MEMS packaging structure and method for preparing the same

Abstract

The embodiment of the present invention provides a MEMS packaging structure and a method for preparing the MEMS packaging structure, which relates to the field of semiconductor packaging technology. The MEMS packaging structure includes a substrate, an ASIC chip, a MEMS chip and a sound inlet cover. The sound inlet cover includes an inner cover and an outer cover that are integrally arranged. The inner cover has a first cavity, and the outer cover has a second cavity. The first cavity and the second cavity are interconnected, thereby forming a front sound cavity, increasing the volume of the sound inlet space, and improving the sound pressure / sound signal, thereby improving the sensitivity and signal-to-noise ratio of the chip. At the same time, the sound is input through multiple sound inlet holes, which avoids the chip from directly contacting the external sound pressure / sound. Therefore, when the sound pressure / sound changes beyond a certain value, the first cavity and the second cavity can play a buffering role, avoiding the rupture of the silicon diaphragm caused by high-intensity sound pressure / sound impact, which greatly improves the applicability of the MEMS chip.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor packaging technology, and in particular to a MEMS packaging structure and a method for preparing the MEMS packaging structure. Background Art

[0002] With the rapid development of the semiconductor industry, microphones have been widely used in various electronic products in the consumer field. Among them, silicon microphones have been widely used in mobile terminals due to their small size and strong stability. Silicon microphones include MEMS (Micro Electro Mechanical System) chips, and MEMS chips include silicon diaphragms and silicon back plates. Among them, the working principle of the MEMS chip is to use the pressure gradient generated by sound changes to cause the silicon diaphragm to deform due to sound pressure / sound interference, thereby changing the capacitance value between the silicon diaphragm and the silicon back plate, thereby converting the sound pressure / sound signal into a voltage signal. The existing MEMS silicon microphone product design allows sound to directly enter the MEMS chip and the metal cover from a single hole / single direction. When the sound signal is very weak, the sound pressure / sound signal is weaker, resulting in a decrease in the sensitivity and signal-to-noise ratio of the MEMS silicon microphone product. At the same time, the external sound pressure / sound of the existing MEMS silicon microphone product is in direct contact with the silicon diaphragm on the MEMS chip. Therefore, when the intensity of the sound pressure / sound change exceeds a certain value, the silicon diaphragm will break due to the high-intensity sound pressure / sound impact, resulting in poor applicability. Summary of the invention

[0003] The objectives of the present invention include, for example, providing a MEMS packaging structure and a method for preparing a MEMS packaging structure, which can increase the sound cavity space of the MEMS silicon diaphragm, thereby improving the signal-to-noise ratio and frequency response performance of the silicon microphone product, and improving its sensitivity. At the same time, when the sound pressure / sound change exceeds a certain value, it can play a buffering role to avoid high-intensity sound pressure / sound impact and cause the silicon diaphragm to rupture, thereby greatly improving the applicability of the MEMS chip.

[0004] The embodiments of the present invention can be implemented as follows:

[0005] In a first aspect, the present invention provides a MEMS packaging structure, comprising:

[0006] substrate;

[0007] An ASIC chip and a MEMS chip are arranged on the substrate at intervals;

[0008] A sound inlet cover body is arranged on the substrate, and the sound inlet cover body covers the outside of the ASIC chip and the MEMS chip;

[0009] Among them, the sound inlet cover body includes an inner cover body and an outer cover body which are integrally arranged, the inner cover body has a first cavity, the ASIC chip and the MEMS chip are both accommodated in the first cavity, the outer cover body spacer is arranged outside the inner cover body, and has a second cavity, the outer cover body is provided with a first sound inlet hole connected to the second cavity, the side of the inner cover body is provided with a second sound inlet hole, and the inner cover body also has a sound transmission channel, the sound transmission channel is connected to the second sound inlet hole, and the top wall of the first cavity is also provided with a first sound transmission hole, the first sound transmission hole is connected to the sound transmission channel.

[0010] In an optional embodiment, the outer cover body also has a third cavity, and a chamber partition is also provided in the outer cover body, and the chamber partition is used to divide the space between the inner cover body and the outer cover body into a second cavity and a third cavity, and a back sound hole is also provided on the substrate, and the MEMS chip cover is provided on the back sound hole, and the back sound hole is connected to the third cavity.

[0011] In an optional embodiment, a sound guide hole is also provided on the substrate, wherein the sound guide hole is located between the inner cover body and the outer cover body and is connected to the third cavity, and a sound guide channel is also provided in the substrate, wherein both ends of the sound guide channel extend to the sound guide hole and the back sound hole respectively, so as to connect the sound guide hole and the back sound hole.

[0012] In an optional embodiment, two sides of the chamber partition are respectively connected to the outer wall of the inner cover body and the inner wall of the outer cover body.

[0013] In an optional embodiment, a sound intake groove is further provided on the top of the outer cover body, and the sound intake groove is located between the second cavity and the third cavity, and the first sound intake hole is provided on the side wall of the sound intake groove that is connected to the second cavity, so that the first sound intake hole passes through to the second cavity.

[0014] In an optional embodiment, the chamber partition includes an integrally arranged first isolation portion and a second isolation portion, the first isolation portion is connected to the inner wall of the outer cover body, the second isolation portion is located between the inner cover body and the outer cover body and is connected to the substrate, the sound guide hole is located between the second isolation portion and the outer cover body, and a fourth cavity is also formed between the second isolation portion and the outer side wall of the inner cover body, and the fourth cavity is connected to the second cavity.

