JP2007178221A - Semiconductor device, its manufacturing method, and spacer manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce changes in the vibration characteristics of a diaphragm provided in a semiconductor chip in a semiconductor device provided with the semiconductor chip such as a sound pressure sensor chip, while improving manufacturing efficiency and reducing manufacturing costs. <P>SOLUTION: The semiconductor device 1 comprises a circuit board 3, the semiconductor chip 9 which is arranged on a surface 3a of the circuit board 3 and is provided with a thin-film diaphragm 9a which vibrates in accordance with a fluctuation in pressure, and a nearly plate-shaped spacer 5 which is fixed between the circuit board 3 and the semiconductor chip 9. The spacer 5 is formed with a through hole 17 for allowing the surface 3a of the circuit board 3 and the diaphragm 9a to face each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor device including a semiconductor chip such as a sound pressure sensor chip and a pressure sensor chip, a manufacturing method thereof, and a manufacturing method of a spacer used in the semiconductor device.

  Conventionally, in a semiconductor device such as a silicon microphone or a pressure sensor, a semiconductor chip having a diaphragm for detecting pressure fluctuations such as sound by vibration is mounted on the surface of a circuit board, such as a sound pressure sensor chip or a pressure sensor chip. (For example, refer to Patent Document 1). In a state where this kind of semiconductor chip is arranged on the surface of the circuit board, a cavity is formed between the diaphragm and the surface of the circuit board.

Here, when the volume of the hollow portion is small, the air spring constant of the hollow portion is increased and the diaphragm is less likely to vibrate. Therefore, the amount of displacement of the diaphragm is reduced and pressure fluctuations cannot be detected accurately. . That is, it is necessary to vibrate the diaphragm to ensure a sufficient size as the cavity. Further, the volume of the cavity needs to be changed as appropriate according to the characteristics of the semiconductor chip.
In the conventional semiconductor device, the volume of the cavity is increased by forming a recess recessed from the surface of the circuit board.
Special Table 2004-537182

However, in the above-described conventional semiconductor device, since the concave portion for securing the volume of the cavity is formed in the circuit board, the manufacturing of the circuit board becomes troublesome, the manufacturing efficiency of the semiconductor device is reduced, and the semiconductor device There is a risk that the manufacturing cost of the product increases.
The present invention has been made in view of the above-described circumstances, and is capable of suppressing a change in vibration characteristics of a diaphragm while improving manufacturing efficiency and reducing manufacturing cost, a manufacturing method thereof, and a semiconductor device. It aims at providing the manufacturing method of the spacer used for.

In order to solve the above problems, the present invention proposes the following means.
The invention according to claim 1 is a circuit board or a package in which a circuit is incorporated, and a semiconductor chip provided on the surface of the circuit board or the package and provided with a thin film diaphragm that vibrates in response to pressure fluctuations; A substantially plate-like spacer fixed between the circuit board or the package and the semiconductor chip, and a through hole is formed in the spacer so that the surface of the circuit board or the package and the diaphragm face each other. A semiconductor device characterized by the above is proposed.

  According to the semiconductor device of the present invention, the cavity is formed by the surface of the circuit board, the diaphragm of the semiconductor chip, and the through hole of the spacer in a state where the semiconductor chip is provided on the surface of the circuit board via the spacer. become. The volume of the cavity can be easily changed simply by changing the thickness dimension of the spacer and the size of the through hole. As a result, the volume of the cavity can be made larger. In other words, in this semiconductor device, it is not necessary to separately process the circuit board to form the recess as in the conventional case.

  According to a second aspect of the present invention, in the semiconductor device according to the first aspect, the spacer includes a cavity defined by the surface of the circuit board or the package, the diaphragm, and the through hole, and an outside of the cavity. Proposed is a semiconductor device characterized by allowing a gas flow based on a static pressure difference with an outer space located on the outer side and preventing a gas from passing based on a pressure fluctuation acting on the diaphragm. .

The invention according to claim 3 proposes a semiconductor device according to claim 1 or 2, wherein the spacer is made of a porous body.
The invention according to claim 4 proposes the semiconductor device according to claim 1 or 2, wherein a communication hole is formed in the spacer.

