Microphone and electronic device

Abstract

The application provides a microphone and an electronic device, and relates to the technical field of acoustic devices. The microphone comprises a circuit board and a cover shell arranged on the circuit board to form a containing space on the circuit board. A support structure and a MEMS chip are arranged in the containing space. The MEMS chip receives external sound signals through a sound hole arranged on the circuit board and an airflow channel formed by a breathable area of the support structure. The support structure comprises a lower silicon support layer, a lower oxide layer, a silicon-based material grid layer, an upper oxide layer, a silicon bonding layer and an upper silicon support layer arranged in sequence on the circuit board. The lower silicon support layer, the lower oxide layer and the upper oxide layer are hollow in the breathable area. The silicon-based material grid layer is provided with breathable holes in part of the array in the breathable area. The upper silicon support layer forms stepped holes connected by first through holes and second through holes in part of the breathable area. The microphone can effectively improve the key performance indicators, and meets the dustproof and waterproof requirements in harsh environments or extreme conditions.

Description

Technical Field

[0001] This application relates to the field of acoustic device technology, and more specifically, to a microphone and electronic device. Background Technology

[0002] MEMS microphones are microphones manufactured based on MEMS (Micro-Electro-Mechanical Systems) technology. They typically utilize a capacitive sound sensor formed by a charged backplane and a thin film. The vibration of the flexible diaphragm is proportional to the amplitude and frequency of the sound wave, and the resulting voltage change is measured, processed, and output by integrated analog or digital dedicated circuitry. These microphones are widely used as important sound transmission elements in various electronic devices, such as mobile phones and computers, as sound receiving components.

[0003] The performance of an acoustic sensor is determined by a series of key indicators. These indicators also directly affect the applicability of the acoustic sensor in different device scenarios. Among them, high signal-to-noise ratio (SNR) and maximum sound pressure level (high AOP) are the core indicators.

[0004] As a MEMS microphone used in electronic devices, it is essential to prevent liquids, dust, or other small particles from entering and negatively impacting its sound pickup performance while ensuring clear and stable sound reception. Current technologies employ various solutions, such as installing mesh filters on the PCB board corresponding to the sound holes to isolate liquids and dust and protect the internal structure. However, filters located on the outside of the PCB are easily damaged by environmental factors, while filters located on the inside of the PCB involve complex manufacturing processes and exhibit poor consistency between batches. Other solutions integrate the filter structure within the MEMS microphone structure; however, the size of such filters is limited by the size of the MEMS microphone itself, hindering improvements in the microphone's signal-to-noise ratio. Utility Model Content

[0005] This application provides a microphone and electronic device that can effectively improve the key performance indicators of the microphone, while also meeting the requirements for dustproof and waterproofing in harsh environments or extreme conditions.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows: In one aspect of this application, a microphone is provided, including a circuit board and a cover on the circuit board to form an accommodating space on the circuit board. A support structure and a MEMS chip are disposed in the accommodating space. The MEMS chip receives external sound signals through sound holes opened on the circuit board and airflow channels formed by the venting area on the support structure. The support structure includes a lower silicon support layer, a lower oxide layer, a silicon-based material grid layer, an upper oxide layer, a silicon bonding layer, and an upper silicon support layer arranged sequentially on the circuit board. The portions of the lower silicon support layer, the lower oxide layer, and the upper oxide layer located in the venting area are all hollowed out. The portion of the silicon-based material grid layer located in the venting area is provided with an array of venting holes. The portion of the upper silicon support layer located in the venting area forms a stepped hole formed by a first through hole and a second through hole. The second through hole is located on the side of the upper silicon support layer near the silicon-based material grid layer, and the diameter of the first through hole is smaller than the diameter of the second through hole. The silicon bonding layer conformally covers the surface of the upper silicon support layer on the side near the silicon-based material grid layer.

[0007] In some feasible implementations, the silicon-based material grid layer is made of silicon or silicon nitride.

[0008] In some feasible implementations, the silicon-based material mesh layer includes a mesh structure layer with air pores arrayed in the air-permeable region, and also includes a hydrophobic layer disposed on the surface of the mesh structure layer.

[0009] In some feasible implementations, the pore diameter of the vent is less than or equal to 3 μm, and the opening area of ​​the vent within the vent region is greater than or equal to 1 / 2 of the total area of ​​the silicon-based material mesh layer.

[0010] In some feasible implementations, the second through-hole of the upper silicon support layer coincides with the projection of the ventilated area of ​​the silicon-based material grid layer and together define the airflow channel of the support structure.

[0011] In some feasible implementations, the minimum width of the support portion of the lower silicon substrate located outside the airflow channel is greater than or equal to 180 micrometers.

[0012] In some feasible implementations, a flow-blocking block is also provided in the hollow area of ​​the lower silicon support layer so that the sound signal flowing into the airflow channel through the sound hole of the circuit board changes the airflow direction through the flow-blocking block.