[0015] In an optional embodiment, a sound intake groove is further provided on the top of the outer cover body, and the sound intake groove is located between the second cavity and the third cavity. The first sound intake hole is provided on the side wall and bottom wall of the sound intake groove that are connected to the second cavity, so that the first sound intake hole passes through to the second cavity.

[0016] In an optional embodiment, the sound inlet groove passes through the inner cover body, and a bridging conductive shell is also provided in the sound inlet groove, the two ends of the bridging conductive shell are respectively connected to the second cavity and the fourth cavity, and a third sound inlet hole is provided on the bridging conductive shell to connect the sound inlet groove with the second cavity and the fourth cavity.

[0017] In an optional embodiment, the first isolation portion is joined to the side wall of the sound inlet groove combined with the second cavity, so that the periphery of the bridging conduction shell forms an annular channel, and a fourth sound inlet hole is also provided on the bridging conduction shell, and the fourth sound inlet hole is arranged opposite to the third sound inlet hole.

[0018] In an optional embodiment, a second sound transmission hole is provided on the side wall of the inner cover body combined with the fourth cavity, and the fourth cavity is connected to the first cavity through the second sound transmission hole.

[0019] In an optional embodiment, a waterproof membrane is further provided on the top side of the outer cover body, and the waterproof membrane covers the surface of the outer cover body.

[0020] In a second aspect, the present invention provides a method for preparing a MEMS packaging structure, which is used to prepare the MEMS packaging structure as described in any one of the above embodiments, and the preparation method comprises:

[0021] providing a substrate;

[0022] Mounting the ASIC chip and the MEMS chip on the substrate at intervals;

[0023] Mounting a sound inlet cover on the substrate, and placing the sound inlet cover outside the ASIC chip and the MEMS chip;

[0024] Among them, the sound inlet cover body includes an inner cover body and an outer cover body which are integrally arranged, the inner cover body has a first cavity, the ASIC chip and the MEMS chip are both accommodated in the first cavity, the outer cover body spacer is arranged outside the inner cover body, and has a second cavity, the outer cover body is provided with a first sound inlet hole connected to the second cavity, the side of the inner cover body is provided with a second sound inlet hole, and the inner cover body also has a sound transmission channel, the sound transmission channel is connected to the second sound inlet hole, and the top wall of the first cavity is also provided with a first sound transmission hole, the first sound transmission hole is connected to the sound transmission channel.

[0025] The beneficial effects of the embodiments of the present invention include, for example:

[0026] The present invention provides a MEMS packaging structure and a preparation method thereof, wherein a sound inlet cover body is provided on a substrate and covers the outside of an ASIC chip and a MEMS chip, and the inner cover body of the sound inlet cover body has a first cavity, the outer cover body has a second cavity, the outer cover body is provided with a first sound inlet hole, the side of the inner cover body is provided with a second sound inlet hole, and the first sound inlet hole and the second sound inlet hole are interconnected. The first cavity and the second cavity are interconnected, thereby forming a front sound cavity of the MEMS chip, increasing the volume of the sound inlet space, improving the sound pressure / sound signal, and thus improving the sensitivity and signal-to-noise ratio of the MEMS chip. At the same time, sound is introduced through multiple sound inlet holes, and the sound is introduced through the second cavity and the first cavity respectively, thereby avoiding direct contact between the MEMS chip and the external sound pressure / sound. Therefore, when the sound pressure / sound changes exceed a certain value, the first cavity and the second cavity can play a buffering role, avoiding the rupture of the silicon diaphragm caused by high-intensity sound pressure / sound impact, and greatly improving the applicability of the MEMS chip. Compared with the prior art, the MEMS packaging structure and preparation method provided by the present invention can increase the sound cavity space of the MEMS silicon diaphragm, thereby improving the signal-to-noise ratio and frequency response performance of the silicon microphone product and improving its sensitivity. At the same time, when the sound pressure / sound change exceeds a certain value, it can play a buffering role to avoid the rupture of the silicon diaphragm caused by high-intensity sound pressure / sound impact, thereby greatly improving the applicability of the MEMS chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A schematic cross-sectional view of a MEMS packaging structure provided by a first embodiment of the present invention;

[0029] Figure 2 A flowchart of a method for preparing a MEMS packaging structure according to a first embodiment of the present invention;

[0030] Figure 3 A schematic cross-sectional view of a MEMS packaging structure provided by a second embodiment of the present invention;

[0031] Figure 4 A schematic diagram of the appearance of a MEMS packaging structure provided by a second embodiment of the present invention;

[0032] Figure 5 A schematic cross-sectional view of a MEMS packaging structure provided by a third embodiment of the present invention;

[0033] Figure 6 A schematic cross-sectional view of a MEMS packaging structure provided by a fourth embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram of the appearance of a MEMS packaging structure provided by a fourth embodiment of the present invention.