Here, the package in which the circuit is incorporated refers to an assembly in which a microphone chip and an LSI for microphone output signal processing already assembled in the same package are included, and wiring is included. For example, a lead frame molded like a pre-molded package or an LSI having functions such as an impedance converter, a charge pump, and an amplifier in a pre-molded package can be mentioned.
The static pressure indicates the pressure in the cavity or the outer space when the gas is stationary without flowing. The change in static pressure is a relatively small change in pressure per unit time, such as heating / cooling of a cavity, generation of outgas during reflow for bonding a spacer to a semiconductor chip or circuit board, etc. The static pressure change in the outer space based on the static pressure change in the cavity due to the height difference or the altitude difference is included in the static pressure change.
The pressure fluctuation indicates a dynamic pressure change due to sound or the like, and includes a pressure change per unit time larger than the static pressure change described above. That is, the aforementioned static pressure change in the cavity and static pressure change in the outer space are not included in this pressure fluctuation.

By the way, there was a difference in static pressure between the cavity and the outer space generated by pressure changes caused by heating / cooling of the semiconductor device and static pressure changes in the outer space due to altitude differences, etc. In some cases, even when the spacer is formed by the invention according to claim 1 to increase the volume of the cavity, it may not be sufficient to alleviate the difference in static pressure.
Therefore, according to the second aspect of the present invention, there is provided between the cavity defined by the surface of the circuit board or the package, the diaphragm and the through hole, and the outer space located on the outer side of the cavity. Even if such a difference occurs, by providing a spacer characterized by allowing the flow of gas based on a static pressure difference and preventing the passage of gas based on pressure fluctuation acting on the diaphragm, Since the diaphragm can be prevented from being deformed due to the difference in static pressure with the outer space, it is possible to reliably prevent the vibration characteristics of the diaphragm from changing.

  According to a third aspect of the present invention, in the semiconductor device according to the first or second aspect, the gas flow based on the static pressure difference is allowed and the passage of the gas based on the pressure fluctuation acting on the diaphragm is prevented. Therefore, in addition to adjusting the pressure difference, pressure fluctuations such as sound reach the diaphragm, and based on this, when a dynamic pressure difference occurs between the outer space and the cavity In addition, since the entry and exit of the gas through the gaps in the porous body is appropriately prevented, the diaphragm can be vibrated with high accuracy even with respect to the pressure fluctuation. Here, “appropriately prevent” means to prevent a value equal to or higher than the frequency of a sound that begins to be heard by a human when there is a temporal variation in pressure.

  Further, according to a fourth aspect of the present invention, in the semiconductor device according to the first or second aspect, the gas flow based on the static pressure difference is allowed and the passage of the gas based on the pressure fluctuation acting on the diaphragm is prevented. Adjust the pressure difference. For example, when pressure fluctuations such as sound reach the diaphragm, and a dynamic pressure difference is generated between the outer space and the cavity based on this, the gas enters and exits through the communication hole appropriately. Therefore, the diaphragm can be vibrated with high accuracy even with respect to the pressure fluctuation.

  Further, the spacer does not need to be formed in a thin film shape like a diaphragm, or include an electrical wiring portion like a circuit board inside. For this reason, compared with the case where the same communication hole is formed in the circuit board, a fine communication hole that restricts the gas flow between the cavity and the outer space can be easily formed in the spacer. In addition, the spacer itself can be formed from a porous body. Therefore, it is possible to improve the manufacturing efficiency of the semiconductor device and reduce the manufacturing cost of the semiconductor device.

According to a fifth aspect of the present invention, in the semiconductor device according to the fourth aspect, the spacer includes a substantially plate-like base substrate, a thin film-like first film layer formed on the surface of the base substrate, A thin film-like second film layer formed on the surface of the first film layer, and the communication hole is formed through a slit-like notch formed in the first film layer, and the notch The semiconductor device is characterized by being defined by the surface of the base substrate and the back surface of the second film layer facing each other.
According to the semiconductor device of the present invention, the communication hole can be easily formed simply by forming a slit-shaped notch in the first film layer and sandwiching the first film layer between the base substrate and the second film layer. Can be formed.

According to a sixth aspect of the present invention, there is provided a semiconductor device according to any one of the first to fifth aspects, wherein the spacer is formed to be elastically deformable. Yes.
According to the semiconductor device of the present invention, even if the circuit board vibrates, the vibration can be absorbed by the elastic force of the spacer, and therefore the diaphragm can be prevented from vibrating based on the vibration of the circuit board. That is, the vibration of the circuit board can be prevented from being detected as noise in the diaphragm. Moreover, the stress accompanying the hardening of the adhesive during die bonding can be relaxed.

