CN102209287B - MEMS (micro electro mechanical system) microphone chip and manufacture method thereof - Google Patents

Abstract

The invention provides a MEMS microphone chip and a manufacturing method thereof, wherein the MEMS microphone chip includes a substrate and a parallel plate capacitor arranged on the substrate, one side of the parallel plate capacitor is opposite to the substrate, and the other side is externally provided with a protection device for use It is used to protect the main structure of the MEMS microphone chip. The invention separates the relatively fragile vibrating membrane and other structures in the parallel plate capacitor from the external space of the MEMS microphone chip by providing a protection device for the vibrating film, which can not only prevent the MEMS microphone chip from being polluted during the cutting process, but also effectively improve the manufacturing process. The efficiency of the process reduces the production cost and improves the yield of production; and it can also provide sufficient protection for the chip during the subsequent installation and use of the MEMS microphone chip.

Description

MEMS microphone chip and manufacturing method thereof

technical field

The invention relates to a microphone chip and a manufacturing method thereof, in particular to a MEMS microphone chip and a manufacturing and packaging method thereof.

Background technique

In recent years, with the continuous reduction in volume and higher performance of electronic products such as mobile phones and notebooks, correspondingly, the volume of supporting electronic components is continuously reduced, and the performance and consistency are improved, and the use of MEMS (micro-electromechanical systems) ) process-integrated MEMS microphones have begun to be applied in batches to electronic products such as mobile phones and notebooks. Against this backdrop, the demand for MEMS microphones produced using MEMS process technology is rapidly increasing. A core device of the MEMS microphone is the MEMS microphone chip made by MEMS technology, which can complete the sound-to-electricity conversion function.

Fig. 1 is the structure schematic diagram of existing a kind of MEMS microphone chip, as shown in Fig. 1, this MEMS microphone chip comprises a base 1, is provided with the hole 11 that penetrates up and down on the base 1, is provided with a fixed pole plate above the base 2. A parallel-plate capacitor composed of the isolation layer 3 and the vibrating film 4. The vibrating film 4 in the parallel-plate capacitor can receive external sound signals from above or below and vibrate, so that the parallel-plate capacitor generates an electrical signal to realize sound - Electric conversion function. A metal connection point 21 is arranged on the fixed pole plate 2, and a metal connection point 41 is arranged on the vibrating membrane 4, and the connection points 21 and 41 can lead out two electrodes of the parallel plate capacitor respectively.

Generally, this kind of chip is made by using MEMS technology on the wafer to make multiple MEMS chips, and then cut and disperse them into multiple independent MEMS chip units. Figure 2 is a schematic structural diagram of two MEMS chip units connected together before the MEMS microphone chip is cut. As shown in Figure 2, if cutting along the dotted line position, it can become two independent MEMS chip units. For ease of representation, only two MEMS chip units that have not been cut are used here to represent them. In actual production, a large number of MEMS chip units will be cut together. For MEMS chips with this structure, there are mainly two cutting processes, one is water cutting, which is relatively cheap, but the vibration film and other areas in the parallel plate capacitor are very fragile and are easily contaminated during the cutting process; Another cutting process is laser cutting. Laser cutting can avoid the problem of contamination of MEMS chips, but the cost is very high and it is not suitable for mass production.

Moreover, in the MEMS chip manufacturing process, the through-holes in the substrate need to be formed by an etching process, and the problem of the large thickness of the substrate also brings difficulties to the etching process, resulting in low etching efficiency and low yield of MEMS chips; in addition, MEMS In the chip manufacturing process, the substrate is also required to have a certain thickness to prevent the chip from being damaged or broken, which further increases the cutting cost of the MEMS chip unit and reduces the cutting efficiency.

Contents of the invention

In order to solve the above-mentioned problems in the prior art, the present invention provides a novel MEMS microphone chip and a method for manufacturing the MEMS microphone chip.

In order to achieve the above object, a MEMS microphone chip provided by the present invention includes a substrate and a parallel plate capacitor arranged on the substrate, one side of the parallel plate capacitor is opposite to the substrate, and a protection device is provided outside the other side for protecting MEMS. The main structure of the microphone chip.

In addition, the preferred structure is that the parallel plate capacitor includes a fixed pole plate, a vibrating film and an isolation layer arranged between the fixed pole plate and the vibrating film; and, the fixed pole plate and the vibrating film are respectively provided with the parallel The metal connection point where the two electrodes of the plate capacitor come out.

Furthermore, a preferred structure is that the protection device is installed on the vibrating membrane, and the metal connection points on the fixed pole plate and the vibrating membrane are both arranged outside the protection device.