[0013] In some feasible implementations, the projection of the choke block on the circuit board at least covers a portion of the acoustic aperture.

[0014] In some feasible implementations, the current blocking blocks include multiple blocks, which are spaced apart; the distance between adjacent current blocking blocks, and / or the distance between the current blocking blocks and the cutout edge of the lower silicon substrate is greater than or equal to 0.1 mm.

[0015] In some feasible implementations, the microphone of this application embodiment further includes an ASIC chip disposed within an accommodating space and connected to the circuit board for signal transmission, wherein the ASIC chip is fixedly disposed on the circuit board, or the ASIC chip is fixedly disposed on the upper silicon substrate.

[0016] Another aspect of this application provides a method for fabricating a microphone, including providing an upper silicon substrate and etching a second via on the upper silicon substrate; providing a lower silicon substrate and forming a lower oxide layer and a silicon-based material mesh layer on the lower silicon substrate, etching the silicon-based material mesh layer to form an array of vent holes in a portion of the venting region, and forming an upper oxide layer on the silicon-based material mesh layer; conformally depositing a silicon bonding layer on one side of the upper silicon substrate where the second via is formed; bonding the silicon bonding layer on the upper silicon substrate to the upper oxide layer on the lower silicon substrate; etching a first via in the upper silicon substrate and the silicon bonding layer to form a stepped via communicating with the second via, wherein the diameter of the first via is smaller than that of the second via. The aperture of the two vias is etched, and the upper silicon substrate after etching forms the upper silicon substrate layer; the lower silicon substrate is etched to form a cutout in the venting area, and the etched lower silicon substrate forms the lower silicon substrate layer; the lower oxide layer and the upper oxide layer located in the venting area are removed to form a support structure; the support structure is fixed on the circuit board, and the venting area of ​​the support structure corresponds to the acoustic hole on the circuit board; a MEMS chip is attached to the support structure, and the MEMS chip receives external sound signals through the acoustic hole opened on the circuit board and the airflow channel formed by the venting area on the support structure; a cover is placed on the circuit board to cover the support structure and the MEMS chip in the accommodating space formed by the circuit board and the cover.

[0017] In some feasible implementations, a silicon bonding layer is conformally deposited on the side of the upper silicon substrate where the second via is formed, and the bonding of the silicon bonding layer on the upper silicon substrate to the upper oxide layer on the lower silicon substrate is performed in the same bonding apparatus.

[0018] In some feasible implementations, etching the lower silicon substrate to form a cutout in the venting region includes: etching the lower silicon substrate in the venting region; and stopping the etching at the lower oxide layer.

[0019] In some feasible implementations, etching the lower silicon substrate to form a cutout in the ventilated area includes: patterning the lower silicon substrate in the ventilated area using photolithography, retaining an island structure of the lower silicon substrate in the cutout of the ventilated area as a flow barrier, the projection of the flow barrier on the circuit board at least covering a portion of the acoustic hole, and the sound signal flowing into the airflow channel through the acoustic hole of the circuit board changing the airflow direction through the flow barrier.

[0020] In some feasible implementations, before etching the first via in the upper silicon substrate and silicon bonding layer to form a stepped via communicating with the second via, the method further includes thinning the upper silicon substrate.

[0021] In some feasible implementations, before etching the lower silicon substrate to form a cutout in the venting region, the method further includes: bonding temporary bonding glass on the upper silicon substrate; and thinning the lower silicon substrate.

[0022] In another aspect of the embodiments of this application, an electronic device is provided, including the microphone of any of the foregoing.

[0023] The beneficial effects of the embodiments of this application include: The microphone provided in the embodiments of this application has a support structure made by MEMS technology, which includes a lower silicon support layer, a lower oxide layer, a silicon-based material grid layer, an upper oxide layer, a silicon bonding layer and an upper silicon support layer arranged sequentially on the circuit board. The portions of the lower silicon support layer, the lower oxide layer and the upper oxide layer located in the ventilated area are all hollowed out. The portion of the silicon-based material grid layer located in the ventilated area is provided with an array of ventilated holes. The portion of the upper silicon support layer located in the ventilated area forms a stepped hole formed by the connection of a first through hole and a second through hole. The second through hole is located on the side of the upper silicon support layer close to the silicon-based material grid layer, and the diameter of the first through hole is smaller than the diameter of the second through hole. The silicon bonding layer conformally covers the surface of the upper silicon support layer on the side close to the silicon-based material grid layer. The support structure fabricated using MEMS technology ensures excellent consistency across different processing batches. The bonding process between the upper and lower silicon support layers utilizes a conformally conformally overlaid silicon bonding layer on the surface of a silicon-based material grid. This reduces the warpage requirements of the bonded upper and lower silicon support layers, allowing for high-quality bonding even with some degree of warpage. Furthermore, by using a support structure fabricated with MEMS technology to support the MEMS chip on the circuit board, the effective area of ​​the venting region can be increased while maintaining support stability, thereby improving the signal-to-noise ratio. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is one of the structural schematic diagrams of a microphone provided in an embodiment of this application; Figure 2 One of the schematic diagrams of a microphone support structure provided in an embodiment of this application; Figure 3 A partially enlarged view of a microphone support structure provided in an embodiment of this application; Figure 4A schematic diagram of a silicon-based material grid layer in a microphone support structure provided in an embodiment of this application; Figure 5 A second schematic diagram of a microphone support structure provided in an embodiment of this application; Figure 6 This is a second schematic diagram of the structure of a microphone provided in an embodiment of this application; Figure 7 This is the third schematic diagram of the structure of a microphone provided in the embodiments of this application; Figure 8 This is the fourth schematic diagram of a microphone structure provided in the embodiments of this application; Figure 9 A flowchart illustrating a method for manufacturing a microphone, as provided in an embodiment of this application; Figure 10 This is one of the schematic diagrams illustrating the steps of a microphone manufacturing method provided in an embodiment of this application; Figure 11 This is a second schematic diagram illustrating the steps of a microphone manufacturing method provided in this application embodiment; Figure 12 This is the third schematic diagram illustrating the steps of a microphone manufacturing method according to an embodiment of this application; Figure 13 The fourth schematic diagram illustrates the steps of a microphone manufacturing method provided in this application embodiment; Figure 14 The fifth schematic diagram illustrates the steps of a microphone manufacturing method provided in this application embodiment; Figure 15 This is the sixth schematic diagram of a microphone manufacturing method provided in this application embodiment.