The invention according to claim 7 proposes the semiconductor device according to any one of claims 1 to 6, wherein the spacer has a thermal expansion coefficient close to that of the semiconductor chip. is doing.
According to the semiconductor device of the present invention, even when the spacer and the semiconductor chip are heated or cooled, the spacer and the semiconductor chip have similar thermal expansion coefficients, and therefore no stress is generated in the diaphragm. In addition, when the circuit board and the spacer have mutually different thermal expansion coefficients, the semiconductor device is heated or cooled, and the circuit board and the spacer are separated from each other based on the difference in the thermal expansion coefficient described above. However, this stress can be relaxed in the spacer. Therefore, it is possible to suppress the occurrence of stress in the diaphragm and the change of its vibration characteristics.

According to an eighth aspect of the present invention, in the semiconductor device according to any one of the first to seventh aspects, the spacer is formed with an engagement recess recessed from a surface facing the semiconductor chip, and the semiconductor A semiconductor device is proposed in which a chip is engaged with the engaging recess and attached to the spacer.
According to the semiconductor device of the present invention, when the semiconductor chip is engaged with the engaging recess, the semiconductor chip can be easily positioned with respect to the spacer when the semiconductor device is manufactured.

  The invention according to claim 9 is fixed between a circuit board or a package in which a circuit is incorporated and a semiconductor chip having a thin film diaphragm that vibrates in response to pressure fluctuations. A method of manufacturing a spacer having a through-hole that allows a surface and the diaphragm to face each other, wherein the first thin film forms a thin film-like first film layer on the surface of a substantially plate-like base substrate Forming the first film layer from the surface thereof by etching the first film layer so as to reach the end of the surface along the surface of the base substrate from the through hole. An etching step for forming a recessed slit-shaped cutout, and a communication hole that covers the cutout and communicates from the through hole to the end, Proposes a manufacturing method of the spacer, characterized in that the surface of serial first film layer and a second thin film forming step of forming a thin film second film layer.

According to a tenth aspect of the present invention, there is provided a semiconductor chip comprising a circuit board or a package in which a circuit is incorporated, and a thin film diaphragm which is arranged on the surface of the circuit board or the package and vibrates in response to pressure fluctuations. And a substantially plate-like spacer fixed between the circuit board or the package and the semiconductor chip, and a through hole for allowing the surface of the circuit board or the package and the diaphragm to face each other is provided in the spacer. A method of manufacturing a formed semiconductor device, wherein the spacer forms a first thin film layer that can be etched on the surface of a substantially plate-like base substrate, and the first thin film forming step, Etching is performed on the film layer to reach the end of the surface along the surface of the base substrate from the through hole. An etching step for forming a slit-like cutout recessed from the surface of the first film layer, and a communication hole that covers the cutout and communicates from the through hole to the end, A method of manufacturing a semiconductor device is proposed, which is manufactured by a second thin film forming step of forming a thin film-like second film layer on the surface of the first film layer.
According to the manufacturing method of the spacer and the semiconductor device according to the present invention, the notch portion that forms the communication hole is formed by etching, so that the width dimension of the notch portion can be adjusted with high accuracy. That is, a notch with a small width can be easily formed.

  According to the first aspect of the present invention, since the volume of the cavity can be simply changed by appropriately changing the thickness dimension of the spacer and the size of the through hole, the strength of the air spring in the cavity can be increased. It can be adjusted so that the vibration of the diaphragm is not suppressed. Therefore, a product including a high-quality semiconductor device can be manufactured.

In addition, according to the invention according to any one of claims 2 to 4, the static pressure in the cavity and the outer space is substantially reduced by allowing the gas to enter and exit through the communication hole and the gap between the porous bodies. Since it can be made equivalent, it can prevent reliably that the vibration characteristic of a diaphragm changes.
In addition, even if a dynamic pressure difference occurs between the outer space and the cavity based on pressure fluctuations such as acoustics, gas entry and exit through the communication hole and the gap between the porous bodies is limited. The diaphragm can be vibrated accurately with respect to the pressure fluctuation.
Furthermore, it is easier to form a communication hole in the spacer or to form the spacer itself from a porous body than to form a similar communication hole in the circuit board, so that the manufacturing efficiency of the semiconductor device is improved. The manufacturing cost of the semiconductor device can be reduced.