[0035] Icon: 100-MEMS packaging structure; 110-substrate; 111-back sound hole; 112-sound guide hole; 113-sound guide channel; 120-ASIC chip; 130-MEMS chip; 140-sound inlet cover; 150-inner cover; 151-first cavity; 152-second sound inlet hole; 153-sound transmission channel; 154-first sound transmission hole; 155-second sound transmission hole; 160-outer cover; 161-second cavity; 162-first sound inlet hole; 163-third cavity; 164-sound inlet groove; 165-fourth cavity; 166-bridge conduction shell; 167-third sound inlet hole; 168-annular channel; 169-fourth sound inlet hole; 170-chamber partition; 171-first isolation part; 173-second isolation part; 180-waterproof membrane. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0039] In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0040] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0041] As disclosed in the background technology, the existing MEMS silicon microphone product is designed to allow sound to directly enter the MEMS chip and the metal cover from a single hole / single direction. When the sound signal is very weak, the sound pressure / sound signal becomes weaker, which leads to a decrease in the sensitivity and signal-to-noise ratio of the MEMS silicon microphone product. At the same time, the external sound pressure / sound of the existing MEMS silicon microphone product directly contacts the silicon diaphragm on the MEMS chip. Therefore, when the intensity of the sound pressure / sound change exceeds a certain value, the silicon diaphragm will break due to the high-intensity sound pressure / sound impact, resulting in poor applicability.

[0042] In addition, the sound inlet of the MEMS packaging structure in the prior art is usually directly opened on the surface of the cover plate and faces the external space. When mounting the cover plate, the suction nozzle is easy to contact with the sound inlet, resulting in foreign matter falling into the sound inlet when the suction nozzle surface is contaminated and picked up, causing foreign matter to appear in the cavity, affecting the performance of the sound cavity, and even causing the silicon diaphragm to vibrate and break, thereby affecting the product function.

[0043] In order to solve the above problems, the present invention provides a MEMS packaging structure and a method for preparing a MEMS packaging structure. It should be noted that, in the absence of conflict, the features in the embodiments of the present invention can be combined with each other, and the illustrations listed in the embodiments of the present invention are all cross-sectional illustrations, and their three-dimensional illustrations can be obtained by extending the cross-sectional illustrations front and back.

[0044] First embodiment

[0045] The present embodiment provides a MEMS packaging structure 100, which can increase the sound cavity space of the MEMS silicon diaphragm, thereby improving the signal-to-noise ratio and frequency response performance of the silicon microphone product, and improving its sensitivity. At the same time, when the sound pressure / sound change exceeds a certain value, it can play a buffering role to avoid high-intensity sound pressure / sound impact from causing the silicon diaphragm to rupture, thereby greatly improving the applicability of the MEMS chip 130.

[0046] The MEMS packaging structure 100 provided in this embodiment includes a substrate 110, an ASIC chip 120, a MEMS chip 130 and a sound inlet cover 140. The ASIC chip 120 and the MEMS chip 130 are spaced apart and attached to the substrate 110. The sound inlet cover 140 is arranged on the substrate 110 and covers the outside of the ASIC chip 120 and the MEMS chip 130, thereby realizing MEMS packaging.

[0047] In this embodiment, the sound inlet cover 140 includes an inner cover 150 and an outer cover 160 that are integrally arranged, the inner cover 150 has a first cavity 151, the ASIC chip 120 and the MEMS chip 130 are both accommodated in the first cavity 151, the outer cover 160 is spaced outside the inner cover 150, and has a second cavity 161, a first sound inlet hole 162 connected to the second cavity 161 is provided on the outer cover 160, a second sound inlet hole 152 is provided on the side of the inner cover 150, and the inner cover 150 also has a sound transmission channel 153, the sound transmission channel 153 is connected to the second sound inlet hole 152, and a first sound transmission hole 154 is also provided on the top wall of the first cavity 151, and the first sound transmission hole 154 is connected to the sound transmission channel 153.

[0048] It is worth noting that the ASIC chip 120 is electrically connected to the MEMS chip 130 and the substrate 110 by wire bonding. The ASIC chip 120 (ASIC, Application Specific Integrated Circuit) can be used as a control chip to control the MEMS chip 130. The specific control principle and working principle can refer to the existing MEMS packaging structure.

[0049] It should be noted that the surfaces of the inner cover 150 and the outer cover 160 are spaced apart and can be connected through the bottom surface or a local connection point. The inner cover 150 forms a first cavity 151, and the partial area between the outer surface of the inner cover 150 and the inner surface of the outer cover 160 forms a second cavity 161. When the sound is actually input, the sound pressure / sound can enter the second cavity 161 through the first sound input hole 162, and then enter the first cavity 151 through the second sound input hole 152 through the sound transmission channel 153 and the first sound transmission hole 154, and contact with the MEMS chip 130 to realize the transmission of sound pressure / sound. The first cavity 151 and the second cavity 161 are interconnected, thereby forming the front sound cavity of the MEMS chip 130, increasing the volume of the sound input space, improving the sound pressure / sound signal, and thus improving the sensitivity and signal-to-noise ratio of the MEMS chip 130. At the same time, sound is input through multiple first sound input holes 162, and sound is input through the second cavity 161 and the first cavity 151 respectively, thereby preventing the MEMS chip 130 from directly contacting external sound pressure / sound. Therefore, when the sound pressure / sound change exceeds a certain value, the first cavity 151 and the second cavity 161 can play a buffering role, preventing the silicon diaphragm from ruptured due to high-intensity sound pressure / sound impact, thereby greatly improving the applicability of the MEMS chip 130.

