JP7056853B2 - Mounting structure of MEMS element - Google Patents

Description

The present invention relates to a mounting structure of a MEMS device .

For example, in a microphone device using a MEMS element, as shown in FIG. 5, electronic components such as a MEMS element 2 and an integrated circuit 3 for processing a signal output from the MEMS element 2 are mounted on a mounting substrate 1 and the whole is mounted. Is covered with a metal lid 4. In the example shown in FIG. 5, a hole 5 is formed in the lid 4 so that sound pressure or the like propagates to the MEMS element 2. The surface of the integrated circuit 3 is covered with a resin 6 to protect it. The hole 5 may be provided in the mounting substrate 1 so as to communicate with the back chamber of the MEMS element 2 instead of being provided in the lid 4.

FIG. 6 is an enlarged view of a part of the MEMS element 2 shown in FIG. In the MEMS element 2, a movable electrode film 9 including a movable electrode is laminated on a handle substrate 7 via an insulating film 8, and a fixed electrode film 11 including a fixed electrode is further laminated and formed via a spacer 10. Note that in FIG. 6, the connection with the integrated circuit 3 and the like are not shown. This type of MEMS device is described in, for example, Patent Document 1.

By the way, as shown in FIG. 6, in the assembly process in which the integrated circuit 3 is mounted on the mounting board 1 or the lid 4 is mounted after the handle board 7 is bonded to the mounting board 1 by the adhesive member 12, the temperature is 100 ° C. Heat treatment may be performed to exceed the limit. At that time, since the back chamber 13 having a large opening is formed in the handle substrate 7, the force in the arrow direction shown in FIG. 6 due to the difference in the physical properties of thermal expansion and contraction between the mounting substrate 1 and the handle substrate 7. A force in the opposite direction is applied to the handle substrate 7, which may cause characteristic fluctuation or damage.

Therefore, in order to reduce the force applied to the handle substrate 7, it is conceivable to reduce the joint area between the mounting substrate 1 and the handle substrate 7. However, there are difficulties in controlling the coating amount and coating position of the adhesive member 12, the difficulty in aligning the adhesive member 12 and the handle substrate 7, and the like, and the mounting substrate 1 and the handle substrate 7 are joined by the adhesive member 12. In some cases, there will be areas that are not used. This unjoined region becomes a passage through which sound pressure or the like leaks, which causes a new problem that the sensitivity is lowered.

Further, if the coating amount of the adhesive member 12 is too large, the adhesive member 12 crawls up the handle substrate 7, or if the hole 5 is formed in the mounting substrate 1, the adhesive member 12 is formed in the hole 5. Will flow out and other problems will occur. Such a problem has become a big problem as the MEMS element becomes smaller and shorter.

Japanese Unexamined Patent Publication No. 2011-55087

In the conventional mounting structure of the MEMS element, when the bonding area between the mounting board 1 and the handle board 7 becomes wide, a force is applied to the handle board 7 due to thermal expansion and contraction of the mounting board 1, which causes problems such as fluctuation of the characteristics of the MEMS element. there were. On the other hand, if the bonding area is reduced to avoid the influence thereof, the coating amount of the adhesive member 12 must be controlled, but if the coating amount cannot be controlled and the adhesive member 12 is reduced, the mounting substrate 1 and the handle substrate are reduced. There are problems that the bonding area with 7 is small and sufficient bonding strength cannot be maintained, or a region that is not bonded is generated and the sensitivity of the MEMS element is significantly lowered. On the other hand, if there are too many adhesive members 12, they may crawl up to the handle substrate 7, which hinders the miniaturization and lowering of the height of the MEMS element. An object of the present invention is to solve these problems and to provide a mounting structure of a MEMS device capable of forming a reliable junction without increasing the junction area.

