Chip packaging structure and method for preparing chip packaging structure

Abstract

The embodiment of the present invention provides a chip packaging structure and a method for preparing the chip packaging structure, which relates to the field of semiconductor packaging technology. The chip packaging structure includes a substrate, a silicon microphone chip, a control chip and a packaging cover plate. The packaging cover plate includes an inner cover plate, an outer cover plate and a sound input box. By setting the sound input box, and opening sound input holes on the side wall of the sound input box, and the sound input holes are arranged in all directions, the sound reception range is wider and the sound reception effect is better. It can also prevent the sound pressure from being directly transmitted to the second sound cavity, and prevent the sound pressure from impacting the silicon microphone chip. Compared with the prior art, the present invention greatly increases the volume of the sound cavity through the arrangement of the first sound cavity, the second sound cavity and the sound input cavity, and adopts multiple directions for sound reception, which greatly improves the sensitivity and signal-to-noise ratio of the product. At the same time, it can prevent the sound pressure from impacting the silicon microphone chip and causing the silicon diaphragm to rupture. Even if the sound pressure changes greatly, it will not affect the silicon diaphragm of the silicon microphone chip, thereby ensuring the reliability of the product.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor packaging technology, and in particular to a chip packaging structure and a method for preparing the chip 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. 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 interference, thereby changing the capacitance value between the silicon diaphragm and the silicon back plate, thereby converting the sound pressure signal into a voltage signal. The existing MEMS silicon microphone product design sound enters the MEMS chip and the metal cover from a single hole / single direction, and the sound cavity of the MEMS chip is small. When the sound signal is very weak, the sound pressure signal is weaker, which leads to a decrease in the sensitivity and signal-to-noise ratio of the MEMS silicon microphone product. At the same time, since the silicon diaphragm on the MEMS chip is very sensitive to changes in sound pressure, the external sound pressure in the existing technology directly contacts the silicon diaphragm on the MEMS chip. Therefore, when the intensity of the sound pressure change exceeds a certain value, the silicon diaphragm will break due to the high-intensity sound pressure impact. Summary of the invention

[0003] The objectives of the present invention include, for example, providing a chip packaging structure and a method for preparing a chip packaging structure, which can increase the volume of the sound cavity, improve product sensitivity and signal-to-noise ratio, while avoiding sound pressure shock that may cause silicon diaphragm rupture, thereby ensuring product reliability.

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

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

[0006] substrate;

[0007] A silicon microphone chip and a control chip mounted on the substrate;

[0008] A packaging cover plate mounted on the substrate and covering the silicon microphone chip and the control chip;

[0009] Among them, the packaging cover plate includes an inner cover plate, an outer cover plate and a sound input box, the inner cover plate is arranged on the substrate and has a first sound cavity, the silicon microphone chip and the control chip are both accommodated in the first sound cavity, the outer cover plate is arranged outside the inner cover plate, and has a second sound cavity, the first sound cavity and the second sound cavity are connected, the sound input box is arranged on the outer cover plate and protrudes upward relative to the outer cover plate, and the sound input box has a sound input cavity connected to the second sound cavity, and a plurality of sound input holes are opened on the side walls around the sound input box, and the plurality of sound input holes are all connected to the sound input cavity.

[0010] In an optional embodiment, a first sound transmission hole is provided on the top wall of the inner cover plate, and the first sound transmission hole is used to conduct the first sound cavity and the second sound cavity.

[0011] In an optional embodiment, the first sound transmission hole and the sound input box are staggered so that the sound input cavity and the first sound transmission hole are staggered.

[0012] In an optional embodiment, a second sound transmission hole is provided on the side wall of the inner cover plate, and the second sound transmission hole is used to conduct the first sound cavity and the second sound cavity.

[0013] In an optional embodiment, there are multiple sound input boxes, and the multiple sound input boxes are distributed at intervals at the center and both sides of the top of the outer cover plate.

[0014] In an optional embodiment, there are two sound input boxes, and the two sound input boxes are arranged on both side edges of the top of the outer cover plate.