[0050] It should be noted that a first sound transmission hole 154 is provided on the inner cover body 150 where the top wall of the first cavity 151 is located. There can be multiple first sound transmission holes 154. Multiple first sound transmission holes 154 can divert sound pressure / sound, thereby improving the sensitivity, signal-to-noise ratio, and frequency response performance of the MEMS. At the same time, by designing a sound transmission channel 153, the sound transmission channel 153 is used to transmit the sound pressure / sound of the second sound inlet hole 152 on the side wall to the first sound transmission hole 154 at the bottom wall of the first cavity 151, thereby realizing the propagation of sound. Moreover, the sound transmission channel 153 here can be designed to be multiple, so that the sound pressure / sound propagation area can be increased through the sound transmission channel 153.

[0051] In this embodiment, the outer cover 160 also has a third cavity 163, and a chamber partition 170 is also provided in the outer cover 160. The chamber partition 170 is used to separate the space between the inner cover 150 and the outer cover 160 into a second cavity 161 and a third cavity 163. A back sound hole 111 is also provided on the substrate 110. The MEMS chip 130 is covered on the back sound hole 111, and the back sound hole 111 is connected to the third cavity 163. Specifically, in this embodiment, the chamber partition 170 is located in the middle of the outer cover 160, and evenly divides the space between the inner cover 150 and the outer cover 160 into the second cavity 161 and the third cavity 163. The specific separation method can be as follows: Figure 1In addition, in this embodiment, the chamber partition 170 is arranged in the vertical direction, and the two sides of the chamber partition 170 are respectively connected to the outer wall of the inner cover body 150 and the inner wall of the outer cover body 160, so as to ensure the separation effect.

[0052] In the present embodiment, a sound guide hole 112 is further provided on the substrate 110. The sound guide hole 112 is located between the inner cover body 150 and the outer cover body 160 and is connected to the third cavity 163. A sound guide channel 113 is also provided in the substrate 110. The two ends of the sound guide channel 113 extend to the sound guide hole 112 and the back sound hole 111 respectively, so that the sound guide hole 112 and the back sound hole 111 are connected. Specifically, the back sound hole 111 is connected to the bottom cavity of the MEMS chip 130, and is connected to the sound guide hole 112 through the sound guide channel 113, so that the bottom cavity of the MEMS chip 130 can be connected to the third cavity 163, wherein the third cavity 163 can serve as the back sound cavity of the MEMS chip 130, which increases the volume of the back sound cavity and increases the bottom sound cavity space of the MEMS silicon diaphragm, thereby improving the signal-to-noise ratio and frequency response performance of the silicon microphone product. At the same time, there may be multiple sound guide channels 113 distributed in the substrate 110, which can further increase the sound pressure / sound propagation area and improve the volume of the rear sound cavity.

[0053] It should be noted that, in the present embodiment, the second cavity 161 and the third cavity 163 divide the area between the inner cover body 150 and the outer cover body 160, which, on the one hand, increases the volume of the front sound cavity and the rear sound cavity respectively, thereby improving the signal-to-noise ratio and the frequency response performance; on the other hand, part of the second cavity 161 and the third cavity 163 are located above the sound transmission channel 153, so that the second cavity 161 and the third cavity 163 are concentrated inside the outer cover body 160, thereby reducing the volume of the outer cover body 160 and eliminating the need to separately arrange the second cavity 161 and the third cavity 163, which is conducive to the miniaturization of the product.

[0054] In this embodiment, the two sides of the chamber partition 170 are respectively connected to the outer wall of the inner cover 150 and the inner wall of the outer cover 160. Specifically, the chamber partition 170 is located in the middle of the outer cover 160, and can be joined with the inner cover 150 and the outer cover 160, and the joint is sealed to ensure that the second cavity 161 and the third cavity 163 are completely isolated.

[0055] In this embodiment, a sound inlet groove 164 is further provided at the top of the outer cover 160, and the sound inlet groove 164 is located between the second cavity 161 and the third cavity 163, and the first sound inlet hole 162 is provided on the side wall of the sound inlet groove 164 that is connected to the second cavity 161, so that the first sound inlet hole 162 passes through the second cavity 161. Specifically, the top of the outer cover 160 is recessed downward, that is, the sound inlet groove 164 is formed. It should be noted that the sound inlet groove 164 here can be formed by a stamping process, and the right side wall of the sound inlet groove 164 is connected to the second cavity 161, and the first sound inlet hole 162 is provided on the right side wall of the sound inlet groove 164. Of course, the first sound inlet hole 162 here can also be provided on other side walls of the sound inlet groove 164 that are connected to the second cavity 161.

[0056] It should be noted that the position of the cavity baffle here is adapted to the position of the sound inlet groove 164, so that the cavity baffle can constitute the left side wall of the sound inlet groove 164. Of course, in other preferred embodiments, the cavity baffle can also be arranged at intervals from the sound inlet groove 164. In addition, there can also be multiple first sound inlet holes 162 here, and multiple first sound inlet holes 162 are all arranged on the side wall, so as to increase the sound inlet area and ensure the sound inlet effect. At the same time, the first sound inlet hole 162 here adopts the side wall sound inlet, and the second sound inlet hole 152 also adopts the side wall sound inlet, and the first sound inlet hole 162 is located in the upper space of the second sound inlet hole 152, so that the sound pressure / sound will not directly enter the second sound inlet hole 152 from the first sound inlet hole 162, thereby avoiding the sound pressure / sound impact effect. At the same time, the first sound hole 154 is located at the top wall of the first cavity 151, and is not opposite to the second sound input hole 152, which further avoids the sound pressure / sound impact effect, can play a buffering role, and avoids the silicon diaphragm from breaking due to high-intensity sound pressure / sound impact, thereby greatly improving the applicability of the MEMS chip 130.