In order to achieve the above object, the mounting structure of the MEMS element according to claim 1 of the present application includes a handle substrate provided with a back chamber, a fixed electrode film including a fixed electrode and a movable electrode with a spacer sandwiched on the handle substrate. A notch portion in which at least a part of the outer peripheral side of the handle substrate is cut out from the joint surface of the handle substrate with the mounting substrate, and at least the back chamber of the handle substrate are arranged so as to face each other. It is a mounting structure of a MEMS element in which a MEMS element having a convex portion remaining on the side is mounted on a mounting substrate, and the mounting substrate is provided with a concave portion on a joint surface with the MEMS element and is provided at the bottom of the concave portion. It is characterized in that the convex portion of the MEMS element abuts and the bottom portion of the concave portion and the notch portion are joined by an adhesive member so that the MEMS element is joined onto the substrate .

The mounting structure of the MEMS element according to claim 2 of the present application is the mounting structure of the MEMS element according to claim 1, wherein the concave portion of the mounting substrate has a concave portion having a bottom portion with which the convex portion of the MEMS element abuts, and the above-mentioned concave portion. It is characterized in that the notch portion of the MEMS element and the recess having the bottom portion facing each other are separated from each other.

The mounting structure of the MEMS element according to claim 3 of the present application is characterized in that, in the mounting structure of the MEMS element according to any one of claims 1 or 2 , the handle substrate and the mounting substrate are respectively made of silicon .

The mounting structure of the MEMS element of the present invention is such that the bottom of the recess provided in the mounting substrate and the notch of the MEMS element are joined by an adhesive member to ensure that the MEMS element is mounted on the mounting substrate. By adhering and contacting the convex portion of the handle substrate with the mounting substrate, the joining area can be limited and the adhesive member can be prevented from entering the inside of the convex portion.

Further, when the concave portion formed on the mounting substrate is configured to be separated into a concave portion having a bottom portion with which the convex portion of the MEMS element abuts and a concave portion having a bottom portion facing the notch portion of the MEMS element, the separated concave portions are separated. The structure is such that the convex portion is arranged on the surface, so that the adhesive member does not enter the convex portion of the MEMS element, the mounting substrate, and the contact portion, and the bonding is applied between the notch portion of the MEMS element and the bottom portion of the concave portion of the mounting substrate. There is an advantage that the amount of members can be easily controlled.

By forming the handle substrate and the mounting substrate of the MEMS element of the present invention with the same material, particularly silicon, the force applied to the handle substrate due to the difference in the physical properties of thermal expansion and contraction is reduced, and the characteristics of the MEMS element are stabilized. In addition, there is an advantage that it can be easily formed according to the manufacturing method of the semiconductor device.

It is a figure explaining the MEMS element of the 1st Embodiment of this invention. It is a figure explaining the mounting structure of the MEMS element of the 2nd Embodiment of this invention. It is a figure explaining the mounting structure of the MEMS element of the 3rd Embodiment of this invention. It is a figure explaining the mounting structure of the MEMS element of another Example of this invention. It is explanatory drawing of the general microphone apparatus. It is an enlarged view of the MEMS element of the microphone apparatus shown in FIG.

The mounting structure of the MEMS element of the present invention is such that the bottom of the recess provided in the mounting substrate and the notch of the MEMS element are joined by an adhesive member to ensure that the MEMS element is mounted on the mounting substrate. At the same time as adhering, the convex portion of the handle substrate abuts on the mounting substrate, thereby limiting the joining area and preventing the adhesive member from entering the inside of the convex portion. Hereinafter, examples of the present invention will be described in detail according to the manufacturing process.

First, the MEMS device of the present invention will be described. FIG. 1 is an explanatory diagram of the MEMS element 2 of the first embodiment. Similar to the conventional MEMS element, for example, a movable electrode film 9 including a movable electrode and a fixed electrode film 11 including a fixed electrode are arranged facing each other on a handle substrate 7 made of a silicon substrate via an insulating film 8. ing. A back chamber 13 is formed on the handle substrate 7.