[0015] In an optional embodiment, the side walls around the sound inlet box are recessed inwards and form an annular groove, and the plurality of sound inlet holes are located above the annular groove.

[0016] In an optional embodiment, the chip packaging structure also includes a plastic package body, which is arranged on the substrate and coated on the outside of the outer cover plate, and the plastic package body partially covers the sound input box, and the multiple sound input holes are all located above the plastic package body.

[0017] In an optional embodiment, a height of a side surface of the plastic packaging body away from the substrate relative to the substrate is greater than or equal to a height of a side wall of the annular groove away from the substrate relative to the substrate, so that the plastic packaging body covers the annular groove.

[0018] In an optional embodiment, there are multiple annular grooves, and the multiple annular grooves are spaced apart on the side walls around the sound inlet box, and each of the sound inlet holes is located above the multiple annular grooves, and the plastic package body is covered on the multiple annular grooves.

[0019] In an optional embodiment, a laser character groove is provided on a surface of the plastic packaging body away from the substrate, and a depth of the laser character groove is less than or equal to a distance between the surface of the plastic packaging body away from the substrate and the outer cover plate.

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

[0021] providing a substrate;

[0022] Mounting a silicon microphone chip and a control chip on the substrate;

[0023] Mounting a packaging cover plate on the substrate, wherein the packaging cover plate is arranged outside the silicon microphone chip and the control chip;

[0024] Among them, the packaging cover plate includes an inner cover plate, an outer cover plate and a sound input box, the inner cover plate is arranged on the substrate and has a first sound cavity, the silicon microphone chip and the control chip are both accommodated in the first sound cavity, the outer cover plate is arranged outside the inner cover plate, and has a second sound cavity, the first sound cavity and the second sound cavity are connected, the sound input box is arranged on the outer cover plate and protrudes upward relative to the outer cover plate, and the sound input box has a sound input cavity connected to the second sound cavity, and a plurality of sound input holes are opened on the side walls around the sound input box, and the plurality of sound input holes are all connected to the sound input cavity.

[0025] In an optional embodiment, after the step of mounting a package cover on the substrate, the preparation method further comprises:

[0026] forming a plastic package on the substrate;

[0027] The plastic package body is coated on the outside of the outer cover plate and partially covers the sound inlet box, and the plurality of sound inlet holes are all located above the plastic package body.

[0028] The beneficial effects of the embodiments of the present invention include, for example:

[0029] The embodiment of the present invention provides a chip packaging structure and a method for preparing the chip structure, wherein a packaging cover plate is disposed on a substrate, the inner cover plate of the packaging cover plate has a first sound cavity, the outer cover plate has a second sound cavity, the first sound cavity and the second sound cavity are connected, and the volume of the sound input cavity is increased. At the same time, a sound input box is also disposed on the outer cover plate, and the sound input box has a sound input cavity connected to the second sound cavity, and a plurality of sound input holes are provided on the side walls around the sound input box, and the plurality of sound input holes are all connected to the sound input cavity. By providing a sound input box, and the sound input holes are provided on the side walls of the sound input box, and the sound input holes are provided along the four directions, on the one hand, a multi-channel sound input structure can be realized, the sound input efficiency of the product can be improved, and the sound reception range is wider and the sound reception effect is better. On the other hand, it can prevent the sound pressure from being directly transmitted into the second sound cavity, and prevent the sound pressure from impacting the silicon microphone chip. Compared with the prior art, the present invention greatly increases the volume of the sound cavity by setting up the first sound cavity, the second sound cavity and the sound input cavity, and adopts multi-hole sound input and multiple directions to collect sound, which greatly improves the sensitivity and signal-to-noise ratio of the product. At the same time, it adopts side wall sound input and sets a sound input box to avoid sound pressure impact on the silicon microphone chip and cause the silicon diaphragm to rupture. Even if the sound pressure changes greatly, it will not affect the silicon diaphragm of the silicon microphone chip, thereby ensuring the reliability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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.