According to the fifth aspect of the present invention, the communication hole can be easily formed simply by sandwiching the first film layer having the slit-shaped cutout portion between the base substrate and the second film layer to form a spacer. Can be formed.
According to the sixth aspect of the present invention, it is possible to prevent the vibration of the circuit board from being detected as noise, and therefore it is possible to detect only pressure fluctuations such as sound with higher accuracy.

According to the invention of claim 7, since the spacer and the semiconductor chip have a thermal expansion coefficient close to each other, stress is generated in the diaphragm of the semiconductor chip based on the difference in the thermal expansion coefficient from the circuit board. It can suppress that it changes and the vibration characteristic of a diaphragm changes.
According to the eighth aspect of the invention, since the semiconductor chip can be easily positioned with respect to the spacer, the manufacturing efficiency of the semiconductor device can be improved.

  Moreover, according to the invention which concerns on Claim 9 and Claim 10, since the notch which comprises a communicating hole can be formed by an etching process, a minute communicating hole can be formed easily.

1 to 11 show an embodiment of the present invention. As shown in FIG. 1, the semiconductor device 1 according to this embodiment is fixed to a circuit board 3, a substantially plate-like spacer 5 and IC 7 fixed to the surface 3 a of the circuit board 3, and the surface 5 a of the spacer 5. The semiconductor chip 9 is provided. Further, the semiconductor device 1 is provided with a lid portion 11 that is disposed on the surface 3 a of the circuit board 3 and covers the spacer 5, the IC 7, and the semiconductor chip 9.
The circuit board 3 is a so-called multilayer wiring board in which an electrical wiring portion (not shown) is provided, and is electrically connected to the IC 7 and the semiconductor chip 9.

The lid portion 11 includes a substantially plate-like upper end wall portion 13 disposed at a position spaced from the surface 3 a of the circuit board 3 in the thickness direction, and a substantially annular side wall fixed to the periphery of the surface 3 a of the circuit board 3. Part 15. That is, the lid portion 11 is formed in a substantially concave shape that opens to the tip end side of the side wall portion 15 by the upper end wall portion 13 and the side wall portion 15. Therefore, in a state where the front end portion of the side wall portion 15 is disposed on the surface 3 a of the circuit board 3, a hollow space (outer space) S <b> 1 is defined by the circuit board 3 and the lid body portion 11.
The hollow space S1 communicates with an outer space located outside the semiconductor device 1 through an opening 14 formed in the upper end wall portion 13.

The semiconductor chip 9 is a so-called sound pressure sensor chip that converts sound into an electrical signal. That is, the semiconductor chip 9 includes a diaphragm 9 a that vibrates in response to pressure fluctuations such as sound from an outer space located outside the semiconductor device 1. The diaphragm 9 a is configured to vibrate in the thickness direction of the semiconductor chip 9.
The IC 7 is for operating the semiconductor chip 9. For example, an amplifier circuit for amplifying an electric signal from the semiconductor chip 9, a DSP (digital signal processor) for processing the electric signal as a digital signal, An A / D converter and the like are included. The IC 7 is fixed to the surface 3a of the circuit board 3 through an adhesive 12 such as a silver paste.

The spacer 5 is fixed to the circuit board 3 via an adhesive 16 such as a silver paste between the back surface 5 b and the front surface 3 a of the circuit board 3. The spacer 5 is formed with a through hole 17 penetrating in the thickness direction.
In the semiconductor chip 9 described above, an adhesive 18 such as silver paste is used so that the through hole 17 is covered with the diaphragm 9a and the diaphragm 9a is opposed to the surface 3a of the circuit board 3 through the through hole 17. Are fixed to the surface 5 a of the spacer 5. That is, the through hole 17 forms a cavity S2 between the diaphragm 9a and the circuit board 7. This hollow portion S2 communicates with the hollow space S1 through a fine communication hole 19 formed in the spacer 5.
In the state where the circuit board 3, the spacer 5, and the semiconductor chip 9 are fixed to each other, no gap is generated between the circuit board 3 and the spacer 5 and between the spacer 5 and the semiconductor chip 9. That is, the hollow space S1 and the cavity S2 are communicated with each other only by the communication hole 19 described above.