Preferably, the protection device is a metal cap.

Preferably, the protection device includes an annular support ring and a flat plate fixed outside the annular support ring.

Preferably, the thickness of the substrate is in the range of 50-200 microns.

On the other hand, the present invention also provides a kind of manufacturing method of above-mentioned MEMS microphone chip, comprises the steps:

S1: Etching the wafer, and fabricating a MEMS microphone chip unit with a parallel plate capacitor on the substrate material layer;

S2: Fix the protection device outside the parallel plate capacitor.

Preferably, in step S1, further comprising:

The step of making the fixed polar plate with holes, the isolation layer and the vibrating membrane;

A step of setting metal connection points on the fixed pole plate and the vibrating membrane respectively.

Preferably, after step S2, it also includes:

S3: Grinding the substrate material layer to make it thinner, as the base of the MEMS microphone chip.

Preferably, after step S3, it also includes:

S4: setting through-holes on the substrate through an etching process;

S5: Cutting the wafer after the above steps S1-S4 to separate the MEMs microphone chip unit.

After adopting the above technologies, on the one hand, the setting of the protection device can separate the relatively fragile vibrating membrane and other structures in the parallel plate capacitor from the external space of the MEMS microphone chip, which not only effectively prevents the MEMS microphone chip from being damaged during the cutting process. Contamination can effectively improve the efficiency of the production process, reduce production costs, and increase production yield; and it can also provide sufficient protection for the chip during the subsequent installation and use of the MEMS microphone chip. On the other hand, the thinner substrate also makes the etching process for setting through holes and the cutting process for separating multiple MEMS microphone chip units easier, and diamond cutter wheels can be used for low-cost water cutting. From another perspective The production efficiency is improved, the cost is reduced, and the yield of the product is improved.

Description of drawings

Embodiments thereof are described below in conjunction with the accompanying drawings, and the above-mentioned features and technical advantages of the present invention will become clearer and easier to understand in conjunction with the accompanying drawings.

Fig. 1 is the schematic structural representation that represents a kind of existing MEMS microphone chip;

Fig. 2 is a schematic view showing the structure of an existing MEMS microphone chip before cutting;

Fig. 3 shows the structural representation of the MEMS microphone chip of the first embodiment of the present invention;

Fig. 4a-Fig. 4e represent the schematic diagram of the manufacturing process of the MEMS microphone chip of the first embodiment of the present invention;

Fig. 5 is the schematic diagram representing the manufacturing process of MEMS microphone chip of the present invention;

Fig. 6 shows the structural representation of the MEMS microphone chip of the second embodiment of the present invention;

FIG. 7 shows a schematic structural diagram of a MEMS microphone chip according to a third embodiment of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

(first embodiment)

FIG. 3 is a configuration diagram showing a MEMS microphone chip according to the first embodiment of the present invention. As shown in Figure 3, the MEMS microphone chip includes a base 1, the base 1 is provided with a hole 11 that penetrates up and down, and a parallel plate capacitor composed of a fixed plate 2, an isolation layer 3 and a vibrating membrane 4 is provided above the base, parallel The vibrating membrane 4 in the plate capacitor can receive external sound signals from above or below and vibrate, so that the parallel plate capacitor generates an electrical signal to realize the sound-to-electricity conversion function. A metal connection point 21 is arranged on the fixed pole plate 2, and a metal connection point 41 is arranged on the vibrating membrane 4, and the connection points 21 and 41 can lead out two electrodes of the parallel plate capacitor respectively. Moreover, a protection device 5 is provided on the side of the parallel plate capacitor opposite to the substrate 1 and above the vibrating membrane 4 . The setting of the protection device 5 separates the relatively fragile vibrating membrane and other structures in the parallel plate capacitor from the external space of the MEMS microphone chip, which can not only effectively prevent the MEMS microphone chip from being polluted during the cutting process, reduce production costs, and improve productivity; Moreover, it can also provide sufficient protection for the chip during the subsequent installation and use of the MEMS microphone chip.

In this embodiment, the protection device 5 is a metal cap, the open end of the metal cap is installed on the vibrating membrane 4, and the metal connection point 41 on the vibrating membrane 4 is arranged outside the metal cap.

4a-4e show schematic diagrams of the manufacturing process of the MEMS microphone chip of this embodiment.

Step 1: As shown in Figure 4a, Figure 4 shows a wafer that has not been etched or cut, and can be used to make multiple MEMS chip units, including substrate material layer 1', plate material layer 2', and isolation material layer 3' And the vibrating membrane material layer 4'.