[0031] Figure 1 A cross-sectional structural diagram of a chip packaging structure provided by a first embodiment of the present invention;

[0032] Figure 2 A first deformed cross-sectional structural diagram of a chip packaging structure provided by the first embodiment of the present invention;

[0033] Figure 3 A second deformed cross-sectional structural diagram of the chip packaging structure provided by the first embodiment of the present invention;

[0034] Figure 4 A flowchart of a method for preparing a chip packaging structure according to a first embodiment of the present invention;

[0035] Figure 5 A cross-sectional structural diagram of a chip packaging structure provided by a second embodiment of the present invention;

[0036] Figure 6 for Figure 5 A partial enlarged schematic diagram of middle VI;

[0037] Figure 7 A top view of a chip packaging structure provided by a second embodiment of the present invention;

[0038] Figure 8 A cross-sectional structural diagram of a chip packaging structure provided by a third embodiment of the present invention;

[0039] Fig. 9 for Figure 8 A partial enlarged schematic diagram of Figure IX.

[0040] Icon: 100-chip packaging structure; 110-substrate; 120-silicon microphone chip; 130-control chip; 140-packaging cover; 150-inner cover; 151-first sound cavity; 152-first sound transmission hole; 153-second sound transmission hole; 160-outer cover; 161-second sound cavity; 170-sound inlet box; 171-sound inlet cavity; 172-sound inlet hole; 173-ring groove; 180-plastic package; 181-laser character groove. DETAILED DESCRIPTION

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] As disclosed in the background technology, in the prior art, for MEMS packaging structures, a single hole or a single direction is usually used for sound intake, and the sound receiving range is narrow, and the volume of the internal sound cavity is small. This results in that when the sound signal is very weak, the sound pressure signal is weaker, and it is difficult to accurately conduct the sound pressure, resulting in a decrease in the sensitivity and signal-to-noise ratio of MEMS silicon microphone products. In addition, since the silicon diaphragm on the MEMS chip is very sensitive to changes in sound pressure, the external sound pressure in the prior art directly contacts the silicon diaphragm on the MEMS chip, so when the intensity of the sound pressure change exceeds a certain value, the silicon diaphragm will rupture due to the high-intensity sound pressure impact.

[0047] In order to solve the above problems, the present invention provides a novel chip packaging structure and a method for preparing the chip packaging structure. It should be noted that the features in the embodiments of the present invention can be combined with each other without conflict.

[0048] First embodiment

[0049] See also Figure 1 This embodiment provides a chip packaging structure 100, which can increase the volume of the sound cavity and improve the sound input range, improve the product sensitivity and signal-to-noise ratio, and at the same time avoid the rupture of the silicon diaphragm caused by sound pressure / sound impact, thereby ensuring the reliability of the product.

[0050] The chip packaging structure 100 provided in this embodiment includes a substrate 110, a silicon-wheat chip 120, a control chip 130 and a packaging cover plate 140. The silicon-wheat chip 120 and the control chip 130 are mounted on the substrate 110 at intervals, and the packaging cover plate 140 is mounted on the substrate 110 and covers the silicon-wheat chip 120 and the control chip 130. The silicon-wheat chip 120 and the control chip 130 are electrically connected to the substrate 110 by wire bonding, that is, the control chip 130 is electrically connected to the substrate 110 by wire bonding, and the silicon-wheat chip 120 and the control chip 130 are electrically connected by wire bonding.

[0051] It should be noted that, in this embodiment, the silicon microphone chip 120 is a MEMS chip, and the control chip 130 can be an ASIC chip (ASIC, Application Specific Integrated Circuit).

[0052] The packaging cover 140 includes an inner cover 150, an outer cover 160 and a sound input box 170. The inner cover 150 is covered on the substrate 110 and has a first sound cavity 151. The silicon microphone chip 120 and the control chip 130 are both accommodated in the first sound cavity 151. The outer cover 160 is covered outside the inner cover 150 and has a second sound cavity 161. The first sound cavity 151 and the second sound cavity 161 are connected. The sound input box 170 is arranged on the outer cover 160 and protrudes upward relative to the outer cover 160. The sound input box 170 has a sound input cavity 171 connected to the second sound cavity 161. A plurality of sound input holes 172 are opened on the side walls around the sound input box 170, and the plurality of sound input holes 172 are all connected to the sound input cavity 171.

