WO2016042937A1

WO2016042937A1 - Pressure sensor module

Info

Publication number: WO2016042937A1
Application number: PCT/JP2015/072210
Authority: WO
Inventors: 征克森
Original assignee: 株式会社村田製作所
Priority date: 2014-09-19
Filing date: 2015-08-05
Publication date: 2016-03-24
Also published as: DE112015004268T5; CN106716095A

Abstract

The present invention pertains to a pressure sensor module which is characterized by being provided with: a circuit board having a wiring conductor; an integrated circuit element disposed on a first surface of the circuit board and electrically connected to the wiring conductor; a pressure sensor element disposed on the first surface side of the circuit board and electrically connected to the integrated circuit element; and a lid body disposed on the first surface side of the circuit board to cover the integrated circuit element and the pressure sensor element and adhered to the circuit board. The pressure sensor module is further characterized in that the lid body has a through-hole communicating with the outer space and the inner space of the lid body such that a straight line connecting the outer space to the inner space through the inside of the through-hole without passing through the lid body exists, and such that a straight line connecting the outer space to the integrated circuit element through the inside of the through-hole without passing through the lid body does not exist.

Description

Pressure sensor module

The present invention relates to a pressure sensor module.

Conventionally, a pressure sensor module including a mounting substrate, a pressure sensor element and an integrated circuit element mounted on the mounting substrate, and a lid that covers the pressure sensor element and the integrated circuit element is known. Patent Document 1 (International Publication No. 2013/129444) discloses an example of a pressure sensor module (paragraphs [0021] to [0045], FIG. 1A, FIG. 4A, FIG. 7A, etc.).

The pressure sensor element has a diaphragm to which pressure such as atmospheric pressure is applied, detects the deformation amount of the diaphragm due to the pressure by the detection element, and outputs a detection signal. The integrated circuit element has a circuit that processes a detection signal of the pressure sensor element. The lid body is provided with a through hole (pressure introduction hole) for transmitting a change in external pressure to the inside of the lid body.

In the pressure sensor module, when light from the external space of the lid enters the internal space of the lid through the pressure introduction hole, the light is irradiated inside the integrated circuit when the integrated circuit element is irradiated with light. Electric power is generated, and the integrated circuit element may malfunction.

In order to solve such a problem, the pressure sensor module described in Patent Document 1 has a structure in which the pressure introduction hole has a light blocking portion. That is, since the pressure introducing hole is provided so that the hole axis is bent, there is no straight line that passes through only the inside of the through hole without passing through the lid and connects the external space and the internal space of the lid. With such a configuration, light from the external space of the lid cannot reach the internal space of the lid.

International Publication No. 2013/129444

In the pressure sensor module disclosed in Patent Document 1, the lid is manufactured by injection molding using a synthetic resin material. Here, if the lid has the pressure introducing hole having the light blocking portion as described above, it is difficult to remove the injection-molded lid from the mold. For this reason, there has been a problem that the manufacturing yield may be lowered, for example, the pressure introducing hole may be filled during the manufacture of the lid and the pressure introducing hole may not be formed. In order to improve the escape from the mold, it may be possible to enlarge the pressure introducing hole. However, if the pressure introducing hole is enlarged, the light shielding property by the light blocking portion may be lowered.

The present invention has been made in view of the above problems, and is a pressure sensor provided with a lid having a through-hole that can prevent the integrated circuit element from being irradiated with light and has a high manufacturing yield. The purpose is to provide modules.

The present invention provides a circuit board having a wiring conductor;
An integrated circuit element disposed on the first surface of the circuit board and electrically connected to the wiring conductor;
A pressure sensor element disposed on the first surface side of the circuit board and electrically connected to the integrated circuit element;
A lid that is disposed on the first surface side of the circuit board so as to cover the integrated circuit element and the pressure sensor element, and is fixed to the circuit board,
The lid has a through hole communicating with the external space and the internal space of the lid,
There is a straight line connecting the external space and the internal space through the inside of the through hole without passing through the lid, and the external space and the passage through the inside of the through hole without passing through the lid. The pressure sensor module is characterized in that the through hole is provided so that a straight line connecting the integrated circuit element does not exist.