The MEMS element 2 of this embodiment has a joint surface with a mounting substrate, which will be described later, which is different from that of a general MEMS element. Specifically, as shown in FIG. 1, a notch portion 14 is formed on the outer peripheral side of the handle substrate 7, and the notch portion 14 is not formed on the back chamber 13 side of the handle substrate 7, and the convex portion 15 is formed. The structure is such that the back chamber 13 does not communicate with the back chamber 13.

For example, even if the notch portion 14 has a structure in which the outer peripheral side of the handle substrate 7 is completely cut out so that the convex portion 15 remains along the back chamber 13, a part of the convex portion 15 extends to the outer peripheral side of the handle substrate 7. The structure may be such that a plurality of notches 14 partitioned by the convex portions 15 are arranged around the back chamber 13.

Here, the convex portion 15 is not limited to a relatively narrow shape along the back chamber 13 shown in FIG. However, as will be described later, since the adhesive member with the mounting substrate is formed at the position of the notch portion 14, it is necessary to secure the area of the notch portion 14 so that sufficient adhesive strength can be obtained. Further, since the convex portion 15 abuts on the mounting board to determine the mounting posture so as to be horizontally arranged at a desired position and height on the mounting board, it is necessary to set the convex portion 15 to a desired size. .. It is also necessary to form the convex portion 15 so as to have a flatness such that no gap is formed when the convex portion 15 comes into contact with the surface of the mounting substrate.

Next, an example relating to the mounting structure for joining the MEMS element described in the first embodiment to the mounting substrate will be described. FIG. 2 is an explanatory diagram of the mounting structure of the MEMS element of the present invention. As shown in FIG. 2, the mounting substrate 1 of the present invention has a structure in which a recess 16 is provided at a joint portion with the MEMS element 2. When the MEMS element 2 is mounted on the mounting substrate 1 having such a structure, the convex portion 15 of the MEMS element 2 abuts on the bottom of the concave portion 16 of the mounting substrate 1, and the notch portion 14 of the MEMS element 2 and the mounting substrate 1 A gap is formed with the bottom of the recess 16. In the mounting structure of the present invention, the adhesive member 12 is inserted into this gap to join the MEMS element 2 and the mounting substrate 1.

When joining the MEMS element 2 and the mounting substrate 1, a predetermined amount of the adhesive member 12 may be applied to the recess 16 and the MEMS element 2 may be placed. If the desired adhesive strength is obtained, it is not necessary to completely fill the gap formed between the notch 14 of the MEMS element 2 and the bottom of the recess 16 of the mounting substrate 1 as shown in FIG. ..

On the other hand, when the adhesive member 12 is completely filled in the gap between the notch 14 and the bottom of the recess 16, the convex portion 15 is in contact with the bottom of the recess 16 without a gap, so that the adhesive member 12 is further inward. It doesn't get in.

Therefore, by adopting the MEMS element of the present invention as the mounting structure of the present invention, it is possible to limit the region where the adhesive member 12 is formed to a predetermined range, and the thermal expansion and contraction of the mounting substrate and the handle substrate can be caused. The difference makes it possible to suppress fluctuations in the characteristics of the MEMS element. In particular, if the mounting substrate is made of a silicon substrate made of the same material as the handle substrate, it is possible to further suppress fluctuations in characteristics.

Next, an embodiment relating to another mounting structure for joining the MEMS element described in the first embodiment to the mounting substrate will be described. FIG. 3 is an explanatory diagram of another mounting structure of the MEMS element of the present invention. As shown in FIG. 3, the mounting substrate of the present invention has a structure in which two recesses 16a and 16b are provided at a joint portion with the MEMS element. The mounting board 1 remaining between the concave portions 16a and the concave portions 16b is a convex portion 17. When the MEMS element 2 is mounted on the mounting substrate 1 having such a structure, the convex portion 15 of the MEMS element 2 abuts on the bottom of the concave portion 16a of the mounting substrate 1, and the convex portion 17 of the mounting substrate 1 cuts the MEMS element 2. It abuts on the notch 14, and a gap is formed between the notch 14 of the MEMS element 2 and the bottom of the recess 16b of the mounting substrate 1. In the mounting structure of the present invention, the adhesive member 12 enters the gap, and the MEMS element 2 and the mounting substrate 1 are joined to each other.