[0057] In this embodiment, a waterproof membrane 180 is further provided on the top side of the outer cover 160, and the waterproof membrane 180 covers the surface of the outer cover 160. Specifically, the waterproof membrane 180 is attached to the top side surface of the outer cover 160, and a vacuum coating method or mounting technology can be used when attaching the waterproof membrane 180. Since a sound inlet groove 164 is provided here, and the first sound inlet hole 162 is provided on the side wall of the sound inlet groove 164, even after the waterproof membrane 180 is attached here, the first sound inlet hole 162 will not be completely covered and blocked. The waterproof membrane 180 here can play a waterproof role, preventing external water vapor from directly entering the sound inlet groove 164 and entering the second cavity 161 through the first sound inlet hole 162. It should be noted that the waterproof membrane 180 here is a vibration membrane, which can well transmit sound pressure / sound, and a small pressure diffusion cavity can be formed at the sound inlet groove 164, which can send the sound pressure / sound into the first sound inlet hole 162 after converging.

[0058] See also Figure 2 This embodiment also provides a method for preparing a MEMS packaging structure, which is used to prepare the aforementioned MEMS packaging structure 100. The method comprises the following steps:

[0059] S1: Provide a substrate 110.

[0060] Specifically, the substrate 110 can be prepared in advance, and the sound guide hole 112, the back sound hole 111 and the sound guide channel 113 can be prepared in advance on the substrate 110, wherein the back sound hole 111 is located in the mounting area of ​​the MEMS chip 130, and the sound guide hole 112 is located in the mounting area of ​​the sound inlet cover 140.

[0061] S2: The ASIC chip 120 and the MEMS chip 130 are mounted on the substrate 110 at intervals.

[0062] Specifically, the ASIC chip 120 and the MEMS chip 130 are mounted on the substrate 110 using a conventional chip mounting process, and then wire bonding is completed so that the ASIC chip 120, the MEMS chip 130 and the substrate 110 can be electrically connected.

[0063] S3: Mount the sound inlet cover 140 on the substrate 110 .

[0064] Specifically, the sound inlet cover 140 is covered outside the ASIC chip 120 and the MEMS chip 130, and the pre-prepared sound inlet cover 140 is mounted on the substrate 110 through a bonding or welding process, wherein the sound inlet cover 140 needs to correspond to the position of the sound guide hole 112 and completely cover the outside of the ASIC chip 120 and the MEMS chip 130.

[0065] The sound inlet cover 140 includes an inner cover 150 and an outer cover 160 which are integrally arranged. The inner cover 150 has a first cavity 151. After the mounting is completed, the ASIC chip 120 and the MEMS chip 130 are both accommodated in the first cavity 151. The outer cover 160 is spaced outside the inner cover 150 and has a second cavity 161. A first sound inlet hole 162 communicating with the second cavity 161 is arranged on the outer cover 160. A second sound inlet hole 152 is arranged on the side of the inner cover 150, and the inner cover 150 also has a sound transmission channel 153, which is connected to the second sound inlet hole 152. A first sound transmission hole 154 is also arranged on the top wall of the first cavity 151, and the first sound transmission hole 154 is connected to the sound transmission channel 153.

[0066] S4: Laminating the sound intake cover 140 to form a waterproof film 180 .

[0067] Specifically, a vacuum lamination technique can be used to coat the top surface of the outer cover 160 to form a waterproof membrane 180. The waterproof membrane 180 here can play a waterproof role and prevent water vapor from directly entering the first sound inlet 162.

[0068] In summary, the present embodiment provides a MEMS packaging structure 100 and a preparation method thereof, wherein a sound inlet cover 140 is provided on a substrate 110 and covers the outside of an ASIC chip 120 and a MEMS chip 130, and the inner cover 150 of the sound inlet cover 140 has a first cavity 151, and the outer cover 160 has a second cavity 161, a first sound inlet hole 162 is provided on the outer cover 160, and a second sound inlet hole 152 is provided on the side of the inner cover 150, and the first sound inlet hole 162 and the second sound inlet hole 152 are connected to each other. The first cavity 151 and the second cavity 161 are connected to each other, thereby forming a front sound cavity of the MEMS chip 130, increasing the volume of the sound inlet space, improving the sound pressure / sound signal, and thus improving the sensitivity and signal-to-noise ratio of the MEMS chip 130. At the same time, the sound is input through multiple sound inlet holes, and the sound is input through the second cavity 161 and the first cavity 151 respectively, so that the MEMS chip 130 is prevented from directly contacting with external sound pressure / sound. Therefore, when the sound pressure / sound changes beyond a certain value, the first cavity 151 and the second cavity 161 can play a buffering role, so as to prevent the silicon diaphragm from breaking due to high-intensity sound pressure / sound impact, thereby greatly improving the applicability of the MEMS chip 130. At the same time, by providing the sound inlet groove 164, the first sound inlet hole 162 is provided on the side wall of the sound inlet groove 164, so as to avoid the contact between the suction nozzle and the first sound inlet hole 162 during the mounting process, so that when the suction nozzle surface is contaminated and picked up, the suction nozzle foreign matter falls into the first sound inlet hole 162, resulting in the problem of cavity foreign matter and silicon diaphragm vibration damage, thereby improving the MEMS sensitivity, signal-to-noise ratio, and frequency response performance. In addition, the waterproof membrane 180 can be prevented from blocking the first sound inlet hole 162, thereby ensuring the sound inlet effect, and the sound inlet groove 164 can play a role in sound inlet transition, thereby preventing the sound pressure / sound from directly entering the second cavity 161. At the same time, by providing the third cavity 163, the volume of the sound cavity behind the MEMS chip 130 is increased, which can further improve the sensitivity and signal-to-noise ratio of the MEMS chip 130.

