily, a first air hole 412 is provided on the housing 411, and a second air hole 413 is provided on the substrate 410. The second air hole 413 is located below the integrated circuit chip 405, and the second air hole 413 is connected to the first groove 407. The airflow enters the package assembly through the first air hole 412, and then is discharged to the outside of the package assembly through the airflow channel 406 on the sacrificial layer 404 and the second air hole 413 on the substrate 410. Alternatively, the airflow can enter the package assembly through the second air hole 413, and then be discharged through the first air hole 412. Through the first air hole 412, the second air hole 413 and the airflow channel 406 on the sacrificial layer 404, the airflow can flow so that the airflow sensor can work smoothly.
[0046] Exemplarily, when the airflow passes through the airflow channel 406, in order to better cause the vibration of the diaphragm 403, a cavity (not shown in the figure) can be formed on the back plate 402, and the diaphragm 403 is partially located between the cavity and the airflow channel 406. When the airflow passes through the airflow channel 406, the diaphragm 403 can be caused to vibrate, thereby generating an electrical signal. Exemplarily, when forming the cavity, firstly, a groove is made on the back plate 402 and filled with a sacrificial material that can be corroded, and then the diaphragm 403 is formed on the back plate 402 by deposition or the like, and finally the filled sacrificial material is removed by etching or the like to obtain the cavity on the back plate 402. Through the structure of the cavity, the diaphragm 403 will be more sensitive to the airflow, and the capacitance can be changed when the airflow passes through, thereby generating an electrical signal.
[0047] An airflow sensor provided in an embodiment of the present application has a sacrificial layer 404 formed on a substrate 401, and a through airflow channel 406 is provided on the sacrificial layer 404. The structure of the airflow channel 406 can be used for the circulation of airflow. The microsensor and the integrated circuit chip 405 are integrated together by bonding and packaged. Compared with separate packaging, the occupied area can be reduced and the overall size of the sensor can be reduced. On the other hand, by providing a breathable airflow channel 406 on the sacrificial layer 404 to avoid opening holes on the integrated circuit chip 405, the integrity and stability of the integrated circuit chip 405 are ensured, and the difficulty of preparation is also reduced.
[0048] like Figure 7 As shown, the embodiment of the present application provides a method for preparing an airflow sensor, comprising the following steps:
[0049] S710, providing a micro sensor and an integrated circuit chip, wherein the micro sensor includes a substrate, a back plate formed on the substrate, a diaphragm formed on the back plate, and a sacrificial layer formed on the diaphragm.
[0050] S720, forming an air flow channel penetrating the sacrificial layer on the sacrificial layer.
[0051] S730, forming a first groove on the substrate and the back plate, and forming a second groove on the sacrificial layer, wherein a portion of the diaphragm is located between the first groove and the second groove.
[0052] S740, bonding the micro sensor and the integrated circuit chip to form an integrated module.
[0053] S750, encapsulating the integrated module through a packaging component, wherein the integrated circuit chip is stacked on the sacrificial layer.
[0054] The present application provides a method for preparing an airflow sensor, wherein a back plate, a diaphragm and a sacrificial layer are formed on a substrate, and a through airflow channel is opened on the sacrificial layer. The structure of the airflow channel can be used for the circulation of airflow, and the microsensor and the integrated circuit chip are integrated together by bonding and packaged. Compared with separate packaging, the occupied area can be reduced, and the overall size of the sensor is reduced. The sensor prepared by this method can reduce the occupied area to reduce the size by stacking the microsensor and the integrated circuit chip, and on the other hand, a breathable airflow channel can be opened on the sacrificial layer to avoid opening holes on the integrated circuit chip, thereby ensuring the integrity and stability of the integrated circuit chip, and also reducing the difficulty of preparation.
[0055] like Figure 8As shown, it is a cross-sectional schematic diagram of the device in the step of forming the airflow channel of the sacrificial layer in the embodiment of the present application. Exemplarily, the sacrificial layer is formed on the diaphragm, and the sacrificial layer is an oxide layer. The substrate can be a silicon substrate. When forming a back plate on the substrate, a portion of a thinner oxide layer is first formed on the substrate by oxidation, and then silicon nitride, polysilicon and silicon nitride are deposited in sequence to form a back plate structure. The diaphragm includes polycrystalline silicon, and a diaphragm is formed by depositing polycrystalline silicon on the back plate. Finally, an oxide layer is continuously deposited on the diaphragm to form a sacrificial layer. An airflow channel is formed by corroding the inside of the sacrificial layer. It should be noted that the sacrificial layer, the substrate and the back plate need to be corroded to form a first groove and a second groove, and finally a MEMS finished product is formed.