When joining the MEMS element 2 and the mounting substrate 1, a predetermined amount of the adhesive member 12 may be applied to the recess 16b and the MEMS element 2 may be placed. If the desired bonding strength is obtained, it is not necessary to completely fill the gap formed between the notch 14 of the MEMS element 2 and the bottom of the recess 16b of the mounting substrate 1 as shown in FIG. ..

On the other hand, when the adhesive member 12 is completely filled in the gap between the notch 14 and the bottom of the recess 16b, the convex portion 17 is in contact with the notch 14 without a gap, and the convex portion 15 of the MEMS element 2 is recessed. Since it is in close contact with the bottom of 16a, the adhesive member 12 does not further enter the inside.

Therefore, by adopting the MEMS element of the present invention as the mounting structure of the present invention, it is possible to limit the region where the adhesive member 12 is formed to a predetermined range, and the thermal expansion and contraction between the mounting substrate and the handle substrate can be performed. It is possible to suppress fluctuations in the characteristics of the MEMS element due to the difference in the above. In particular, if the mounting substrate is made of a silicon substrate made of the same material as the handle substrate, it is possible to further suppress fluctuations in characteristics.

In the above embodiment, the hole 5 may be formed in the mounting substrate 1. For example, FIG. 4 shows a case where the mounting structure of the structure described in the second embodiment is mounted on the mounting board 1 provided with the hole 5 of the board 1. The same applies to the case where the hole 5 is formed in the mounting substrate 1 described with reference to FIG.

In the mounting structure described above, when forming the lid portion, a part of the silicon substrate is cut out, and the cutout portion is covered with the lid portion 4 so that electronic components such as the MEMS element 2 and the integrated circuit 3 are accommodated. As for the structure, when the handle substrate 7 and the mounting substrate 1 are each made of a silicon substrate, the influence of thermal expansion and contraction is reduced, which is preferable.

As described above, according to the present invention, the MEMS element and the mounting substrate have been described, but it goes without saying that the present invention is not limited to these examples. For example, the arrangement of the notch portion 14, the convex portion 15, the concave portions 16, 16a, 16b, and the convex portion 17 may be appropriately set. Further, the adhesive member 12 can also be appropriately selected.

1: Mounting board 2: MEMS element 3: Integrated circuit 4: Lid part 5: Hole part, 6: Resin, 7: Handle board, 8: Insulation film, 9: Movable electrode film, 10: Spacer, 11 : Fixed electrode film, 12: Adhesive member, 13: Back chamber, 14: Notch, 15: Convex, 16, 16a, 16b: Concave, 17: Convex

Claims (3)

A handle substrate provided with a back chamber, a fixed electrode film including a fixed electrode and a movable electrode film including a movable electrode are arranged to face each other on the handle substrate with a spacer interposed therebetween, and a bonding surface with the mounting substrate of the handle substrate. In addition, a MEMS element having a notch portion in which at least a part of the outer peripheral side of the handle substrate is cut out and a convex portion remaining on the back chamber side of the handle substrate is mounted on the mounting substrate. It is a mounting structure of the element,
The mounting substrate has a recess on the joint surface with the MEMS element.
The convex portion of the MEMS element is in contact with the bottom portion of the concave portion, and the bottom portion of the concave portion and the notch portion are bonded by an adhesive member so that the MEMS element is bonded on the substrate. The mounting structure of the MEMS element . In the mounting structure of the MEMS element according to claim 1, the concave portion of the mounting substrate has a concave portion having a bottom portion with which the convex portion of the MEMS element abuts, and the bottom portion facing the notch portion of the MEMS element. A mounting structure for a MEMS element, characterized in that the recesses are separated from each other . The mounting structure of a MEMS element according to any one of claims 1 or 2 , wherein the handle substrate and the mounting substrate are each made of silicon .

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