The through hole is provided in a part of the lid body having a planar inner wall surface,
It is preferable that the angle formed by the opening surface of the through hole on the inner space side and the inner wall surface located on the inner space side from the opening surface is 90 ° or less. The angle is more preferably 70 ° to 90 °.

Moreover, it is preferable that there is no straight line that passes through the through hole without passing through the lid and connects the external space and the pressure sensor element.

Moreover, it is preferable that the said cover body is metal.
Moreover, it is preferable that the shape of the opening part by the side of the said internal space is a semicircle or a triangle.

The pressure sensor element may include a microphone.

According to the present invention, it is possible to provide a pressure sensor module provided with a lid having a through-hole, which can prevent the integrated circuit element from being irradiated with light and has a high manufacturing yield.

It is sectional drawing which shows schematically the structure of the pressure sensor module of this embodiment. It is the elements on larger scale of the pressure sensor module shown in FIG. It is a figure for demonstrating the shape of the through-hole of the cover body in the pressure sensor module of this embodiment. (A) is a figure similar to FIG. (B) shows an example of the shape of the opening part of the through-hole of a cover body. (C) shows another example of the shape of the opening part of the through-hole of a cover body. It is a schematic diagram which shows the state by which the through-hole is provided with respect to the base material of a cover body. It is a figure which shows schematically the structure of an example of a pressure sensor element. (A) is a top view, (b) is a longitudinal sectional view, and (c) is a transverse sectional view.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings of the present invention, the same reference numerals represent the same or corresponding parts. In addition, dimensional relationships such as length, width, thickness, and depth are changed as appropriate for clarity and simplification of the drawings, and do not represent actual dimensional relationships.

Referring to FIG. 1, the pressure sensor module of the present embodiment mainly includes a circuit board 1, an integrated circuit element 2, a pressure sensor element 3, and a lid 4.

The integrated circuit element 2 is mounted on a first surface of a circuit board (mounting board) 1 via a die bond agent 21. The pressure sensor element 3 is mounted on the integrated circuit element 2 via a die bond agent 31.

The circuit board 1 has a wiring conductor (not shown) and an external terminal 11 electrically connected to the wiring conductor. The integrated circuit element 2 is electrically connected to the wiring conductor of the circuit board 1 through the metal wire 22. The pressure sensor element 3 is electrically connected to the integrated circuit element 2 through a metal wire 32. For these electrical connections, bumps or the like may be used instead of metal wires.

The pressure sensor element 3 has a diaphragm (not shown) to which pressure such as atmospheric pressure is applied, detects the amount of deformation of the diaphragm due to the pressure, and outputs a detection signal. As the pressure sensor element (detection element) 3, for example, a capacitance element or a piezoresistive element can be suitably used. The pressure sensor element 3 may be a microphone that measures sound pressure. The integrated circuit element 2 has a circuit that processes the detection signal of the pressure sensor element 3.

In the present invention, it is not always necessary to mount the pressure sensor element 3 on the integrated circuit element 2, and the integrated circuit element 2 and the pressure sensor element 3 may be separately disposed on the circuit board 1. The integrated circuit element 2 may be mounted on the pressure sensor element 3. The relative position of the pressure sensor element 3 and the integrated circuit element 2 is not particularly limited.

The lid 4 is arranged so as to cover the pressure sensor element 3, the integrated circuit element 2, and the

metal wires

22 and 32. The lid 4 is bonded to the circuit board 1 with an adhesive, a conductive paste, solder, or the like.

In the present embodiment, the lid 4 is made of metal. When the lid 4 is made of metal, the through hole 41 can be easily formed by press working. In addition, since the metal has a higher rigidity than the resin, the thickness of the lid 4 can be reduced, and the pressure sensor module can be reduced in size and thickness.

The thickness of the lid 4 is not particularly limited, but it is preferable that the thickness is equal to or more than the minimum necessary considering the strength. On the other hand, if the lid 4 is too thick, it is difficult to process the through-hole 41, or the protruding portion into the lid 4 becomes large, and the protruding portion may contact the metal wire and short-circuit. There is sex. The thickness of the lid 4 is, for example, about 0.1 mm.

The lid 4 is provided with a through hole (pressure introduction hole) 41 for transmitting a change in pressure in the external space 43 to the internal space 42 of the lid 4.