[0053] In this embodiment, the inner cover plate 150, the outer cover plate 160 and the sound box 170 are integrally arranged and prepared in advance before chip packaging, wherein the inner cover plate 150 and the outer cover plate 160 can be connected through the front and rear side surface shells. Figure 1 What is shown is only a cross-sectional view of the package cover plate 140 , which may extend in the front-to-back direction to form a three-dimensional package cover plate 140 .

[0054] It should be noted that the first sound cavity 151 and the second sound cavity 161 are connected here and serve as the front sound cavity of the silicon microphone chip 120. Compared with the conventional structure, the volume of the front sound cavity of the silicon microphone chip 120 is greatly increased here, thereby greatly increasing the signal-to-noise ratio and sensitivity of the silicon microphone chip 120. By setting the sound inlet box 170, and opening the sound inlet hole 172 on the side wall of the sound inlet box 170, and the sound inlet hole 172 is arranged along the four directions, on the one hand, it can realize the sound inlet structure of multiple channels, improve the sound inlet efficiency of the product, and have a wider sound reception range and better sound reception effect. At the same time, it increases the transmission area of ​​sound pressure / sound into the sound inlet cavity 171, increases the internal sound pressure, thereby improving the signal-to-noise ratio and performance of the silicon microphone product, and further improves the sensitivity of the silicon microphone chip 120. On the other hand, it can prevent the sound pressure / sound from being directly transmitted into the second sound cavity 161, and prevent the sound pressure / sound from directly impacting the MEMS chip.

[0055] In this embodiment, the top wall of the inner cover plate 150 is provided with a first sound transmission hole 152, and the first sound transmission hole 152 is used to conduct the first sound cavity 151 and the second sound cavity 161. Specifically, there can be multiple first sound transmission holes 152, and the multiple first sound transmission holes 152 are used to conduct the upper second sound cavity 161 and the lower first sound cavity 151.

[0056] In this embodiment, the first sound transmission hole 152 and the sound input box 170 are staggered so that the sound input cavity 171 is staggered with the first sound transmission hole 152. Specifically, the first sound transmission hole 152 and the sound input cavity 171 are staggered here, which can avoid direct transmission of sound pressure / sound, so that the purpose of sound pressure / sound buffering can be achieved here, and the sound pressure / sound impact on the silicon microphone chip 120 caused by excessive changes in sound pressure / sound is further avoided, thereby ensuring the reliability of the silicon microphone chip 120.

[0057] In this embodiment, the side wall of the inner cover plate 150 is provided with a second sound transmission hole 153, and the second sound transmission hole 153 is used to conduct the first sound cavity 151 and the second sound cavity 161. Specifically, the second sound transmission holes 153 are provided on the side walls on both sides of the inner cover plate 150, so that the sound pressure / sound entering from the sound inlet cavity 171 can not only be transmitted to the first sound cavity 151 from the first sound transmission hole 152, but also can be transmitted through the second sound transmission hole 153, further increasing the range of the sound inlet channel.

[0058] In this embodiment, there are multiple sound input boxes 170, and the multiple sound input boxes 170 are spaced apart and distributed at the center and both sides of the top of the outer cover plate 160. Specifically, by providing multiple sound input boxes 170, on the one hand, stress balance can be achieved at various locations to avoid warping during subsequent plastic sealing, and on the other hand, the number of sound input holes 172 and the sound receiving range can be further increased, thereby further improving the sensitivity and signal-to-noise ratio of the silicon microphone chip 120.

[0059] like Figure 2 In other preferred embodiments of the present invention, there may be two sound input boxes 170, which are arranged at both side edges of the top of the outer cover plate 160. Specifically, the sound input boxes 170 may be arranged on the left and right sides, respectively, so as to prevent the plastic package from warping.