Step 2: As shown in Figure 4b, etch the wafer shown in Figure 4a to produce a fixed pole plate 2 with holes, an isolation layer 3 and a vibrating membrane 4, and set them on the fixed pole plate 2 and the vibrating membrane 4 respectively The metal connection point 21 and the metal connection point 41 are used for connecting external circuits. Multiple MEMS microphone chip units can be fabricated on the wafer at the same time, here, represented by two MEMS microphone chip units.

Step 3: As shown in Fig. 4c, two protection devices 5 are respectively pasted and installed on the vibrating membrane 4 of the MEMS microphone chip unit, and the metal connection points 21 and 41 are arranged outside the protection device 5, which can be connected to an external circuit. In this embodiment, the protection device 5 is designed in the form of a metal cap.

Step 4: As shown in Fig. 4d, the substrate 1 is ground along the dotted line to reduce the thickness of the substrate material layer 1'. Because the protection device 5 can guarantee the strength of the MEMS microphone chip, the process of thinning the substrate material layer 1' can be realized, and the relatively thin substrate is easier to etch the substrate through-hole, and facilitates the cutting of the MEMS microphone chip unit. Before grinding, the thickness range of the substrate material layer 1' is generally 400-1200 microns, and after grinding, the thickness range is generally 50-200 microns.

Step 5: As shown in FIG. 4e, through-holes 11 are provided on the substrate 1 through an etching process, and the thinned substrate 1 is cut along the dotted line position to separate a plurality of MEMS microphone chip units, because the substrate material layer in the previous step The thickness of 1' becomes thinner, the etching process for setting the through hole 11 and the cutting process for separating multiple MEMS microphone chip units become easier, and the diamond cutter wheel can be used for low-cost water cutting, which improves the production from another angle Efficiency, reduced costs, and improved product yield.

It should be noted that the manufacturing process shown in the above steps is only a description of a specific embodiment of the present invention, and does not limit the present invention, and the specific operation of each step is not exclusive. For example, in step 1, depending on the structure of the MEMS microphone chip, there may be some differences in the content of each specific structural layer of the wafer; in step 2, according to the differences in the various structural layers of the wafer, the etched content may also be There are certain adjustments; in step 3, the protection devices can be set on the MEMS microphone chip one by one, or can be set in batches, for example: multiple protection devices are attached to the release paper and then set on the MEMS microphone chip together, Then remove the release paper, or you can use tape instead of the release paper.

Fig. 5 is the flow chart that the present invention makes MEMS microphone chip, as shown in Fig. 5, at first, wafer is etched, on substrate material layer, make the MEMS microphone chip unit (step S1) that has parallel plate capacitor; Then , the protection device is fixed on the outside of the parallel plate capacitor (step S2); on the basis of having the protection device to protect the parallel plate capacitor, the grinding substrate material layer makes it thinner, as the base of the MEMS microphone chip (step S3); then , setting through-holes on the substrate through an etching process (step S4); finally cutting the wafer after the above steps S1-S4 to separate the MEMS microphone chip unit (step S5).

Wherein, in step S1, further include the step of making fixed pole plate with holes, isolation layer and vibrating membrane; step.

The MEMS microphone chip of this structure of the present invention, because the protective device 5 that adopts is airtightly arranged on the vibrating membrane 4, the cavity that protecting device 5 and vibrating membrane 4 forms just becomes the acoustic cavity of MEMS chip, so be applicable to sound signal from MEMS chip The bottom enters and passes through the through hole 11 on the base 1 and the fixed pole plate 2, and finally acts on the product structure of the vibrating membrane 4.

(second embodiment)

FIG. 6 is a configuration diagram showing a MEMS microphone chip according to a second embodiment of the present invention. As shown in Figure 6, the MEMS microphone chip includes a base 1, the base 1 is provided with a hole 11 that penetrates up and down, and a parallel plate capacitor composed of a fixed plate 2, an isolation layer 3 and a vibrating membrane 4 is provided above the base, fixed A metal connection point 21 and a metal connection point 41 for leading out the two electrodes of the parallel plate capacitor are respectively arranged on the pole plate 2 and the vibrating membrane 4, and, on the side opposite to the substrate 1 of the parallel plate capacitor, the vibrating membrane 4 is provided with a protection device 5, which is used to separate the relatively fragile vibrating membrane and other structures in the parallel plate capacitor from the external space of the MEMS microphone chip, thereby preventing the MEMS microphone chip from being polluted during the cutting process, and the MEMS microphone Provide sufficient protection for the chip during subsequent installation and use of the chip.