[0056] Exemplarily, the airflow channel on the sacrificial layer is formed by etching, such as by a wet etching process or a dry etching process. The dry etching process includes, but is not limited to, reactive ion etching (RIE), ion beam etching, plasma etching or laser cutting. The source gas for dry etching may include CF4, CHF3 or other fluorocarbon gases. As an example, in the present embodiment, the etching is dry etching, and the process parameters of the dry etching include: the etching gas includes CF4, CHF3 and other gases, and the flow rates thereof are 50 sccm to 500 sccm, 10 sccm to 100 sccm, respectively, and the pressure is 2 mTorr to 50 mTorr, wherein sccm represents cubic centimeters per minute, and mTorr represents millimeters of mercury.
[0057] The airflow channel on the sacrificial layer runs through at least two sides of the sacrificial layer, and a portion of the surface of the diaphragm contacts the airflow channel to facilitate the flow of air. Figure 5 As shown, the cross-section of the airflow channel on the sacrificial layer can be a cross-shaped one, and the airflow channel connects the four sides of the sacrificial layer. After the sensor is packaged, the cross-shaped airflow channel can achieve better airflow. In addition, the airflow channel on the sacrificial layer can also be other shapes. As shown in FIG6(a), the cross-section of the airflow channel can be T-shaped, and the airflow channel runs through the three sides of the sacrificial layer. As shown in FIG6(b), the cross-section of the airflow channel can be a straight line, and the airflow channel runs through the two sides of the sacrificial layer. As shown in FIG6(c), the cross-section of the airflow channel can be a fan-shaped one, and the airflow channel runs through the two sides of the sacrificial layer. Ensure that the airflow can flow fully so that there is no need to open holes on the integrated circuit chip.
[0058] Exemplarily, the first groove is formed by etching the substrate and the back plate, and the second groove is formed by etching the sacrificial layer. After the first groove and the second groove are formed, part of the diaphragm is located between the first groove and the second groove. When the airflow enters the first groove through the airflow channel, it acts on the diaphragm, causing the diaphragm to vibrate, causing the amount of charge of the parallel plate capacitor formed between the diaphragm and the back plate to change, generating an electrical signal, and the electrical signal is transmitted to the integrated circuit chip for analysis and processing. Exemplarily, the method also includes: forming a cavity on the back plate, forming a diaphragm on the back plate so that part of the diaphragm is located between the cavity and the airflow channel. When the airflow passes through the airflow channel, it can also cause the diaphragm to vibrate, thereby generating an electrical signal.
[0059] like Fig. 9 As shown, it is a cross-sectional view of the device in the bonding and packaging process in the embodiment of the present application. Exemplarily, the process of bonding the microsensor and the integrated circuit chip to form an integrated module includes: grinding and polishing the surface of the microsensor and the integrated circuit chip; connecting the microsensor and the integrated circuit chip by bonding; annealing the bonded microsensor and the integrated circuit chip to obtain an integrated module. Among them, for the grinding and polishing process, a conventional planarization method in the field of semiconductor manufacturing can be used to achieve surface planarization. Non-limiting examples of the planarization method include a mechanical planarization method and a chemical mechanical polishing (CMP) planarization method. In some embodiments, a more commonly used chemical mechanical polishing planarization method is used for grinding and polishing. After the microsensor and the integrated circuit chip are bonded together for integration, they are packaged together. Compared with packaging alone, less area can be occupied, and the size after packaging can be controlled to be smaller, so that more dies (bare crystals) can be drawn in the unit wafer, thereby saving costs. In addition, the two are directly bonded, so there is no need to use leads to achieve electrical connection between the two, thereby reducing signal transmission loss and related external factors. Interference and influence.
[0060] After the bonded integrated module is obtained, it is packaged through a packaging component. Exemplarily, the packaging component includes a substrate and a shell arranged on the substrate, and the packaging process includes: thinning the substrate and the integrated circuit chip; fixing the substrate and the shell on the substrate, wherein the integrated module is located between the shell and the substrate. Before packaging, the substrate and the integrated circuit chip are thinned according to the size obtained according to actual needs so that their size meets the packaging requirements. Exemplarily, after thinning, it is necessary to perform corrosion, chrome gold, lead connection, release and other processes, and finally fix the substrate on the integrated module on the substrate. Exemplarily, the substrate is a PCB board, and the fixing method between the integrated module and the substrate is welding. After the fixing of the integrated module is completed, the shell is fixed on the substrate, and the packaging of the integrated module is completed. A accommodating space is formed between the shell and the substrate, and the integrated module is located in the accommodating space. Among them, the shell of the packaging component is a metal material.