  The communication hole 19 is large enough to allow a gas flow between the hollow space S1 and the cavity S2 based on the static pressure difference when a static pressure difference occurs between the hollow space S1 and the cavity S2. Is formed. Here, the static pressure in this embodiment indicates the pressure in the hollow space S1 and the cavity S2 in a state where the gas is stationary without flowing. The change in the static pressure is based on, for example, static pressure change in the cavity S2 due to heating / cooling of the semiconductor device 1 or generation of outgas during reflow of the adhesives 16 and 18, an altitude difference, or the like. The static pressure change in the outer space or the hollow space S1 is included in the static pressure change.

Further, the communication hole 19 is provided between the hollow space S1 and the cavity S2 even if a pressure difference occurs between the pressure of the hollow space S1 and the pressure of the cavity S2 due to pressure fluctuations such as sound acting on the diaphragm 9a. It is formed in a size that prevents the passage of gas.
Here, the pressure fluctuation indicates a dynamic pressure change due to sound or the like, and includes a pressure change per unit time larger than the static pressure change described above. That is, the static pressure change in the cavity S2 and the static pressure change in the outer space or the hollow space S1 described above are not included in the pressure fluctuation.

As shown in FIGS. 2 and 3, the spacer 5 is configured by sequentially laminating a thin film-like first film layer 23 and a second film layer 25 on a surface 21 a of a substantially plate-like base substrate 21. .
The base substrate 21, the first film layer 23, and the second film layer 25 are formed with substantially circular holes 27, 29, and 31, respectively, in plan view. The spacers are formed by these three holes 27, 29, and 31. Five through holes 17 are formed. The first film layer 23 has two slit-shaped notches 33 formed along the surface 21a of the base substrate 21, and the two notches 33 and the base substrate facing each other through the two notches 33 are formed. Two communication holes 19 of the spacer 5 are constituted by the front surface 21 a of 21 and the back surface 25 b of the second film layer 25.

Next, a method for manufacturing the semiconductor device 1 configured as described above will be described. When the semiconductor device 1 is manufactured, the spacer 5 having the above-described configuration is manufactured in advance.
That is, when manufacturing the spacer 5, first, as shown in FIGS. 5 and 6, a substantially plate-like base substrate 21 having a substantially circular hole 27 in plan view is prepared. Next, as shown in FIGS. 7 to 9, a thin film-like first film layer 23 is formed on the surface 21 a of the base substrate 21 so as to cover the holes 27 of the base substrate 21 (first thin film forming step). The first film layer 23 is made of a material that can be etched.
Thereafter, a resist layer (not shown) is formed on the surface 23a of the first film layer 23 excluding the portions where the notches 33 and the holes 29 are formed, and the notches 33 and the holes 29 are formed by etching (etching process). ). The notch 33 is formed to be recessed from the surface 23 a of the first film layer 23 so as to reach the end of the surface 21 a along the surface 21 a of the base substrate 21. After the etching process is completed, the resist layer is removed. Further, when the first film layer 23 is formed from a material that can be etched such as a dry film, at least the dry film itself becomes a resist material, so that a thin film forming step (laminating step), exposure Through the process and the development process, the notch 33 and the hole 29 can be formed.

2-4, the second film layer 25 is formed on the surface 23a of the first film layer 23 so as to cover the notch 33 and the holes 27, 29 (second thin film forming step). ). Similarly to the first film layer 23, the second film layer 25 is also formed of a material that can be etched.
After completion of the second thin film forming step, a resist layer (not shown) is formed on the surface 5a of the second film layer 25 excluding the portion where the holes 31 are formed, and holes are formed by etching. Finally, the resist layer described above is removed, and the manufacture of the spacer 5 is completed.
Here, the manufacturing method in the case where one spacer is formed has been described. However, the present invention is not limited to this. For example, the base substrate 21 is formed from one large plate-like member, and the first member is formed on the plate-like member. The film layer 23 and the second film layer 25 may be laminated, or a large number of holes 27, 29, and 31 may be formed, and then the individual spacers 5 may be cut by dicing. In this case, since a large number of notches 33 and holes 27, 29, and 31 can be formed at a time by a single etching process, the manufacturing efficiency of the spacer 5 can be improved.

