TWI844967B - Micro-electromechanical packaging structure - Google Patents

Abstract

A micro-electromechanical packaging structure including a substrate, a sensing module, a water-proof layer, and a cover is provided. The substrate has a first surface, a second surface, and an acoustic hole penetrating the first surface and the second surface. The acoustic hole has an upper opening and a lower opening, and an aperture of the lower opening is larger than an aperture of the upper opening. The sensing module is disposed on the first surface of the substrate and covers the upper opening. The water-proof layer is disposed on the second surface of the substrate and covers the lower opening. The water-proof layer has a plurality of fine holes. The fine holes are communicated with the acoustic hole. The cover is disposed on the first surface and covers the sensing module.

Description

MEMS Package Structure

The present invention relates to a micro-electromechanical system component, and more particularly to a micro-electromechanical system package structure.

A MEMS microphone consists of a diaphragm and a back plate, which are made on a silicon chip to receive sound waves and convert them into electrical signals. MEMS microphones have been widely used in laptops, smart phones and various portable electronic products. In recent years, the dustproof and waterproof functions of portable electronic products have also begun to receive attention.

In order to prevent water droplets from entering the sound hole and causing damage to the sound receiving module, existing MEMS microphones need to form multiple fine holes on the substrate corresponding to the sound receiving module. These fine holes can prevent water droplets from entering the MEMS microphone. However, because the aperture of the fine holes is too small, the energy loss when the sound wave is transmitted to the sensing module is increased, thereby affecting the sound receiving performance of the MEMS microphone.

The present invention provides a micro-electromechanical system packaging structure suitable for a micro-electromechanical system microphone. Sound holes with different diameters are formed on a substrate. The side with a larger diameter can accommodate more small holes, thereby reducing the energy loss when the sound wave is transmitted to the sensing module, so as to maintain the sound receiving performance of the micro-electromechanical system microphone.

The micro-electromechanical system package structure of the present invention includes a substrate, a sensing module, a waterproof layer and a cover. The substrate has a first surface, a second surface and a sound hole penetrating the first surface and the second surface. The sound hole has an upper opening and a lower opening, and the diameter of the lower opening is larger than the diameter of the upper opening. The sensing module is arranged on the first surface of the substrate and covers the upper opening. The waterproof layer is arranged on the second surface of the substrate and covers the lower opening. The waterproof layer has a plurality of fine holes. The plurality of fine holes are connected to the sound hole. The cover is arranged on the first surface and covers the sensing module.

In one embodiment of the present invention, the plurality of fine holes are distributed within the area of the vertical projection of the lower opening and beyond the area of the vertical projection of the upper opening.

In one embodiment of the present invention, the sound hole has a stepped side surface extending vertically from the first surface to the second surface.

In one embodiment of the present invention, the sound hole has an inclined side surface extending obliquely from the first surface to the second surface.

In an embodiment of the present invention, the upper opening of the sound hole extends vertically from the first surface by a first thickness, and the sound hole extends obliquely from the first thickness by a second thickness to the second surface to form a lower opening.

In one embodiment of the present invention, the sensing module has a chamber corresponding to the sound hole, and an inner diameter of the chamber matches the diameter of the upper opening of the sound hole.

In one embodiment of the present invention, the distance between the upper opening and the lower opening is greater than 50um, and in a preferred embodiment, it is between 50um and 75um.

In one embodiment of the present invention, the diameter of each of the pores is between 20um and 50um, and in a preferred embodiment, it is between 34um and 42um. The number of the pores is more than 8, and in a preferred embodiment, it is 31 to 48.

In an embodiment of the present invention, the sensing module further comprises at least one electrode, and the electrode is disposed on an outer surface of the waterproof layer away from the substrate.

In an embodiment of the present invention, the sensing module further includes at least one electrode, and the electrode is disposed on a top surface of the cover.

In one embodiment of the present invention, a heightening layer is further included, which is disposed outside the waterproof layer and has an opening corresponding to and connecting the plurality of fine holes.