[0026] Icons: 110 - Circuit board; 111 - Acoustic hole; 120 - Support structure; 121 - Lower silicon support layer; 1210 - Flow choke; 122 - Lower oxide layer; 123 - Silicon-based material mesh layer; 1230 - Mesh structure layer; 1231 - Vent hole; 1232 - Hydrophobic layer; 124 - Upper oxide layer; 125 - Upper silicon support layer; 1251 - First through hole; 1252 - Second through hole; 126 - Silicon bonding layer; 130 - MEMS chip; 200 - Housing; 300 - ASIC chip; AA - Vent area. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. It should be noted that, in the absence of conflict, the various features in the embodiments of this application can be combined with each other, and the combined embodiments are still within the protection scope of this application.

[0028] In the description of this application, it should be noted that the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and therefore should not be construed as limiting this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0029] Microphones are used in electronic devices, such as those in mobile phones. They need to ensure clear and stable sound signal reception while preventing dust, small particles, or moisture from entering the acoustic sensors and negatively impacting the microphone's sound pickup performance during use. Current technologies, whether using traditional external waterproof mesh or a combination of internal waterproof mesh and steel plates, suffer from complex processes, inconsistent quality, and susceptibility to damage, affecting their lifespan.

[0030] Based on this, one aspect of the embodiments of this application provides a microphone, such as... Figure 1 As shown, the device includes a circuit board 110 and a cover 200 covering the circuit board 110 to form an accommodating space. A support structure 120 and a MEMS chip 130 are disposed within the accommodating space. The MEMS chip 130 receives external sound signals through an airflow channel formed by a sound hole 111 on the circuit board 110 and a ventilated area AA on the support structure 120. Please refer to... Figure 2As shown, the support structure 120 includes a lower silicon support layer 121, a lower oxide layer 122, a silicon-based material mesh layer 123, an upper oxide layer 124, a silicon bonding layer 126, and an upper silicon support layer 125 sequentially disposed on the circuit board 110. The portions of the lower silicon support layer 121, lower oxide layer 122, and upper oxide layer 124 located in the ventilated area AA are all perforated. The portion of the silicon-based material mesh layer 123 located in the ventilated area AA has arrayed vent holes 1231. The portion of the upper silicon support layer 125 located in the ventilated area AA forms a stepped hole formed by connecting a first through hole 1251 and a second through hole 1252. The second through hole 1252 is located on the side of the upper silicon support layer 125 near the silicon-based material mesh layer 123, and the diameter of the first through hole 1251 is smaller than the diameter of the second through hole 1252. The silicon bonding layer 126 conformally covers the surface of the upper silicon support layer 125 near the silicon-based material mesh layer 123.

[0031] like Figure 1 As shown, the MEMS chip 130 is mounted on the circuit board 110 via a support structure 120 and covered by a cover 200. Within the accommodating space formed by the circuit board 110 and the cover 200, the MEMS chip 130 is isolated from the external environment, preventing the microphone from being impacted or affected by dust, other small particles, and moisture. The MEMS chip 130 smoothly receives external sound signals through the airflow channel formed by the sound hole 111 on the circuit board 110 and the vent area AA on the support structure 120. The received external sound signals enter the MEMS chip 130 with almost no loss, realizing the acoustic performance of the sound sensor.