Then, the semiconductor device 1 shown in FIG. 1 is assembled using the spacer 5 manufactured as described above.
That is, first, as shown in FIG. 10, a substantially annular side wall 15 is fixed to the periphery of the surface 3a of the circuit board 3, and the IC 7 and the spacer are attached to the surface 3a of the circuit board 3 via adhesives 12 and 16. 5 is fixed. In this case, the spacers 5 and the IC 7 may be disposed after the adhesives 12 and 16 are previously attached to the surface 3 a of the circuit board 3. The gap between the front surface 3 a of the circuit board 3 and the back surface 5 b of the spacer 5 can be filled with the adhesive 16. Next, the IC 7 is electrically connected to the circuit board 3.
Thereafter, as shown in FIG. 11, the semiconductor chip 9 is fixed to the surface 5 a of the spacer 5 through the adhesive 18. In this case, the semiconductor chip 9 may be disposed after the adhesive 18 is previously attached to the surface 5 a of the spacer 5. Finally, as shown in FIG. 1, the upper end wall portion 13 is fixed to the side wall portion 15 to form the lid portion 11, thereby completing the manufacture of the semiconductor device. This manufacturing process is merely an example. For example, after the semiconductor chip 9 is bonded to the spacer 5, the spacer 5 may be fixed to the surface 3 a of the circuit board 3.

  According to the semiconductor device 1 described above, the volume of the cavity S2 defined by the surface 3a of the circuit board 3, the diaphragm 9a of the semiconductor chip 9 and the through hole 17 of the spacer 5 is the thickness dimension of the spacer 5 and the through hole 17. It can be easily changed simply by changing the size of. For this reason, it can suppress that the air spring constant of cavity part S2 becomes large, and can suppress that the vibration characteristic of the diaphragm 9a changes. In addition, since the cavity S2 can be formed without forming the recess by separately processing the circuit board 3 as in the prior art, the manufacturing cost of the semiconductor device 1 can be kept low.

Further, the cavity S2 and the hollow space S1 and the outer side are changed by the pressure change of the cavity S2 based on heating and cooling of the semiconductor device 1 and the static pressure change of the hollow space S1 and the outer space based on the altitude difference. When there is a difference in static pressure between the spaces, gas enters and exits between the hollow portion S2 and the hollow space S1 or the outer space through the communication hole 19, so that the static pressure in the hollow portion S2 is hollow. This is substantially the same as the static pressure in the space S1 and the outer space. Therefore, the diaphragm 9a can be prevented from being deformed due to the difference in static pressure between the hollow portion S2 and the hollow space S1 or the outer space, so that the vibration characteristics of the diaphragm 9a can be reliably prevented from changing. be able to.
Furthermore, even when a pressure fluctuation such as sound reaches the diaphragm 9a and a dynamic pressure difference is generated between the hollow space S1 or the outer space and the cavity S2 based on this, the communication hole 19 is interposed. Since the entry and exit of the gas is prevented, the diaphragm 9a can be vibrated with high accuracy against the pressure fluctuation.

Further, the communication hole 19 can be easily formed in the spacer 51 simply by sandwiching the first film layer 23 in which the slit-shaped notch 33 is formed between the base substrate 21 and the second film layer 25. In particular, since the width dimension of the notch 33 can be adjusted with high accuracy by forming the notch 33 by etching when the spacer 5 is manufactured, the minute communication hole 19 having a small width dimension can be easily formed. Can do. In addition to this, by selecting the first film layer 23 having a small thickness, the fine communication hole 19 having a small cross-sectional area can be formed.
That is, compared with the case where the same communication hole 19 is formed in the circuit board 3, the minute communication hole 19 that restricts the flow of gas between the cavity S <b> 2 and the hollow space S <b> 1 or the outer space is provided in the spacer 5. It can be formed easily.

In the above-described embodiment, the hole 27 of the base substrate 21 constituting the through hole 17 of the spacer 5 is formed in advance before the first thin film forming step. However, the present invention is not limited to this. Alternatively, it may be formed simultaneously with the holes 29 of the first film layer 23 by etching. In this case, however, the base substrate 21 is also preferably formed from a material that can be etched.
Moreover, although the upper end wall part 13 and the side wall part 15 which comprise the cover body part 11 were formed with a separate member, it does not restrict to this, For example, you may form integrally. In the case of this configuration, the lid 11 may be fixed to the circuit board 3 after the spacer 5, the IC 7 and the semiconductor chip 9 are arranged on the surface 3 a of the circuit board 3.