[0061] Exemplarily, a first air hole is provided on the housing, and a second air hole is provided on the substrate. The second air hole is located below the integrated circuit chip. The airflow enters the package assembly through the first air hole, and then enters the outside of the package assembly through the airflow channel on the sacrificial layer and the second air hole on the substrate. Alternatively, the airflow can enter the package assembly through the second air hole, and then be discharged through the first air hole. The airflow can flow through the first air hole, the second air hole, and the airflow channel on the sacrificial layer, so that the airflow sensor can work smoothly.
[0062] Exemplarily, packaging the integrated module by the packaging component further includes connecting the substrate and the integrated circuit chip by wires to establish an electrical connection between the integrated module and the packaging component (eg, Fig. 9 Alternatively, the substrate and the microsensor are connected by solder balls to establish an electrical connection between the substrate and the integrated module (as shown in FIG. Figure 4 As shown). Exemplarily, the solder ball is a tin ball.
[0063] That is, when packaging the integrated module, you can choose to achieve the connection between the integrated module and the substrate by means of leads or solder balls. When connecting through leads, the two ends of the leads are respectively connected to the integrated circuit chip and the substrate. When the connection between the integrated module and the substrate is achieved through solder balls, the solder balls connect the substrate and the substrate. Through the solder balls, the integrated circuit chip, the microsensor and the substrate are connected together to achieve electrical connection. The electrical connection through solder balls is a ball grid array (BGA) connection method. The solder balls are alloys composed of tin, silver, copper, etc. After using solder balls to replace leads, the integration is higher, and it has higher stability than leads. When the airflow passes through, it will not be hindered by the leads, which can reduce signal loss and improve sensitivity.
[0064] The present application provides a method for preparing an airflow sensor, wherein a back plate, a diaphragm and a sacrificial layer are formed on a substrate, and a through airflow channel is opened on the sacrificial layer. The structure of the airflow channel can be used for the circulation of airflow, and the microsensor and the integrated circuit chip are integrated together by bonding and packaged. Compared with separate packaging, the occupied area can be reduced, and the overall size of the sensor is reduced. The sensor prepared by this method can reduce the occupied area to reduce the size by stacking the microsensor and the integrated circuit chip, and on the other hand, a breathable airflow channel can be opened on the sacrificial layer to avoid opening holes on the integrated circuit chip, thereby ensuring the integrity and stability of the integrated circuit chip, and also reducing the difficulty of preparation.
[0065] Embodiment 3
[0066] The embodiment of the present application provides an electronic device, on which the airflow sensor as described above is arranged. Exemplarily, the electronic device may be an electronic smoking device.
[0067] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application to this. Those of ordinary skill in the art may make various changes and modifications therein without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as required by the appended claims.
[0068] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.
[0069] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed.
[0070] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.
[0071] Similarly, it should be understood that in order to streamline the present application and help understand one or more of the various inventive aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present application should not be interpreted as reflecting the following intention: the claimed application requires more features than the features clearly stated in each claim. More specifically, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with features less than all the features of a single disclosed embodiment. Therefore, the claims following the specific embodiment are hereby explicitly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present application.
[0072] It will be understood by those skilled in the art that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.
[0073] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims, any one of the claimed embodiments may be used in any combination.
[0074] The various component embodiments of the present application can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It should be understood by those skilled in the art that a microprocessor or a digital signal processor (DSP) can be used in practice to implement some or all of the functions of some modules according to the embodiments of the present application. The present application can also be implemented as a vehicle-mounted system program (e.g., a computer program and a computer program product) for executing part or all of the methods described herein. Such a program implementing the present application can be stored on a computer-readable medium, or can have the form of one or more signals. Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.
[0075] It should be noted that the above embodiments illustrate the present application rather than limit the present application, and that those skilled in the art may design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets should not be constructed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of multiple such elements. The present application may be implemented with the aid of hardware including several different elements and with the aid of appropriately programmed computers. In a unit claim listing several on-board systems, several of these on-board systems may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names.