[0032] MEMS chip 130 is mounted on circuit board 110 via support structure 120. For example... Figure 2 As shown, the support structure 120 includes a lower silicon support layer 121 that is attached to the circuit board 110, and a lower oxide layer 122, a silicon-based material mesh layer 123, an upper oxide layer 124, a silicon bonding layer 126, and an upper silicon support layer 125 sequentially formed on the lower silicon support layer 121. In the venting region AA, the lower silicon support layer 121, lower oxide layer 122, and upper oxide layer 124 are hollowed out. The silicon-based material mesh layer 123 forms an array of vent holes 1231 in the venting region AA. The upper silicon support layer 125 forms stepped holes in the venting region AA, conformally covering the silicon bonding layer 126 on the upper silicon support layer 125 where the second through-hole 1252 has been formed. The portion located in the stepped hole is simultaneously etched away. The stepped hole is formed by connecting the second through-hole 1252 on the side near the silicon-based material mesh layer 123 and the second through-hole 1252 on the outer side. (Refer to...) Figure 2As indicated by the double-headed arrow, the diameter of the first through-hole 1251 is smaller than that of the second through-hole 1252. External airflow enters through the acoustic aperture 111 of the circuit board 110, flows into the MEMS chip 130 through the airflow channel formed by the ventilated area AA of the support structure 120, and is generated as a sound signal. The structure of the lower silicon support layer 121 and the upper silicon support layer 125 ensures stable support and fixation for the MEMS chip 130. The bonding process between the lower silicon support layer 121 and the upper silicon support layer 125 is performed through the silicon bonding layer 126, further ensuring the bonding stability between the two layers. Moreover, the bonding process reduces the requirements for the warpage of the lower and upper silicon support layers 121 and 125, improving the bonding yield. The hollowed-out lower silicon support layer 121 and the stepped holes in the upper silicon support layer 125 ensure smooth airflow and improve acoustic performance. The silicon-based material grid layer 123 can be made of silicon or silicon nitride material. The thickness of the silicon-based material grid layer 123 is less than or equal to 3 micrometers. It can have both dustproof and waterproof functions. The air vents 1231 arranged in the array in the air-permeable area AA allow airflow.

[0033] It should be noted that in the microphone of this embodiment, the lower silicon support layer 121 and the upper silicon support layer 125 are bonded and fixed together by a bonding process. A silicon bonding layer 126 is pre-conformally covered on one side of the upper silicon support layer 125 where the second through-hole 1252 has been formed. Using the silicon bonding layer 126 for the bonding process between the lower and upper silicon support layers 121 and 125 reduces the warpage requirement for the lower and upper silicon support layers 121 and 125, allowing for a high-quality bonding effect even when there is a certain degree of warpage during the process. Furthermore, the total thickness of the support structure 120 is controlled within a size range of less than or equal to 180 micrometers to avoid the support structure 120 being too thick and affecting the microphone's acoustic performance. It also increases the effective area of ​​the ventilation region while ensuring support stability, thereby improving the signal-to-noise ratio.

[0034] The microphone provided in this embodiment includes a circuit board 110 and a cover 200 covering the circuit board 110 to form an accommodating space. A support structure 120 and a MEMS chip 130 are disposed within the accommodating space. The MEMS chip 130 receives external sound signals through an airflow channel formed by a sound hole 111 on the circuit board 110 and a venting area AA on the support structure 120. The cover 200 and the circuit board 110 protect the MEMS chip 130 within the accommodating space from contact with external dust and moisture. The support structure fabricated using MEMS technology includes a lower silicon support layer 121, a lower oxide layer 122, a silicon-based material grid layer 123, an upper oxide layer 124, a silicon bonding layer 126, and an upper silicon support layer 125 sequentially arranged on a bonding circuit board 110. The portions of the lower silicon support layer 121, the lower oxide layer 122, and the upper oxide layer 124 located in the ventilated area AA are all hollowed out. The portion of the silicon-based material grid layer 123 located in the ventilated area AA is provided with an array of ventilating holes 1231. The portion of the upper silicon support layer 125 located in the ventilated area AA forms a stepped hole formed by connecting a first through hole 1251 and a second through hole 1252. The second through hole 1252 is located on the side of the upper silicon support layer 125 near the silicon-based material grid layer 123, and the diameter of the first through hole 1251 is smaller than the diameter of the second through hole 1252. The silicon bonding layer 126 conformally covers the surface of the upper silicon support layer 125 near the silicon-based material grid layer 123. The support structure 120, fabricated using MEMS technology, ensures good consistency across different processing batches. The bonding process between the upper and lower silicon support layers 121 utilizes a conformally conformally covering the silicon bonding layer 126 on the surface of the upper silicon support layer 125, where the second via 1252 is formed. This reduces the warpage requirements for the bonded upper and lower silicon support layers 125 and 121, allowing for high-quality bonding even with some degree of warpage. Furthermore, by using the support structure 120 to support the MEMS chip 130 on the circuit board 110, the effective area of ​​the ventilation region AA can be increased while maintaining support stability, thus improving the signal-to-noise ratio.

[0035] In some feasible implementations, the silicon-based material grid layer 123 is made of silicon or silicon nitride.