Referring to FIG. 2, the shape condition of the through hole 41 and the positional relationship between the through hole 41 and the integrated circuit element 2 will be described. As shown in FIG. 2, the through hole 41 is provided in the ceiling wall of the lid body 4 (a part of the lid body 4 having a planar inner wall surface 41 c).

In the pressure sensor module of the present embodiment, the through hole 41 has a straight line X (see FIG. 2) that passes through the inside of the through hole 41 without passing through the lid 4 and connects the external space 43 and the internal space 42. Is provided. Thereby, even when producing the lid 4 by injection molding or the like, the molded lid can be easily removed from the mold.

The range of light entering the internal space 42 of the lid 4 is a range closer to the internal space 42 (on the right side of the open surface 41b in FIG. 2) than the opening surface 41b of the through hole 41 on the internal space 42 side. If the integrated circuit element 2 is arranged at a position other than the range where the light hits, the malfunction of the integrated circuit element 2 can be avoided. Further, if the pressure sensor element 3 is arranged at a position other than the range where the light hits, a change in output characteristics of the pressure sensor element can be avoided.

That is, in the pressure sensor module of the present embodiment, the through hole 41 is provided so that there is no straight line connecting the external space 43 and the integrated circuit element 2 through the inside of the through hole 41 without passing through the lid 4. ing. In other words, the shape of the through-hole 41 and the through-hole 41 so that the integrated circuit element 2 disposed in the internal space 42 of the lid 4 cannot be seen through the through-hole 41 from the external space 43 side of the lid 4. And the layout relationship between the integrated circuit element 2 are designed. Thereby, it is possible to prevent the integrated circuit element 2 from being irradiated with light, and it is possible to prevent malfunctions caused by the integrated circuit element 2 being irradiated with light.

Also, depending on the type of the pressure sensor element 3, the output characteristics of the pressure sensor element 3 may change when external light is irradiated. For this reason, in the pressure sensor of the present embodiment, the through hole 41 is provided so that there is no straight line that passes through the through hole 41 without passing through the lid body 4 and connects the external space 43 and the pressure sensor element 3. ing. With such a configuration, it is possible to prevent the pressure sensor element 3 from being irradiated with external light, and it is possible to prevent a change in output characteristics of the pressure sensor element 3.

It is preferable that the angle α formed between the opening surface 41b on the inner space 42 side of the through hole 41 and the inner wall surface 41c of the lid body 4 located on the inner space 42 side from the opening surface 41b is 90 ° or less. That is, it is preferable that the lid body 4 does not have an opening in a plan view as viewed from a direction perpendicular to the inner wall surface 41 c of the lid body 4. The smaller the angle α, the easier it is to design so that external light is not irradiated onto the integrated circuit element 2 and the pressure sensor element 3. Thereby, it can prevent more reliably that the integrated circuit element 2 is irradiated with light.

However, if the angle α is too small, it is difficult to remove the lid 4 from the mold when the lid body 4 is produced by injection molding. Therefore, the angle α is more preferably 70 ° to 90 °. Thereby, the cover body 4 can be easily produced by injection molding or the like.

The through-hole 41 is formed by pressing so that a part of the lid body 4 is recessed from the outside to the inside of the lid body 4. At this time, the shape of the through hole 41 is preferably a simple shape that can be easily processed, and is preferably a shape that allows the light incident on the inside of the lid 4 to have directivity.

The shape of the through hole 41 (the shape of the opening 41a on the inner space 42 side of the through hole 41) when the through hole 41 is viewed from the inner space 42 side of the lid 4 (the direction of the white arrow in the figure) is, for example, FIG. As shown in FIG. 3 (a) and FIG. 3 (b), it is a triangle or a semicircle. When the through-hole 41 is formed by pressing, the triangular through-hole 41 having a pointed tip is ideally easier to form, but in reality, there is a concern such as a scratch as a product. A through hole 41 having an intermediate shape between a triangle and a semicircle may be formed.

The size of the through-hole 41 needs to be large enough to take in the atmosphere or the like that is the subject of pressure measurement into the lid 4, but if it is too large, light from the outside easily enters and dust other than the atmosphere And the like easily enter the internal space 42 of the lid 4. For this reason, it is preferable to minimize the size of the through hole 41.