[0060] like Figure 3 In other preferred embodiments of the present invention, the sound input box 170 may also be single, and the single sound input box 170 is arranged in the middle position of the outer cover plate 160 .

[0061] In the present embodiment, the side walls around each sound inlet box 170 are recessed inward and form an annular groove 173, and the plurality of sound inlet holes 172 are all located above the annular groove 173. Specifically, by providing the annular groove 173, the sound inlet cavity 171 can be made to present an I-shape, which is more conducive to the internal transmission of sound pressure / sound, and plays a role in sound pressure / sound buffering. At the same time, the position of the annular groove 173 here is higher than the position of the outer cover plate 160, and can serve as a plastic sealing mark in the subsequent plastic sealing process, so that the plastic sealing material is plastic sealed to the annular groove 173. The annular groove 173 also increases the surface area of ​​the side wall of the sound inlet box 170, so that the bonding force between the subsequent plastic sealing material and the sound inlet box 170 can be improved, which is beneficial to the stability of the product structure.

[0062] See also Figure 4 This embodiment further provides a method for preparing a chip packaging structure 100, which is used to prepare the aforementioned chip packaging structure 100. The preparation method comprises the following steps:

[0063] S1: Provide a substrate 110.

[0064] Specifically, a substrate 110 with a pad may be provided, wherein the pad is located in a mounting area of ​​the substrate 110 , the mounting area is used to mount the silicon microphone chip 120 and the control chip 130 , and the surrounding area of ​​the mounting area is used to package the cover plate 140 .

[0065] S2: Mounting the silicon microphone chip 120 and the control chip 130 on the substrate 110 .

[0066] Specifically, conventional chip mounting processes can be used to mount the chip in the mounting area on the substrate 110. After mounting, the electrical connection between the control chip 130 and the substrate 110 can be completed by wire bonding, and the electrical connection between the control chip 130 and the silicon microphone chip 120 can be completed by wire bonding.

[0067] S3 : mounting the package cover plate 140 on the substrate 110 .

[0068] Specifically, the package cover plate 140 is disposed outside the control chip 130 and the silicon microphone chip 120. The bottom of the package cover plate 140 can be adhered to the substrate 110 by using a bonding or welding process, and the sealing performance needs to be ensured, thereby ensuring normal sound transmission.

[0069] Among them, the packaging cover plate 140 includes an inner cover plate 150, an outer cover plate 160 and a sound input box 170. The inner cover plate 150 is covered on the substrate 110 and has a first sound cavity 151. The silicon microphone chip 120 and the control chip 130 are both accommodated in the first sound cavity 151. The outer cover plate 160 is covered outside the inner cover plate 150 and has a second sound cavity 161. The first sound cavity 151 and the second sound cavity 161 are connected. The sound input box 170 is arranged on the outer cover plate 160 and protrudes upward relative to the outer cover plate 160. The sound input box 170 has a sound input cavity 171 connected to the second sound cavity 161. A plurality of sound input holes 172 are opened on the side walls around the sound input box 170, and the plurality of sound input holes 172 are all connected to the sound input cavity 171.

[0070] In summary, this embodiment provides a chip packaging structure 100, wherein the packaging cover plate 140 is covered on the substrate 110, the inner cover plate 150 of the packaging cover plate 140 has a first sound cavity 151, and the outer cover plate 160 has a second sound cavity 161, the first sound cavity 151 and the second sound cavity 161 are connected, and the volume of the sound inlet cavity 171 is increased. At the same time, a sound inlet box 170 is also provided on the outer cover plate 160, and the sound inlet box 170 has a sound inlet cavity 171 connected with the second sound cavity 161, and a plurality of sound inlet holes 172 are provided on the side walls around the sound inlet box 170, and the plurality of sound inlet holes 172 are all connected with the sound inlet cavity 171. By providing the sound inlet box 170, and the sound inlet holes 172 are provided on the side walls of the sound inlet box 170, and the sound inlet holes 172 are provided along the four directions, on the one hand, a sound inlet structure of multiple channels can be realized, the sound inlet efficiency of the product is improved, and the sound reception range is wider and the sound reception effect is better. On the other hand, it can prevent the sound pressure / sound from directly entering the second sound cavity 161, and prevent the sound pressure / sound from impacting the MEMS chip. At the same time, by respectively opening the first sound transmission hole 152 and the second sound transmission hole 153 on the top wall and the side wall of the inner cover plate 150, the range of the sound input channel can be further increased, greatly improving the sound pickup effect and quality of the product.