[0036] The silicon-based material grid layer 123 is made of silicon or silicon nitride, which effectively ensures the dustproof and waterproof performance of the silicon-based material grid layer 123 and provides sufficient support strength.

[0037] In some feasible implementations, such as Figure 3 As shown, the silicon-based material grid layer 123 includes a grid structure layer 1230 with ventilating holes 1231 arranged in the ventilating region AA array, and also includes a hydrophobic layer 1232 disposed on the surface of the grid structure layer 1230.

[0038] like Figure 3 As shown, the silicon-based material mesh layer 123 includes a two-layer structure. A hydrophobic layer 1232 is disposed on the mesh structure layer 1230. The hydrophobic layer 1232 is a coating or material with low surface energy, which can repel water and prevent liquid from penetrating into the mesh structure layer 1230 through the hydrophobic layer 1232, protecting the mesh structure layer 1230 from structural damage such as water erosion and oxidation. Moreover, the surface of the hydrophobic layer 1232 can reduce the adhesion of water, and the process of water sliding off the surface of the hydrophobic layer 1232 can also remove surface dirt, keeping the surface of the silicon-based material mesh layer 123 clean. For example, the hydrophobic angle of the hydrophobic layer 1232 is greater than or equal to 105° to ensure the protection of the mesh structure layer 1230 by the hydrophobic layer 1232.

[0039] It should be noted that the arrangement of the hydrophobic layer 1232 within the mesh structure layer 1230 is not specifically limited in this embodiment. For example, the hydrophobic layer 1232 can be arranged as follows: Figure 3 As shown, it can cover the entire surface of the mesh structure layer 1230, or it can be set only on one side of the mesh structure layer 1230, for example, on the side of the mesh structure layer 1230 facing the circuit board 110, so as to block water from entering the external airflow.

[0040] In some feasible implementations, such as Figure 4 As shown, the pore size of the vent 1231 in the silicon-based material grid layer 123 is less than or equal to 3μm, and the opening area of ​​the vent 1231 in the vent region AA is greater than or equal to 1 / 2 of the total area of ​​the silicon-based material grid layer 123.

[0041] like Figure 4 As shown, taking the ventilation holes 1231 in the ventilation area AA of the silicon-based material mesh layer 123 as an example, the diameter of the ventilation holes 1231 is less than or equal to 3μm to avoid affecting the dustproof and water-proof capabilities of the silicon-based material mesh layer 123 due to excessively large diameters. Furthermore, the total opening area of ​​all ventilation holes 1231 within the ventilation area AA is greater than or equal to half the total area of ​​the silicon-based material mesh layer 123. This maximizes the opening area of ​​the ventilation holes 1231 on the silicon-based material mesh layer 123 while ensuring structural support strength, thereby increasing the effective area of ​​the ventilation area and improving the signal-to-noise ratio while maintaining support stability.

[0042] In some feasible implementations, refer to Figure 2 As shown, the projection of the second through hole 1252 of the upper silicon support layer 125 coincides with the projection of the permeable area AA of the silicon-based material grid layer 123 and together they define the airflow channel of the support structure 120.

[0043] like Figure 2As shown, the airflow channel of the support structure 120 is used for airflow entering through the acoustic holes 111 of the circuit board 110. The size of the openings in each layer of the support structure 120 is jointly determined, and the opening of any layer will affect the overall airflow direction. Therefore, the projection of the second through hole 1252 of the upper silicon support layer 125 coincides with the projection of the ventilated area AA of the silicon-based material grid layer 123, and matches the cutout of the lower silicon support layer 121. If there is a portion where the projection of the second through hole 1252 of the upper silicon support layer 125 intersects with the projection of the ventilated area AA of the silicon-based material grid layer 123, the intersecting portion is not considered part of the ventilated area AA of the support structure 120.

[0044] In some feasible implementations, the minimum width of the support portion of the lower silicon support layer 121 located outside the airflow channel is greater than or equal to 180 micrometers.

[0045] Still refer to Figure 2 The lower silicon support layer 121 has a permeable area AA cut out to serve as an airflow channel. The support portion outside the airflow channel needs to support the MEMS chip 130 it carries. Therefore, the minimum width of the support portion of the lower silicon support layer 121 is greater than or equal to 180 micrometers to ensure stable support for each position of the MEMS chip 130.

[0046] In some feasible implementations, such as Figure 5 As shown, a flow-blocking block 1210 is also provided in the hollow area of ​​the lower silicon support layer 121 so that the sound signal flowing into the airflow channel through the sound hole 111 of the circuit board 110 changes the airflow direction through the flow-blocking block 1210.

[0047] like Figure 5 As shown, a flow-blocking block 1210 is also provided in the hollow area of ​​the lower silicon support layer 121. The flow-blocking block 1210 divides the breathable area AA of the lower silicon support layer 121 into multiple small channels.