[0076] The above is only a specific implementation method or description of a specific implementation method of the present application, and 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. The protection scope of the present application shall be based on the protection scope of the claims.
Claims
1. An airflow sensor, characterized in that: The air flow sensor comprises: A microsensor, the microsensor comprising a substrate, a back plate formed on the substrate, a diaphragm formed on the back plate, and a sacrificial layer formed on the diaphragm, wherein an air flow channel penetrating the sacrificial layer is formed on the sacrificial layer; a first groove is formed on the substrate and the back plate, a second groove is formed on the sacrificial layer, and a portion of the diaphragm is located between the first groove and the second groove; An integrated circuit chip, wherein the integrated circuit chip and the microsensor are bonded to form an integrated module, wherein the integrated circuit chip is stacked on the sacrificial layer; Packaging component, the integrated module is packaged by the packaging component.
2. The airflow sensor according to claim 1, characterized in that: The packaging component includes a substrate and a shell arranged on the substrate, the substrate and the shell are fixed on the substrate, a receiving space is formed between the shell and the substrate, and the integrated module is located in the receiving space.
3. The airflow sensor according to claim 2, characterized in that: The housing and the substrate are respectively provided with a first air hole and a second air hole, and the second air hole is communicated with the first groove.
4. The airflow sensor according to claim 2, characterized in that: The substrate and the integrated circuit chip are electrically connected via leads, or, The substrate and the micro sensor are electrically connected via solder balls.
5. The airflow sensor according to claim 1, characterized in that: The air flow channel passes through at least two sides of the sacrificial layer, and a portion of the surface of the diaphragm contacts the air flow channel.
6. The airflow sensor according to claim 1, characterized in that: The cross-sectional shape of the airflow channel is: cross-shaped, T-shaped, straight-shaped, or fan-shaped.
7. The airflow sensor according to any one of claims 1 to 6, characterized in that: A cavity is formed on the back plate, and a portion of the diaphragm is located between the cavity and the air flow channel.
8. A method for preparing an airflow sensor, characterized in that: The method comprises: A micro sensor and an integrated circuit chip are provided, wherein the micro sensor comprises a substrate, a back plate formed on the substrate, a diaphragm formed on the back plate, and a sacrificial layer formed on the diaphragm; forming an air flow channel on the sacrificial layer that penetrates the sacrificial layer; forming a first groove on the substrate and the back plate, and forming a second groove on the sacrificial layer, wherein the portion of the diaphragm is located between the first groove and the second groove, and wherein the air flow channel is connected to the second groove; Bonding the microsensor and the integrated circuit chip to form an integrated module; The integrated module is packaged by a packaging assembly, wherein the integrated circuit chip is stacked on the sacrificial layer.
9. The method according to claim 8, characterized in that The packaging component includes a substrate and a housing disposed on the substrate, and packaging the integrated module by the packaging component includes: Thinning the substrate and the integrated circuit chip; The substrate and the shell are fixed on the base plate, wherein a receiving space is formed between the shell and the base plate, and the integrated module is located in the receiving space.
10. The method according to claim 9, characterized in that The housing and the substrate are respectively provided with a first air hole and a second air hole, and the second air hole is communicated with the first groove.
11. The method according to claim 9, characterized in that The packaging of the integrated module by a packaging component further includes: Connecting the substrate and the integrated circuit chip via leads to establish an electrical connection between the integrated module and the packaging component; or, The substrate and the micro sensor are connected via solder balls to establish electrical connection between the substrate and the integrated module.
12. The method according to claim 8, characterized in that The air flow channel passes through at least two sides of the sacrificial layer, and a portion of the surface of the diaphragm contacts the air flow channel.
13. The method according to claim 8, characterized in that The cross-sectional shape of the airflow channel is: cross-shaped, T-shaped, straight-shaped, or fan-shaped.
14. The method according to any one of claims 8 to 13, characterized in that: The method further includes: forming a cavity on the back plate, and forming the diaphragm on the back plate so that a portion of the diaphragm is located between the cavity and the air flow channel.
15. The method according to any one of claims 8 to 13, characterized in that: The step of bonding the micro sensor and the integrated circuit chip to form an integrated module comprises: Performing chemical mechanical polishing on the surfaces of the microsensor and the integrated circuit chip; Connecting the micro sensor and the integrated circuit chip by bonding; The bonded microsensor and the integrated circuit chip are annealed to obtain the integrated module.
16. An electronic device, characterized in that: The electronic device is provided with an airflow sensor as described in any one of claims 1-7.