[0071] Second embodiment

[0072] See also Figures 5 to 7 This embodiment provides a chip 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.

[0073] In this embodiment, the chip packaging structure 100 further includes a plastic package 180, which is disposed on the substrate 110 and coated on the outside of the outer cover plate 160, and the plastic package 180 partially covers the sound inlet box 170, and the plurality of sound inlet holes 172 are all located above the plastic package 180. Specifically, the sound inlet box 170 here can be single, and the single sound inlet box 170 is disposed in the middle position of the outer cover plate 160, and the plastic package 180 is completely coated on the outer cover plate 160, and can cover the connection between the outer cover plate 160 and the substrate 110, so as to protect the connection, and can prevent the desoldering phenomenon between the outer cover plate 160 and the substrate 110 during the drop test.

[0074] In this embodiment, the height of the side surface of the plastic package body 180 away from the substrate 110 relative to the substrate 110 is greater than or equal to the height of the side wall of the annular groove 173 away from the substrate 110 relative to the substrate 110, so that the plastic package body 180 is covered by the annular groove 173. Preferably, the annular groove 173 here is a plastic packaging mark, that is, the plastic packaging material is covered to the annular groove 173 and completely covers the annular groove 173. Due to the provision of the annular groove 173 structure, the surface area of ​​the side wall of the sound input box 170 is increased, thereby increasing the contact area with the plastic package body 180, thereby improving the bonding force between the sound input box 170 and the plastic package body 180, and avoiding the delamination of the plastic package body 180.

[0075] It should be noted that the plastic package 180 here does not completely cover the sound inlet box 170, but exposes the part above the ring groove 173. The sound inlet holes 172 on the sound inlet box 170 are all located above the ring groove 173 and above the plastic package 180, thereby ensuring normal sound intake of the sound inlet holes 172.

[0076] In the present embodiment, a laser character groove 181 is provided on the surface of the side of the plastic package 180 away from the substrate 110, and the depth of the laser character groove 181 is less than or equal to the distance between the surface of the side of the plastic package 180 away from the substrate 110 and the outer cover plate 160. Specifically, the package cover plate 140 here can be a metal cover plate, and the outer cover plate 160 can be used as a laser grooving stop layer to prevent the laser from breaking through the plastic package 180 and exposing the chip or the wire bonding layer. Preferably, the laser character groove 181 is located above the outer cover plate 160, and the depth is consistent with the thickness of the plastic package 180 at the groove. Using the outer cover plate 160 as a barrier layer can effectively prevent the transmission process from printing on the plastic package 180, and there is a problem that the laser power / energy is too large, resulting in too deep printing on the surface of the plastic package 180 and burning through the plastic package 180.

[0077] This embodiment also provides a method for preparing a chip packaging structure 100, the basic steps and principles and the technical effects produced 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.

[0078] It should be noted that in the present embodiment, there is a single sound input box 170, which is disposed in the middle position of the outer cover plate 160. In other preferred embodiments, there may be multiple sound input boxes 170, and multiple sound input boxes 170 are disposed in the middle position and at the edges of both sides of the outer cover plate 160, thereby relieving stress and preventing the plastic package body 180 from warping.

[0079] The method for preparing the chip packaging structure 100 provided in this embodiment is used to prepare the aforementioned chip packaging structure 100, and specifically comprises the following steps:

[0080] S1: Provide a substrate 110.