[0048] Please refer to again Figure 6 As shown, the MEMS chip 130 is mounted on the circuit board 110 via a support structure 120 and is located within the accommodating space of the circuit board 110 and the housing 200. The MEMS chip 130 receives external sound signals through the airflow channel formed by the sound hole 111 on the circuit board 110 and the venting area AA on the support structure 120. When a flow-blocking block 1210 is also provided in the hollowed-out area of ​​the silicon substrate 121, such as... Figure 6 As shown by the red arrow, the airflow entering through the sound hole 111 impacts the baffle block 1210 and changes its direction. The airflow then enters the MEMS chip 130 through the airflow channel from the edge of the baffle block 1210 to receive the sound signal. By changing the direction of the airflow impact through the baffle block 1210, the microphone of this embodiment can improve its ability to resist airflow impact.

[0049] Since the baffle 1210 is positioned in the hollowed-out area to change the direction of airflow entering through the sound hole 111, thereby improving the microphone's resistance to airflow, in some feasible implementations, the baffle 1210 needs to be positioned so that its projection on the circuit board 110 at least covers a portion of the sound hole 111. This is necessary to change and adjust the airflow direction entering through the sound hole 111.

[0050] Of course, based on the above examples illustrating the placement of the flow obstruction block 1210, as well as the explanation of the purpose and expected effect of the flow obstruction block 1210, those skilled in the art can, according to the core ideas of the above design scheme of the embodiments of this application, and based on the actual microphone usage scenario and the characteristics of airflow in the actual scenario, make specific settings for the placement position, shape and quantity of the flow obstruction block 1210. The embodiments of this application do not make specific limitations in this regard.

[0051] For example, in some feasible embodiments, the flow obstruction block 1210 includes a plurality of flow obstruction blocks 1210, which are spaced apart. That is, the flow obstruction blocks 1210 and the flow obstruction block 1210 and the inner edge of the cutout can serve as airflow channels. The distance between adjacent flow obstruction blocks 1210, and / or the distance between the flow obstruction block 1210 and the inner edge of the cutout of the lower silicon substrate 121 is greater than or equal to 0.1 mm, to ensure smooth airflow in the airflow channels.

[0052] In some feasible implementations, such as Figure 7 As shown, the microphone in this embodiment of the application also includes an ASIC chip 300 disposed within the accommodating space and signal-connected to the circuit board 110, wherein the ASIC chip 300 is fixedly disposed on the circuit board 110, or, as shown... Figure 8 As shown, the ASIC chip 300 is fixedly mounted on the upper silicon substrate 125.

[0053] When the microphone in this embodiment of the application also includes an ASIC chip 300 disposed in the accommodating space and connected to the circuit board 110 via a signal, the ASIC chip 300 can be as follows: Figure 7 As shown, it is installed on circuit board 110, or as... Figure 8 As shown, the ASIC chip 300 is disposed on the upper silicon support layer 125, that is, the ASIC chip 300 is also supported by the support structure 120.

[0054] It should be noted that, as Figure 8 As shown, when the ASIC chip 300 is also supported by the support structure 120, the support structure 120 can set the range of the ventilation area AA as large as possible while ensuring stable support for the ASIC chip 300 and the MEMS chip 130, so as to improve the acoustic performance of the microphone.

[0055] Another aspect of the embodiments of this application provides a method for manufacturing a microphone, such as... Figure 9 As shown, the method includes: S101, such as Figure 10 As shown, an upper silicon substrate is first provided, and a second via 1252 is etched on the upper silicon substrate.

[0056] S102, such as Figure 11 As shown, a lower silicon substrate is provided, on which a lower oxide layer 122 and a silicon-based material grid layer 123 are sequentially formed. The silicon-based material grid layer 123 is etched to form an array of vent holes 1231 in a portion of the vent region AA. An upper oxide layer 124 is formed on the silicon-based material grid layer 123 on which the array of vent holes 1231 are formed.

[0057] S103, such as Figure 12 As shown, a silicon bonding layer 126 is conformally deposited on the side of the upper silicon substrate where the second via 1252 is formed.

[0058] like Figure 12 As shown, in the previous step, a second via 1252 is formed on the upper silicon substrate. A silicon bonding layer 126 is conformally deposited on one side of the second via 1252. The silicon bonding layer 126 covers the surface of the upper silicon substrate on the side where the second via 1252 is formed, and also covers the inner wall and bottom wall of the second via 1252.

[0059] S104, still refer to Figure 12 As shown, the silicon bonding layer 126 on the upper silicon substrate and the upper oxide layer 124 on the lower silicon substrate are bonded together. Specifically, during the bonding of the upper and lower silicon substrates, the silicon bonding layer 126 is used to bond them together. This method reduces the requirements for wafer warpage during the bonding process. In other words, even if there is a certain degree of warpage between the upper and lower silicon substrates in the previous process, the silicon bonding layer 126, as the bonding connection layer, can effectively reduce the requirements for wafer warpage and improve the bonding yield.