[0069] Second embodiment

[0070] See also Figure 3 and Figure 4 This embodiment provides a MEMS packaging structure 100, whose basic structure, principle and technical effects are the same as those of the first embodiment. For the sake of brief description, for parts not mentioned in this embodiment, reference may be made to the corresponding contents in the first embodiment.

[0071] In this embodiment, the chamber partition 170 includes a first isolation portion 171 and a second isolation portion 173 which are integrally arranged. The first isolation portion 171 is connected to the inner wall of the outer cover body 160. The second isolation portion 173 is located between the inner cover body 150 and the outer cover body 160 and is connected to the substrate 110. The sound guide hole 112 is located between the second isolation portion 173 and the outer cover body 160. A fourth cavity 165 is also formed between the second isolation portion 173 and the outer wall of the inner cover body 150, and the fourth cavity 165 is connected to the second cavity 161.

[0072] Specifically, the chamber partition 170 in this embodiment also separates the area between the inner cover 150 and the outer cover 160. Unlike the first embodiment, the chamber partition 170 in this embodiment uses the second isolation part 173 to bend the separation line down to the substrate 110, so that the second isolation part 173 and the inner cover 150 are expanded to form a fourth cavity 165, wherein the fourth cavity 165 and the second cavity 161 can be directly connected, and the separation line between the two is the extension line of the first isolation part 171. It should be noted that the first isolation part 171 is arranged in a vertical direction, the second isolation part 173 is in a bent state, has a horizontal part and a vertical part, and the bottom of the second isolation part 173 is connected to the substrate 110.

[0073] In this embodiment, a sound inlet groove 164 may also be provided at the top of the outer cover 160, and the sound inlet groove 164 is located between the second cavity 161 and the third cavity 163, and the first sound inlet hole 162 is not provided on the sound inlet groove 164. Here, the sound inlet groove 164 can play the role of a transition chamber and a partition chamber, and can make a certain distinction in space between the second cavity 161 and the fourth cavity 165, and there is a certain gap between the bottom wall of the sound inlet groove 164 and the outer wall of the inner cover 150, which can form a sound transmission channel, connecting the second cavity 161 and the fourth cavity 165 as a whole. In addition, by providing the sound inlet groove 164, the bonding force between the waterproof membrane 180 and the outer cover 160 can be improved, thereby achieving effective bonding of the waterproof membrane 180.

[0074] In this embodiment, the sound inlet groove 164 passes through the inner cover 150, and a bridge conductive shell 166 is further provided in the sound inlet groove 164, and the two ends of the bridge conductive shell 166 are respectively conductive to the second cavity 161 and the fourth cavity 165, and a third sound inlet hole 167 is provided on the bridge conductive shell 166, so that the sound inlet groove 164 is connected with the second cavity 161 and the fourth cavity 165. Specifically, the third sound inlet hole 167 is provided at the bottom of the bridge conductive shell 166, and in this embodiment, the transmission of external sound pressure / sound can be achieved through the third sound inlet hole 167, and at the same time, the third sound inlet hole 167 is provided at the bottom of the bridge conductive shell 166, which can also avoid being directly opposite to the external space, and can also avoid the influence of the suction nozzle and the waterproof film 180 on the sound inlet hole during mounting.

[0075] It should be noted that the bridging conductive shell 166 can be single or multiple and spaced apart, and each bridging conductive shell 166 can conduct electricity between the second cavity 161 and the fourth cavity 165 .

[0076] In this embodiment, a second sound transmission hole 155 is provided on the side wall of the inner cover 150 combined with the fourth cavity 165, and the fourth cavity 165 is connected to the first cavity 151 through the second sound transmission hole 155. By providing the second sound transmission hole 155, direct communication between the fourth cavity 165 and the first cavity 151 can be achieved, thereby further increasing the sound pressure / sound transmission path and achieving sound pressure / sound diversion.

[0077] The MEMS packaging structure 100 provided in this embodiment further increases the volume of the front sound cavity by designing the fourth cavity 165, thereby improving the sensitivity and signal-to-noise ratio of the MEMS chip 130. At the same time, by setting the second sound transmission hole 155, the first cavity 151 has more sound intake paths, achieving sound pressure / sound diversion, which is conducive to achieving sound pressure / sound buffering, avoiding the rupture of the silicon diaphragm caused by high-intensity sound pressure / sound impact, and further improving product reliability.

[0078] Third embodiment

[0079] See also Figure 5 This embodiment provides a MEMS packaging structure 100, whose basic structure, principle and technical effects are the same as those of the first embodiment or the third embodiment. For the sake of brief description, parts not mentioned in this embodiment may refer to the corresponding contents in the first embodiment or the third embodiment.