Specifically, for example, when the through-hole 41 having a shape as shown in FIGS. 3A and 3B is formed by press working, the through-hole shown in FIGS. 3A and 3B is used. The diameter of the circle C circumscribing the opening 41a on the inner space 42 side of 41 can be set to 10 to 30 μm. In addition, when forming the through-hole 41 by the process which extracts a simple round shape, it is difficult to manufacture the through-hole 41 of this size stably. Moreover, when the size of the through-hole 41 is set to this level, waterproofing at a living level is possible by the surface tension of the lid 4 made of metal. Usually, a porous waterproof sheet or the like is often used for waterproofing, but if the through hole 41 is of this size, a waterproof pressure sensor module can be provided without using an expensive waterproof sheet. I can do it.

Each of the through holes 41 may be drawn into the shape of the lid body 4 and pressed at the same time, but as shown in FIG. 4, the through holes 41 are first penetrated into the base material 40 of the lid body 4. After the hole 41 is pressed, the shape of the lid 4 may be drawn. In the latter case, the processing efficiency is good, and since the inspection of the size of the through hole 41 can be performed collectively in the state of the base material, the manufacturing efficiency is good.

Hereinafter, an example of a pressure sensor element when the pressure sensor element 3 is a capacitance element will be described with reference to FIG.

Referring to FIG. 5, pressure sensor element (capacitance element) 3 includes a wafer 301 containing Si, an insulating film 302 containing SiO ₂ , and membranes 303 (303a, 303b, 303c) containing Si single crystals. It has a configured SOI (Silicon on Insulator) structure.

Based on the change in capacitance (detection capacitance) between the central membrane 303a and the wafer 301, the amount of deformation of the membrane (diamond) 302 is detected. That is, the membrane 303a corresponds to a diaphragm.

Using the electrostatic capacitance (reference capacitance) between the membrane 303b provided around the membrane 303a and the wafer 301, the integrated circuit element 2 is affected by the force applied to the pressure sensor element 3 from the outside (pressure sensor element). 3) and temperature characteristics are corrected.

The membrane 303c (guard electrode) provided around the membrane 303b functions as a shield.

The four pads 304 provided on the surface of the pressure sensor element 3 are connected to the membrane 303a, the membrane 303b, the membrane 303c (guard electrode), and the wafer 301, respectively.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 circuit board, 11 external terminal, 2 integrated circuit element, 21, 31 die bond agent, 22, 32 metal wire, 3 pressure sensor element, 4 lid, 40 base material, 41 through hole, 41a opening, 41b opening surface, 41c inner wall surface, 42 inner space, 43 outer space, 301 wafer, 302 insulating film, 303, 303a, 303b, 303c membrane, 304 pad.

Claims

A circuit board having a wiring conductor;
An integrated circuit element disposed on the first surface of the circuit board and electrically connected to the wiring conductor;
A pressure sensor element disposed on the first surface side of the circuit board and electrically connected to the integrated circuit element;
A lid that is disposed on the first surface side of the circuit board so as to cover the integrated circuit element and the pressure sensor element, and is fixed to the circuit board,
The lid has a through hole communicating with the external space and the internal space of the lid,
There is a straight line connecting the external space and the internal space through the inside of the through hole without passing through the lid, and the external space and the passage through the inside of the through hole without passing through the lid. The pressure sensor module, wherein the through hole is provided so that a straight line connecting the integrated circuit element does not exist.
The through hole is provided in a part of the lid body having a planar inner wall surface,
2. The pressure sensor module according to claim 1, wherein an angle formed between an opening surface of the through hole on the inner space side and the inner wall surface located on the inner space side with respect to the opening surface is 90 ° or less.
The pressure sensor module according to claim 2, wherein the angle is 70 ° to 90 °.
The pressure sensor module according to any one of claims 1 to 3, wherein there is no straight line that passes through the through hole without passing through the lid and connects the external space and the pressure sensor element.
The pressure sensor module according to any one of claims 1 to 4, wherein the lid is made of metal.
The pressure sensor module according to any one of claims 1 to 5, wherein a shape of the opening on the inner space side of the through hole is a semicircle or a triangle.
The pressure sensor module according to any one of claims 1 to 6, wherein the pressure sensor element includes a microphone.