[0060] S105, such as Figure 13 As shown, a first via 1251 is etched in the upper silicon substrate and the silicon bonding layer 126 to form a stepped via that communicates with a second via 1252. The diameter of the first via 1251 is smaller than the diameter of the second via 1252. After the stepped via is etched in the upper silicon substrate, the upper silicon substrate is formed as the upper silicon substrate layer 125.

[0061] from Figure 13As can be seen, during the etching process to form the first via 1251, a portion of the silicon bonding layer 126 located on the bottom wall of the first via 1251 is also removed simultaneously, thereby forming the first via 1251 to the stepped via 1252 that communicates with the second via 1252.

[0062] S106, such as Figure 15 As shown, the lower silicon substrate is etched to form a cutout in the venting region AA. After the cutout is formed on the lower silicon substrate, the lower silicon substrate is formed as the lower silicon substrate layer 121.

[0063] S107, such as Figure 2 As shown, the lower oxide layer 122 and the upper oxide layer 124 located in the breathable area AA are removed to form a support structure 120.

[0064] S108, such as Figure 1 As shown, the support structure 120 is fixedly mounted on the circuit board 110, and the ventilation area AA of the support structure 120 corresponds to the sound hole 111 on the circuit board 110.

[0065] S109, still refer to Figure 1 As shown, a MEMS chip 130 is fixedly mounted on the support structure 120. The MEMS chip 130 receives external sound signals through the airflow channel formed by the sound hole 111 on the circuit board 110 and the air-permeable area AA on the support structure 120. A cover 200 is placed on the circuit board 110, covering the support structure 120 and the MEMS chip 130 within the accommodating space formed by the circuit board 110 and the cover 200.

[0066] In some feasible embodiments, the preparation of steps S103 and S104 can be carried out using the same bonding equipment, so that the two steps are completed continuously in the same bonding equipment. For example, in step S103, the upper silicon substrate is placed in the bonding equipment, and a silicon bonding layer 126 is conformally deposited on one side of the second via 1252 of the upper silicon substrate. The silicon bonding layer 126 covers the surface of the upper silicon substrate on the side where the second via 1252 is formed, as well as the inner wall and bottom wall of the second via 1252. After depositing the silicon bonding layer 126, step S104 is continued, and the upper silicon substrate and the lower silicon substrate are bonded together in the bonding equipment. Specifically, the silicon bonding layer 126 side on the upper silicon substrate is aligned and bonded to the upper oxide layer 124 side on the lower silicon substrate. In this way, while using silicon bonding layer 126 to reduce the requirements of the bonding process on wafer warpage, the complexity of the process will not be increased, and the process difficulty or yield will not be reduced by adding process steps.

[0067] In some feasible embodiments, etching the lower silicon substrate to form a cutout in the venting region AA includes: etching the lower silicon substrate in the venting region AA, with the etching stopping at the lower oxide layer 122.

[0068] When etching the silicon substrate in the venting region AA, the lower oxide layer 122 acts as an etching stop layer, which can protect the silicon-based material grid layer 123, especially the vent holes 1231 of the array that have been etched, during the etching process. This prevents the structure of the vent holes 1231 from being damaged due to over-etching or poor control of etching parameters during the etching of the silicon substrate, thus avoiding damage to the microphone structure.

[0069] Similarly, the upper oxide layer 124 can also protect the silicon-based material grid layer 123 and the vent 1231 during bonding and etching, thus ensuring that the structural size and spacing of the vent 1231 will not affect the setting of the silicon-based material grid layer 123. This protects the silicon-based material grid layer 123 during the fabrication process and ensures the acoustic performance of the microphone after fabrication.

[0070] In some feasible implementations, for example, in the microphone of this embodiment, a flow-blocking block 1210 is formed in the hollow of the lower silicon substrate 121 to improve the anti-blowing ability during use. In its fabrication process, the step of etching the lower silicon substrate to form a hollow in the ventilated area AA further includes: patterning the lower silicon substrate in the ventilated area AA by photolithography. This allows the island structure of the lower silicon substrate 121 to be retained in the hollow of the ventilated area AA as the flow-blocking block 1210. The projection of the flow-blocking block 1210 on the circuit board 110 at least covers a part of the sound hole 111. The sound signal flowing into the airflow channel through the sound hole 111 of the circuit board 110 changes the airflow direction through the flow-blocking block 1210.

[0071] Using this method, when a microphone needs to be fabricated with flow-blocking blocks 1210 formed in the hollows of the lower silicon substrate 121 to improve the microphone's anti-blow-out capability during use, there is no need to add complex fabrication processes. Instead, during the step of etching the lower silicon substrate to form hollows in the permeable area AA, patterned photolithography can be used to retain island structures as flow-blocking blocks 1210 at predetermined positions in the hollows within a single etching step using a mask. Moreover, when multiple flow-blocking blocks 1210 with different parameters are required, the corresponding parameter requirements can be met simply by designing the corresponding pattern on the mask in advance, without adding extra fabrication processes. This avoids the problems of increased processing costs and decreased yield caused by process complexity.