[0081] S2: Mounting the silicon microphone chip 120 and the control chip 130 on the substrate 110 .

[0082] S3 : mounting the package cover plate 140 on the substrate 110 .

[0083] Steps S1 to S3 are the same as those in the first embodiment, except that, in this embodiment, after step S3, the following steps are further performed:

[0084] S4 : forming a plastic package body 180 on the substrate 110 .

[0085] Specifically, the plastic package body 180 is coated on the outer cover plate 160 and partially covers the sound inlet box 170 , and the plurality of sound inlet holes 172 are all located above the plastic package body 180 .

[0086] After the preparation of the plastic package 180 is completed, a cutting operation is required. Here, the plastic package 180 can be separated along the cutting path using a diamond knife through a cutting process, thereby forming a single chip packaging structure 100 and completing the final process. The cutting path is set away from the sound inlet box 170, so the sound inlet hole 172 will not be affected during cutting.

[0087] This embodiment provides a chip packaging structure 100 and a preparation method thereof, wherein the plastic packaging body 180 is used to cover the annular groove 173 of the sound inlet box 170, thereby improving the bonding force between the plastic packaging body 180 and the sound inlet box 170 and preventing the plastic packaging body 180 from being delaminated. At the same time, the plastic packaging body 180 is covered on the outside of the outer cover plate 160, and can cover the welding / bonding part at the bottom of the outer cover plate 160, thereby effectively protecting the weak connection part, preventing the packaging cover plate 140 from welding off during the drop test, and ensuring the structural stability of the product.

[0088] Third embodiment

[0089] See also Figure 8 and Fig. 9 This embodiment provides a chip packaging structure 100, whose basic structure, principle and technical effects are the same as those of the first embodiment or the second 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 or the second embodiment.

[0090] In this embodiment, the chip packaging structure 100 also includes a plastic package 180, which is disposed on the substrate 110 and wrapped around the outer cover 160. The plastic package 180 partially wraps the sound inlet box 170, and multiple sound inlet holes 172 are all located above the plastic package 180.

[0091] In this embodiment, there are multiple annular grooves 173, which are arranged at intervals on the side walls around the sound inlet box 170, and each sound inlet hole 172 is located above the multiple annular grooves 173, and the plastic package 180 covers the multiple annular grooves 173. Specifically, the height of the sound inlet box 170 is greater than that of the first embodiment or the second embodiment, so that multiple annular grooves 173 can be formed on the side walls of the sound inlet box 170, and the multiple annular grooves 173 are arranged at intervals and in parallel, and the plastic package 180 can completely cover the multiple annular grooves 173, thereby further improving the bonding force between the plastic package 180 and the sound inlet box 170, and avoiding the phenomenon of stratification of the plastic package 180.

[0092] In addition, in this embodiment, multiple annular grooves 173 are used, so that the sound inlet cavity 171 has multiple I-shaped structures, which prevents the sound pressure / sound from being directly transmitted to the second sound cavity 161 in the vertical direction. At the same time, by providing multiple annular grooves 173, stress release can be achieved, further preventing the plastic package body 180 from warping.

[0093] Preferably, the present embodiment is described by taking two annular grooves 173 as an example. Of course, in other preferred embodiments, the annular grooves 173 may also be three, four or five, etc., extending in the vertical direction.

[0094] In summary, the chip packaging structure 100 provided in this embodiment can increase the bonding force between the plastic package 180 and the sound inlet box 170 by providing a plurality of annular grooves 173, thereby preventing the plastic package 180 from being delaminated, and can further play a role in sound pressure buffering, thereby preventing the sound pressure / sound from being directly transmitted to the second sound cavity 161. At the same time, it can also play a role in stress release, thereby preventing the plastic package 180 from warping.