[0080] In this embodiment, the chamber partition 170 includes a first isolation portion 171 and a second isolation portion 173 which are integrally arranged. The first isolation portion 171 is connected to the inner wall of the outer cover body 160. The second isolation portion 173 is located between the inner cover body 150 and the outer cover body 160 and is connected to the substrate 110. The sound guide hole 112 is located between the second isolation portion 173 and the outer cover body 160. A fourth cavity 165 is also formed between the second isolation portion 173 and the outer wall of the inner cover body 150, and the fourth cavity 165 is connected to the second cavity 161.

[0081] In this embodiment, a sound inlet groove 164 is further provided on the top of the outer cover 160, and the sound inlet groove 164 is located between the second cavity 161 and the third cavity 163, and the first sound inlet hole 162 is provided on the side wall and the bottom wall of the sound inlet groove 164 that are connected to the second cavity 161, so that the first sound inlet hole 162 passes through the second cavity 161. Specifically, the first sound inlet holes 162 can be distributed on the side wall and the bottom wall of the sound inlet groove 164, and the first sound inlet holes 162 are all connected to the second cavity 161, realizing multi-hole and multi-directional sound inlet, thereby improving the sound pressure / sound entering the channel range, and then improving product performance.

[0082] In this embodiment, the sound inlet groove 164 passes through the inner cover 150, and a bridge conductive shell 166 is further provided in the sound inlet groove 164, and the two ends of the bridge conductive shell 166 are respectively conductive to the second cavity 161 and the fourth cavity 165, and a third sound inlet hole 167 is provided on the bridge conductive shell 166, so that the sound inlet groove 164 is connected with the second cavity 161 and the fourth cavity 165. Specifically, the third sound inlet hole 167 is provided at the bottom of the bridge conductive shell 166, and in this embodiment, the transmission of external sound pressure / sound can be achieved through the third sound inlet hole 167, and at the same time, the third sound inlet hole 167 is provided at the bottom of the bridge conductive shell 166, which can also avoid being directly opposite to the external space, and can also avoid the influence of the suction nozzle and the waterproof film 180 on the sound inlet hole during mounting.

[0083] It should be noted that when the waterproof membrane 180 is formed by lamination, even if the material of the waterproof membrane 180 partially penetrates into the sound inlet groove 164, it will not affect the third sound inlet hole 167 located at the bottom of the bridging conductive shell 166, thereby further preventing the waterproof membrane 180 from completely blocking the sound inlet hole.

[0084] In summary, the MEMS packaging structure 100 provided in this embodiment can expand the sound intake channel by setting the first sound intake hole 162 on the side wall and the bottom wall of the sound intake groove 164 and combining the setting of the third sound intake hole 167, thereby achieving a better sound intake effect.

[0085] Fourth embodiment

[0086] See also Figure 6 and Figure 7 This embodiment provides a MEMS packaging structure 100, whose basic structure, principle and technical effects are the same as those of the first embodiment, the second embodiment or the third embodiment. For the sake of brief description, parts not mentioned in this embodiment may refer to the corresponding contents in the first embodiment, the second embodiment or the third embodiment.

[0087] In this embodiment, the chamber partition 170 includes an integrally arranged first isolation portion 171 and a second isolation portion 173, the first isolation portion 171 is connected to the inner wall of the outer cover 160, the second isolation portion 173 is located between the inner cover 150 and the outer cover 160, and is connected to the substrate 110, the sound guide hole 112 is located between the second isolation portion 173 and the outer cover 160, and a fourth cavity 165 is formed between the second isolation portion 173 and the outer wall of the inner cover 150, and the fourth cavity 165 is connected to the second cavity 161. At the same time, the sound inlet groove 164 is not provided in this embodiment, and the first isolation portion 171 and the second isolation portion 173 separate the local area between the inner cover 150 and the outer cover 160.

[0088] In this embodiment, the sound inlet groove 164 passes through the inner cover 150, and a bridge conductive shell 166 is further provided in the sound inlet groove 164, and the two ends of the bridge conductive shell 166 are respectively conductive to the second cavity 161 and the fourth cavity 165, and a third sound inlet hole 167 is provided on the bridge conductive shell 166, so that the sound inlet groove 164 is connected with the second cavity 161 and the fourth cavity 165. Specifically, the third sound inlet hole 167 is provided at the bottom of the bridge conductive shell 166, and in this embodiment, the transmission of external sound pressure / sound can be achieved through the third sound inlet hole 167, and at the same time, the third sound inlet hole 167 is provided at the bottom of the bridge conductive shell 166, which can also avoid being directly opposite to the external space, and can also avoid the influence of the suction nozzle and the waterproof film 180 on the sound inlet hole during mounting.

[0089] In this embodiment, the first isolating portion 171 is coupled to the side wall of the sound inlet groove 164 that is combined with the second cavity 161, so that the periphery of the bridge conductive shell 166 forms an annular channel 168, and the bridge conductive shell is also provided with a fourth sound inlet hole 169, which is arranged opposite to the third sound inlet hole 167. Specifically, the first isolating portion 171 is in a state of being recessed to the right at the sound inlet groove 164, so that the sound inlet groove 164 can be partially shielded, so that the lower part of the sound inlet groove 164 is a semi-enclosed space, and the bridge conductive shell 166 is located in the semi-enclosed space, and an annular channel 168 is formed on its periphery, and the annular channel 168 can be upwardly communicated with the external space through the gaps at the front and rear ends, so that on the one hand, the opening area of ​​the sound inlet groove 164 is reduced, and a large amount of infiltration of the waterproof membrane 180 is avoided, and on the other hand, the third sound inlet hole 167 and the fourth sound inlet hole 169 can be communicated with the external space, ensuring the sound inlet effect.