Based on the above, the MEMS packaging structure of the present invention is suitable for MEMS microphones. Sound holes with different diameters are formed on the substrate. At the same time, a waterproof layer is configured on the substrate. The waterproof layer has multiple fine holes and is located opposite to the sound holes. The sound waves in the environment are transmitted from the fine holes through the sound holes to the sensing module in sequence. The side with a larger diameter of the sound hole corresponds to multiple fine holes to increase the number of fine holes in the waterproof layer within the range of the sound hole. The side with a smaller diameter of the sound hole corresponds to the connected sensing module so that the first surface of the substrate has enough space to carry the sensing module. The MEMS microphone can reduce the energy loss when the sound wave is transmitted to the sensing module by increasing the number of fine holes without increasing the overall volume, so as to maintain the sound reception performance of the MEMS microphone.

In addition, the multiple fine holes in the waterproof layer can effectively prevent water droplets from entering the sound hole and causing damage to the sensor module.

Fig. 1 is a schematic plan view of a MEMS package structure of the first embodiment of the present invention. Fig. 2 is a schematic plan view of a sound hole and a plurality of fine holes of the MEMS package structure of Fig. 1. Fig. 3 is a schematic plan view of the MEMS package structure of Fig. 1 combined with a heightening layer.

Referring to FIG. 1 , the MEMS package structure of the present invention is applicable to a MEMS microphone, and is formed by a substrate, a sensing module, an application-specific integrated circuit (ASIC), and a housing package. The substrate is, for example, a circuit board and has a metal line, and the sensing module and the application-specific integrated circuit are electrically coupled to the metal line of the substrate. In addition, the application-specific integrated circuit and the sensing module are coupled to each other through wire bonding.

1 , the MEMS package structure 100 of this embodiment includes a substrate 110 , a sensing module 120 , a waterproof layer 130 , and a cover 140 .

The substrate 110 has a first surface 111, a second surface 112 and a sound hole 113 penetrating the first surface 111 and the second surface 112. The sound hole 113 has an upper opening 1131 and a lower opening 1132, and the diameter D2 of the lower opening 1132 is larger than the diameter D1 of the upper opening 1131, wherein the sound hole 113 is used to transmit sound waves W in the environment.

Furthermore, the sound hole 113 has a stepped side surface 1133 extending vertically from the first surface 111 to the second surface 112, and the distance between the upper opening 1131 and the lower opening 1132 is greater than 50um, and is between 50um and 75um in a preferred embodiment. The diameter D1 of the sound hole 113 extends vertically from the first surface 111 to between 25um and 37.5um, and the diameter D2 of the sound hole 113 extends vertically from 25um to 37.5um to the second surface 112 to form the stepped side surface 1133.

The sensing module 120 is disposed on the first surface 111 of the substrate 110 and covers the upper opening 1131 of the sound hole 113. The sensing module 120 is a microphone sensor and has a chamber 121 and a diaphragm 122. The chamber 121 is connected to the sound hole 113, and the size and shape of an inner diameter of the chamber 121 match the diameter D1 of the upper opening 1131 of the sound hole 113.

In addition, when the sound wave W enters the chamber 121 through the sound hole 113, the sound wave W generates a pressure difference in the chamber 121 to cause the diaphragm 122 to vibrate. The diaphragm 122 converts the vibration into an electronic signal, and then transmits the electronic signal to the specific application integrated circuit and the speaker in sequence to output audio.

Referring to FIG. 1 and FIG. 2 , the waterproof layer 130 is disposed on the second surface 112 of the substrate 110 and covers the lower opening 1132 of the sound hole 113. The waterproof layer 130 has a plurality of fine holes 131. The plurality of fine holes 131 are connected to the sound hole 113 and are distributed within the range of the lower opening 1132. Specifically, the plurality of fine holes 131 are distributed within the area of the vertical projection of the lower opening 1132 and exceed the area of the vertical projection of the upper opening 1131, wherein the plurality of fine holes 131 are evenly distributed within the area of the lower opening 1132. The cover 140 is disposed on the first surface 111 and covers the sensing module 120.