[0095] 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 chip packaging structure, characterized in that: include: substrate; A silicon microphone chip and a control chip mounted on the substrate; A packaging cover plate mounted on the substrate and covering the silicon microphone chip and the control chip; Wherein, the packaging cover plate comprises an inner cover plate, an outer cover plate and a sound input box, the inner cover plate is arranged on the substrate and has a first sound cavity, the silicon microphone chip and the control chip are both accommodated in the first sound cavity, the outer cover plate is arranged outside the inner cover plate and has a second sound cavity, the first sound cavity and the second sound cavity are connected, the sound input box is arranged on the outer cover plate and protrudes upward relative to the outer cover plate, and the sound input box has a sound input cavity connected to the second sound cavity, and a plurality of sound input holes are opened on the side walls around the sound input box, and the plurality of sound input holes are all connected to the sound input cavity; The side walls around the sound inlet box are recessed inwards and form an annular groove, and the plurality of sound inlet holes are all located above the annular groove.

2. The chip packaging structure according to claim 1, characterized in that: The top wall of the inner cover plate is provided with a first sound transmission hole, and the first sound transmission hole is used for conducting the first sound cavity and the second sound cavity.

3. The chip packaging structure according to claim 2, characterized in that: The first sound transmission hole and the sound input box are staggered so that the sound input cavity and the first sound transmission hole are staggered.

4. The chip packaging structure according to claim 1 or 2, characterized in that: The side wall of the inner cover plate is provided with a second sound transmission hole, and the second sound transmission hole is used for conducting the first sound cavity and the second sound cavity.

5. The chip packaging structure according to claim 1, characterized in that: There are multiple sound input boxes, and the multiple sound input boxes are distributed at intervals at the center and both sides of the top of the outer cover plate.

6. The chip packaging structure according to claim 1, characterized in that: There are two sound input boxes, and the two sound input boxes are arranged on both side edges of the top of the outer cover plate.

7. The chip packaging structure according to claim 1, characterized in that: The chip packaging structure also includes a plastic package body, which is arranged on the substrate and covered outside the outer cover plate, and the plastic package body partially covers the sound input box, and the plurality of sound input holes are all located above the plastic package body.

8. The chip packaging structure according to claim 7, characterized in that: The height of a side surface of the plastic package body away from the substrate relative to the substrate is greater than or equal to the height of a side wall of the annular groove away from the substrate relative to the substrate, so that the plastic package body covers the annular groove.

9. The chip packaging structure according to claim 7, characterized in that: There are a plurality of annular grooves, which are arranged at intervals on the side walls around the sound inlet box, and each of the sound inlet holes is located above the plurality of annular grooves, and the plastic sealing body is coated on the plurality of annular grooves.

10. The chip packaging structure according to claim 7, characterized in that: A laser character groove is provided on a surface of the plastic package body away from the substrate, and a depth of the laser character groove is less than or equal to a distance between the surface of the plastic package body away from the substrate and the outer cover plate.

11. A method for preparing a chip packaging structure, characterized in that: Used to prepare the chip packaging structure according to any one of claims 1 to 10, the preparation method comprising: providing a substrate; Mounting a silicon microphone chip and a control chip on the substrate; Mounting a packaging cover plate on the substrate, wherein the packaging cover plate is arranged outside the silicon microphone chip and the control chip; Among them, the packaging cover plate includes an inner cover plate, an outer cover plate and a sound input box, the inner cover plate is arranged on the substrate and has a first sound cavity, the silicon microphone chip and the control chip are both accommodated in the first sound cavity, the outer cover plate is arranged outside the inner cover plate, and has a second sound cavity, the first sound cavity and the second sound cavity are connected, the sound input box is arranged on the outer cover plate and protrudes upward relative to the outer cover plate, and the sound input box has a sound input cavity connected to the second sound cavity, and a plurality of sound input holes are opened on the side walls around the sound input box, and the plurality of sound input holes are all connected to the sound input cavity.

12. The method for preparing a chip packaging structure according to claim 11, characterized in that: After the step of mounting the package cover on the substrate, the preparation method further comprises: forming a plastic package on the substrate; The plastic package body is coated on the outside of the outer cover plate and partially covers the sound inlet box, and the plurality of sound inlet holes are all located above the plastic package body.

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