[0090] In summary, the MEMS packaging structure 100 provided in this embodiment further expands the sound input channel by providing the annular channel 168 and the fourth sound input hole 169, and the third sound input hole 167 and the fourth sound input hole 169 will not be affected by the suction nozzle and the waterproof film 180, thereby ensuring the mounting effect.

[0091] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A MEMS packaging structure, characterized in that: include: substrate; An ASIC chip and a MEMS chip are arranged on the substrate at intervals; A sound inlet cover body is arranged on the substrate, and the sound inlet cover body covers the outside of the ASIC chip and the MEMS chip; The sound inlet cover comprises an inner cover and an outer cover which are integrally arranged, the inner cover having a first cavity, the ASIC chip and the MEMS chip being accommodated in the first cavity, the outer cover having a spacer cover arranged outside the inner cover and having a second cavity, the outer cover having a first sound inlet hole communicating with the second cavity, the side of the inner cover having a second sound inlet hole, and the inner cover also having a sound transmission channel communicating with the second sound inlet hole, the top wall of the first cavity also having a first sound transmission hole communicating with the sound transmission channel; The outer cover body also has a third cavity, and a chamber partition is also arranged in the outer cover body, and the chamber partition is used to separate the space between the inner cover body and the outer cover body into a second cavity and a third cavity. A back sound hole is also arranged on the substrate, and the MEMS chip cover is arranged on the back sound hole, and the back sound hole is connected with the third cavity.

2. The MEMS packaging structure according to claim 1, characterized in that: A sound guide hole is also provided on the substrate, and the sound guide hole is located between the inner cover body and the outer cover body and is connected to the third cavity. A sound guide channel is also provided in the substrate, and both ends of the sound guide channel extend to the sound guide hole and the back sound hole respectively, so that the sound guide hole and the back sound hole are connected.

3. The MEMS packaging structure according to claim 2, characterized in that: Both sides of the chamber partition are connected to the outer wall of the inner cover body and the inner wall of the outer cover body respectively.

4. The MEMS packaging structure according to claim 2, characterized in that: A sound inlet groove is also provided on the top of the outer cover body, and the sound inlet groove is located between the second cavity and the third cavity, and the first sound inlet hole is provided on the side wall of the sound inlet groove connected with the second cavity, so that the first sound inlet hole passes through to the second cavity.

5. The MEMS packaging structure according to claim 2, characterized in that: The chamber partition includes a first isolation part and a second isolation part which are integrally arranged, the first isolation part is connected to the inner wall of the outer cover body, the second isolation part is located between the inner cover body and the outer cover body, and is connected to the substrate, the sound guide hole is located between the second isolation part and the outer cover body, and a fourth cavity is also formed between the second isolation part and the outer side wall of the inner cover body, and the fourth cavity is connected to the second cavity.

6. The MEMS packaging structure according to claim 5, characterized in that: A sound inlet groove is also provided on the top of the outer cover body, and the sound inlet groove is located between the second cavity and the third cavity. The first sound inlet hole is provided on the side wall and bottom wall of the sound inlet groove that are connected to the second cavity, so that the first sound inlet hole passes through to the second cavity.

7. The MEMS packaging structure according to claim 6, characterized in that: The sound inlet groove passes through the inner cover body, and a bridging conductive shell is also provided in the sound inlet groove, the two ends of the bridging conductive shell are respectively connected to the second cavity and the fourth cavity, and a third sound inlet hole is provided on the bridging conductive shell to connect the sound inlet groove with the second cavity and the fourth cavity.

8. The MEMS packaging structure according to claim 7, characterized in that: The first isolation portion is joined to the side wall of the sound inlet groove combined with the second cavity, so that the periphery of the bridge conduction shell forms an annular channel, and the bridge conduction shell is also provided with a fourth sound inlet hole, which is arranged opposite to the third sound inlet hole.

9. The MEMS packaging structure according to claim 5, characterized in that: A second sound transmission hole is provided on the side wall of the inner cover body combined with the fourth cavity, and the fourth cavity is connected with the first cavity through the second sound transmission hole.

10. The MEMS packaging structure according to any one of claims 1 to 9, characterized in that: A waterproof membrane is also provided on the top side of the outer cover body, and the waterproof membrane covers the surface of the outer cover body.

11. A method for preparing a MEMS packaging structure, characterized in that: Used to prepare the MEMS packaging structure according to any one of claims 1 to 10, the preparation method comprising: providing a substrate; Mounting the ASIC chip and the MEMS chip on the substrate at intervals; Mounting a sound inlet cover on the substrate, and placing the sound inlet cover outside the ASIC chip and the MEMS chip; Among them, the sound inlet cover body includes an inner cover body and an outer cover body which are integrally arranged, the inner cover body has a first cavity, the ASIC chip and the MEMS chip are both accommodated in the first cavity, the outer cover body spacer is arranged outside the inner cover body, and has a second cavity, the outer cover body is provided with a first sound inlet hole connected to the second cavity, the side of the inner cover body is provided with a second sound inlet hole, and the inner cover body also has a sound transmission channel, the sound transmission channel is connected to the second sound inlet hole, and the top wall of the first cavity is also provided with a first sound transmission hole, the first sound transmission hole is connected to the sound transmission channel.

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