Referring to FIG. 2 , in this embodiment, the diameter of each pore 131 is between 20um and 50um, and in a preferred embodiment, between 34um and 42um, and the number of the plurality of pores 131 is 31 to 48. In this embodiment, the diameter of the pore 131 needs to be less than or equal to 42um to meet the waterproof standard and not cause excessive acoustic wave damping, but the diameter of the pore 131 cannot be less than 34um. If the diameter of the pore 131 is less than 34um, the energy loss of the acoustic wave when passing through each pore 131 will increase, which is not conducive to acoustic wave sensing of the sensing module 120. The number of the plurality of fine holes 131 is adjusted to 31 to 48 according to the size of the diameter D2 of the lower opening 1132 , and is evenly distributed in the area of the lower opening 1132 .

For example, when the diameter D2 of the lower opening 1132 of the sound hole 113 is 800 um, the number of the fine holes 131 is 31, and when the diameter D2 of the lower opening 1132 of the sound hole 113 is 1000 mm, the number of the fine holes 131 is 48.

In other embodiments, the number of fine holes may be less than 31 or greater than 48, depending on the size of the sound hole. The present invention does not limit the number of fine holes.

1 , the sensing module 120 includes at least one electrode 123 . In this embodiment, there are multiple at least one electrode 123 , and the multiple electrodes 123 are disposed on an outer surface 132 of the waterproof layer 130 away from the substrate 110 .

In addition, the plurality of electrodes 123 are coupled to a motherboard of a computer, a laptop or a smart phone to supply power to the sensing module 120.

Referring to FIG. 3 , the MEMS package structure 100A of this embodiment further includes a heightened layer 150a, which is disposed outside the waterproof layer 130a and has an opening 151a corresponding to and connected to the plurality of fine holes 131a. The heightened layer 150a is used to support the waterproof layer 130a, thereby preventing the waterproof layer 130a from directly contacting the motherboard or other components, thereby causing damage to the plurality of fine holes 131a of the waterproof layer 130a. In addition, the plurality of electrodes 123a of the sensing module 120a are disposed on a side of the heightened layer 150a away from the waterproof layer 130a.

Referring to FIG. 4 , the MEMS package structure 100B of this embodiment is different from the MEMS package structure 100 shown in FIG. 1 in that the sound hole 113b has an inclined side surface 1133b extending obliquely from the first surface 111b to the second surface 112b. Specifically, the width of the inclined side surface 1133b of the sound hole 113b gradually increases from the upper opening 1131b toward the lower opening 1132b, so that the second surface of the substrate retains sufficient opening space while the first surface of the substrate also has sufficient carrying space. When the sound wave W enters the sound hole 113b from the lower opening 1132b, it will pass through the upper opening 1131b along the inclined side surface 1133b with a gradually decreasing width and enter the cavity 121b of the sensing module 120b.

Referring to FIG. 5 , the MEMS package structure 100C of the present embodiment is different from the MEMS package structure 100 shown in FIG. 1 in that the upper opening 1131c of the acoustic hole 113c extends vertically from the first surface 111c by a first thickness T1, and the acoustic hole 113c extends obliquely from the first thickness T1 by a second thickness T2 to the second surface 112c to form a lower opening 1132c. Specifically, the inner diameter of the chamber 121c matches the diameter D1 of the upper opening 1131c of the acoustic hole 113c, and the width of the acoustic hole 113c gradually increases from the first thickness T1 toward the lower opening 1132c, so that the second surface of the substrate retains sufficient opening space while the first surface of the substrate also has sufficient carrying space.

Referring to FIG. 6 , the MEMS package structure 100D of this embodiment is different from the MEMS package structure 100 shown in FIG. 1 in that the sensing module 120d includes at least one electrode 123d. There are multiple electrodes 123d, and the multiple electrodes 123d are disposed on a top surface of the cover 140d. In addition, the multiple electrodes 123d are used to couple to a motherboard of a computer, a laptop or a smart phone to supply power to the sensing module 120d.

In summary, the MEMS packaging structure of the present invention is suitable for MEMS microphones. Sound holes with different diameters are formed on a substrate. A waterproof layer is disposed on the substrate at the same time. The waterproof layer has a plurality of fine holes and is located opposite to the sound holes. Sound waves in the environment are transmitted from the fine holes through the sound holes in sequence to the sensing module. The side with a larger diameter of the sound hole corresponds to a plurality of fine holes to increase the number of fine holes of the waterproof layer within the range of the sound hole. The side with a smaller diameter of the sound hole corresponds to the connected sensing module so that the first surface of the substrate has sufficient space to carry the sensing module. The MEMS microphone can reduce the energy loss when the sound wave is transmitted to the sensing module by increasing the number of fine holes without increasing the overall volume, so as to maintain the sound reception performance of the MEMS microphone.