Compared with the structure of the first embodiment, the difference of the MEMS microphone chip involved in this second embodiment is that the protective device 5 used is provided with a sound hole 51, and the sound signal can pass through the sound hole 51 from the outside of the protective device 5 Act on the vibrating membrane 4, so this product structure is suitable for two product structures in which the sound signal enters from above or below the MEMS chip.

(third embodiment)

FIG. 7 is a configuration diagram showing a MEMS microphone chip according to a third embodiment of the present invention. As shown in Figure 7, the MEMS microphone chip includes a base 1, the base 1 is provided with a hole 11 through up and down, and a parallel plate capacitor composed of a fixed plate 2, an isolation layer 3 and a vibrating membrane 4 is provided above the base, fixed A metal connection point 21 and a metal connection point 41 for leading out the two electrodes of the parallel plate capacitor are respectively arranged on the pole plate 2 and the vibrating membrane 4, and, on the side opposite to the substrate 1 of the parallel plate capacitor, the vibrating membrane 4, an annular support ring 52 and a flat plate 53 are arranged above. The annular support ring 52, the flat plate 53 and the diaphragm form a protective structure capable of sealing the diaphragm 4, which is used to separate structures such as the relatively fragile diaphragm in the parallel plate capacitor from the external space of the MEMS microphone chip, thereby avoiding The MEMS microphone chip is polluted during the cutting process, and sufficient protection is provided for the chip during the subsequent installation and use of the MEMS microphone chip.

Compared with the above-mentioned second embodiment, the main difference of the MEMS microphone chip involved in the third embodiment lies in the specific structure of the protection device. In this embodiment, the protection device is composed of two parts, namely an annular support ring 52 and a flat plate 53 fixed on the support ring. The annular support ring 52 is produced on the MEMS microphone chip by semiconductor technology, and the flat plate 53 is additionally bonded and mounted.

In the above embodiments, a partial structure of a capacitive component of a MEMS microphone chip is exemplified, but the present invention does not limit its specific form.

Although the specific implementation of the present invention is described above for the specific structure of the MEMS microphone chip, under the above teaching of the present invention, those skilled in the art can make various improvements and modifications on the basis of the above implementation. Those skilled in the art should understand that the above specific description is only for the purpose of explaining the present invention, and is not intended to limit the present invention. The protection scope of the present invention is defined by the claims and their equivalents.

Claims (6)

1. a kind of MEMS microphone chip, comprise substrate (1) and be arranged on the parallel plate capacitor on the substrate, it is characterized in that, described MEMS microphone chip also comprises: A protection device (5) is arranged outside the parallel plate capacitor, and the protection device (5) is a metal cap; The parallel plate capacitor comprises a fixed pole plate (2), a vibrating membrane (4) and an isolation layer (3) arranged between the fixed pole plate and the vibrating membrane; The base (1) is provided with a hole (11) that penetrates up and down; The fixed pole plate (2) and the vibrating membrane (4) are respectively provided with metal connection points leading out the two electrodes of the parallel plate capacitor; The protective device (5) is installed on the vibrating membrane (4), and the metal connection points on the fixed pole plate and the vibrating membrane are all arranged outside the protective device; The protective device (5) is provided with a sound hole (51), and the MEMS microphone chip is suitable for two product structures in which sound signals enter from above or below the MEMS chip. 2. according to the MEMS microphone chip according to claim 1, it is characterized in that, The protection device (5) includes an annular support ring (52) and a flat plate (53) fixed outside the annular support ring (52). 3. according to the MEMS microphone chip according to claim 1, it is characterized in that, The thickness of the substrate is in the range of 50-200 microns. 4. the method for manufacturing the MEMS microphone chip described in any one of claims 1 to 3, is characterized in that, S1: Etching the wafer, and fabricating a MEMS microphone chip unit with a parallel plate capacitor on the substrate material layer; S2: fixing a protective device provided with a sound hole on the outside of the parallel plate capacitor; S3: Grinding the substrate material layer to make it thinner, as the base of the MEMS microphone chip; S4: setting through-holes on the substrate through an etching process; The MEMS microphone chip is suitable for two product structures in which sound signals enter from above or below the MEMS chip. 5. according to the manufacturing method of MEMS microphone chip according to claim 4, it is characterized in that, in step S1, further comprising: The step of making the fixed polar plate with holes, the isolation layer and the vibrating membrane; A step of setting metal connection points on the fixed pole plate and the vibrating membrane respectively. 6. according to the manufacturing method of MEMS microphone chip according to claim 4, it is characterized in that, after step S4, also comprise: S5: cutting the wafer after the above steps of S1 to S4 to separate the MEMS microphone chip unit.