[0072] In some feasible embodiments, before etching the first via 1251 in the upper silicon substrate and the silicon bonding layer to form a stepped via communicating with the second via 1252, the method further includes: like Figure 12and 13 As shown, a thinning process is performed on the upper silicon substrate, and the thinning stops when the upper silicon substrate reaches the preset thickness.

[0073] In some feasible implementations, before etching the lower silicon substrate to form a cutout in the vent region AA, the method further includes: Temporary bonded glass is bonded to the upper silicon support layer 125, which already has stepped holes. For example... Figure 14 As shown, the temporary bonding glass ensures that the support structure 120 has sufficient support strength for thinning the lower silicon substrate and for the process of hollowing out the lower silicon substrate to form the lower silicon support layer 121. While ensuring that the support structure 120 has sufficient support strength, the lower silicon support substrate is thinned to a predetermined thickness.

[0074] In another aspect of the embodiments of this application, an electronic device is provided, including the microphone of any of the foregoing.

[0075] When the microphone of this application embodiment is applied to various electronic devices, including consumer electronic devices or medical testing instruments, as long as the microphone provided in this application embodiment is installed in the corresponding electronic device and connected to the controller of the electronic device, the microphone of this application embodiment has better acoustic performance, meets various extreme working environments, and can effectively prevent small particles such as dust and moisture from entering the microphone and affecting its working performance, thereby improving the microphone's sensitivity and stability in electronic devices. This also allows the electronic device of this application embodiment to be more widely used in various working environments.

[0076] In this application, the electronic device may be a driving device that can be electronically controlled, such as a car, ship, or aircraft; a single-function electronic device such as a rangefinder; a customized electronic device with multiple functions such as a robot; or other forms or types of electronic devices. In this application, the type of electronic device is not specifically limited.

[0077] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A microphone, characterized in that, The device includes a circuit board and a cover on the circuit board to form an accommodating space on the circuit board. A support structure and a MEMS chip are disposed in the accommodating space. The MEMS chip receives external sound signals through the sound holes opened on the circuit board and the airflow channel formed by the ventilated area on the support structure. The support structure includes a lower silicon support layer, a lower oxide layer, a silicon-based material mesh layer, an upper oxide layer, a silicon bonding layer, and an upper silicon support layer arranged sequentially on the circuit board. The portions of the lower silicon support layer, the lower oxide layer, and the upper oxide layer located in the ventilated area are all hollowed out. The portion of the silicon-based material mesh layer located in the ventilated area is provided with an array of ventilating holes. The portion of the upper silicon support layer located in the ventilated area forms a stepped hole formed by a first through hole and a second through hole. The second through hole is located on the side of the upper silicon support layer near the silicon-based material mesh layer, and the diameter of the first through hole is smaller than the diameter of the second through hole. The silicon bonding layer conformally covers the surface of the upper silicon support layer on the side near the silicon-based material mesh layer.

2. The microphone according to claim 1, characterized in that, The silicon-based material grid layer is made of silicon or silicon nitride.

3. The microphone according to claim 1, characterized in that, The silicon-based material mesh layer includes a mesh structure layer with air pores arrayed in the air-permeable region, and also includes a hydrophobic layer disposed on the surface of the mesh structure layer.

4. The microphone according to any one of claims 1-3, characterized in that, The pore diameter of the vent is less than or equal to 3 μm, and the opening area of ​​the vent within the vent region is greater than or equal to 1 / 2 of the total area of ​​the silicon-based material mesh layer.

5. The microphone according to any one of claims 1-3, characterized in that, The second through-hole of the upper silicon support layer coincides with the projection of the air-permeable area of ​​the silicon-based material grid layer and together define the airflow channel of the support structure.

6. The microphone according to any one of claims 1-3, characterized in that, The minimum width of the supporting portion of the lower silicon support layer located outside the airflow channel is greater than or equal to 180 micrometers.

7. The microphone according to any one of claims 1-3, characterized in that, A flow-blocking block is also provided in the hollow area of ​​the lower silicon support layer so that the sound signal flowing into the airflow channel through the sound hole of the circuit board changes the airflow direction through the flow-blocking block.

8. The microphone according to claim 7, characterized in that, The projection of the flow-blocking block on the circuit board at least covers a portion of the acoustic hole.

9. The microphone according to claim 7, characterized in that, The flow-blocking blocks include multiple blocks, which are spaced apart; the distance between adjacent flow-blocking blocks, and / or the distance between the flow-blocking blocks and the cutout edge of the lower silicon substrate is greater than or equal to 0.1 mm.

10. The microphone according to claim 1, characterized in that, It also includes an ASIC chip disposed within the accommodating space and connected to the circuit board via signals, wherein the ASIC chip is fixedly disposed on the circuit board, or the ASIC chip is fixedly disposed on the upper silicon substrate.

11. An electronic device, characterized in that, Includes the microphone as described in any one of claims 1-10.

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