In addition, the multiple fine holes in the waterproof layer can effectively prevent water droplets from entering the sound hole and causing damage to the sensor module.

100, 100A, 100B, 100C, 100D: MEMS package structure 110: substrate 111, 111b: first surface 112, 112b: second surface 113, 113b, 113c: sound hole 1131, 1131c: upper opening 1132, 1132c: lower opening 1133, 1133b: side surface 120, 120a, 120b, 120d: sensing module 121, 121b: chamber 122: diaphragm 123, 123a, 123d: electrode 130, 130a: waterproof layer 131, 131a: fine hole 132: outer surface 140, 140d: cover 150a: heightening layer 151a: opening W: sound wave D1, D2: caliber T1: first thickness T2: second thickness

FIG. 1 is a schematic plan view of a microelectromechanical package structure of the first embodiment of the present invention. FIG. 2 is a schematic plan view of a sound hole and a plurality of fine holes of the microelectromechanical package structure of FIG. 1. FIG. 3 is a schematic plan view of the microelectromechanical package structure of FIG. 1 combined with an enhancement layer. FIG. 4 is a schematic plan view of a microelectromechanical package structure of the second embodiment of the present invention. FIG. 5 is a schematic plan view of a microelectromechanical package structure of the third embodiment of the present invention. FIG. 6 is a schematic plan view of a microelectromechanical package structure of the fourth embodiment of the present invention.

100:Micro-electromechanical packaging structure

110: Substrate

111: First surface

112: Second surface

113: Sound hole

1131: Upper opening

1132: Lower opening

1133: Side

120:Sensor module

121: Chamber

122: Diaphragm

123:Electrode

130: Waterproof layer

131: Fine holes

132: External surface

140: Cover

W: Sound waves

D1, D2: caliber

Claims (10)

A micro-electromechanical package structure includes: a substrate having a first surface, a second surface, and a sound hole penetrating the first surface and the second surface, wherein the sound hole has an upper opening and a lower opening, and the diameter of the lower opening is larger than the diameter of the upper opening; a sensing module, arranged on the first surface of the substrate and covering the upper opening; a waterproof layer, arranged on the second surface of the substrate and covering the lower opening, wherein the waterproof layer has a plurality of fine holes, and the fine holes are connected to the sound hole; and a cover, arranged on the first surface and covering the sensing module, wherein the fine holes are distributed within the area of the vertical projection of the lower opening and beyond the area of the vertical projection of the upper opening. A micro-electromechanical package structure as described in claim 1, wherein the acoustic hole has a stepped side surface extending vertically from the first surface to the second surface. A micro-electromechanical package structure as described in claim 1, wherein the sound hole has an inclined side surface extending obliquely from the first surface to the second surface. The micro-electromechanical package structure as described in claim 1, wherein the upper opening of the sound hole extends vertically from the first surface to a first thickness, and the sound hole extends obliquely from the first thickness to the second surface to form the lower opening. The micro-electromechanical package structure as described in claim 1, wherein the sensing module has a chamber corresponding to the sound hole, and an inner diameter of the chamber matches the diameter of the upper opening of the sound hole. A micro-electromechanical package structure as described in claim 1, wherein the distance between the upper opening and the lower opening is between 50um and 75um. The micro-electromechanical system package structure as described in claim 1, wherein the diameter of each of the fine holes is between 34um and 42um, and the number of the fine holes is between 31 and 48. The micro-electromechanical system package structure as described in claim 1, wherein the sensing module further includes at least one electrode, and the electrode is disposed on an outer surface of the waterproof layer away from the substrate. The micro-electromechanical package structure as described in claim 1, wherein the sensing module further includes at least one electrode, and the electrode is disposed on a top surface of the cover. The MEMS package structure as described in claim 1 also includes a heightening layer disposed outside the waterproof layer and having an opening corresponding to and connected to the fine holes.

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