  Further, the adhesion between the spacer 5 and the semiconductor chip 9 or the adhesion between the circuit board 3 and the spacer 5 is performed after the adhesives 16 and 18 are attached to the surface 5 a of the spacer 5 or the surface 3 a of the circuit board 3. However, it is not limited to this. That is, for example, as shown in FIG. 12, adhesive sheets 41 and 43 are previously attached to the front surface 5a and the back surface 5b of the spacer 5, respectively, and the spacer 5 and the semiconductor chip 9 or the circuit board 3 are bonded by the adhesive sheets 41 and 43. It does not matter if bonding is performed. Alternatively, an adhesive sheet may be attached to the circuit board 3 side first.

In addition, although the two communication holes 19 are formed in the spacer 5, the present invention is not limited to this, and for example, only one may be formed as shown in FIG. Two or more may be formed.
Furthermore, the spacer 5 may be formed to be elastically deformable by rubber or the like. Furthermore, for example, at least one of the base substrate 21, the first film layer 23, and the second film layer 25 constituting the spacer 5 may be formed of an elastically deformable material.
In the case of this configuration, even if the circuit board 3 vibrates, the vibration can be absorbed by the elastic force of the spacer 5, so that the diaphragm 9 a can be prevented from vibrating due to the vibration of the circuit board 3. That is, it is possible to prevent the vibration of the circuit board 3 from being detected as noise in the diaphragm 9a, and it is possible to detect only pressure fluctuations such as sound more accurately.

  Further, in this configuration, when the spacer 5 and the circuit board 3 are fixed by the adhesives 16 and 18 and the adhesive sheets 41 and 43, the adhesives 16 and 18 and the adhesive sheets 41 and 43 are cured. The shrinkage of the adhesives 16 and 18 and the adhesive sheets 41 and 43 is alleviated by the elastic force of the spacer 5. Therefore, it is possible to prevent stress from being generated in the diaphragm 9a of the semiconductor chip 9 based on this contraction, and to prevent the vibration characteristics of the diaphragm 9a from changing.

  The spacer 5 may have the same or close thermal expansion coefficient as that of the semiconductor chip 9. In this configuration, even if the spacer 5 and the semiconductor chip 9 are heated or cooled, no stress is generated in the diaphragm 9a. Further, when the circuit board 3 and the spacer 5 have mutually different thermal expansion coefficients, the semiconductor device 1 is heated or cooled, and the circuit board 3 and the spacer 5 are separated from the circuit board 3 based on the above-described difference in thermal expansion coefficient. Although stress is generated between the spacer 5 and the spacer 5, this stress can be relaxed. Therefore, it is possible to suppress the occurrence of stress in the diaphragm 9a and the change in the vibration characteristics thereof.

In addition, as a material of the spacer 5 mentioned above, for example, copper tungsten (80W-20Cu, 70W-30Cu), copper molybdenum (85Mo-15Cu), tungsten, molybdenum, alumina ceramics (Al2O3), silica ceramics (SiO2), silicon Carbide ceramics (SiC), tantalum, graphite and the like are used.
Further, a silicon substrate can be used as the substrate constituting the semiconductor chip 9. For example, the thermal expansion coefficients of copper tungsten (70W-30Cu) and silicon substrate are 10.2 ppm / ° C. and 3.0 ppm / ° C., respectively, and the difference between the thermal expansion coefficients is 7.2 ppm / ° C. That is, it is desirable to select a material such that the difference between the thermal expansion coefficients of the spacer 5 and the semiconductor chip 9 is 7.2 ppm / ° C. or less.

Furthermore, the spacer 5 is configured by sequentially laminating the base substrate 21, the first film layer 23, and the second film layer 25, but is not limited to this, and at least the through hole 17 and the communication hole 19. May be formed, that is, it may be formed of one member.
In addition, the spacer 5 is provided with the communication hole 19, but the present invention is not limited to this, and at least allows the gas to flow based on the static pressure difference between the hollow space S <b> 1 and the hollow portion S <b> 2 and acts on the diaphragm. What is necessary is just to be formed so that the passage of the gas based on a pressure fluctuation may be prevented.

That is, the spacer 5 may be formed of, for example, a porous body. In the case of this configuration, the porous body may be formed so as to encourage the gas to enter and exit between the hollow space S1 and the cavity S2 under the above-described conditions through the gap between the porous bodies. Even in this configuration, the same effect as when the communication hole 19 is formed in the spacer 5 can be obtained.
Even if the spacer is made of a porous material as described above, it may be made of an elastically deformable material such as a sponge, or made of a material having a thermal expansion coefficient that is the same as or close to that of a semiconductor chip. It may be done.

(Example 2)
The spacer 5 is not limited to the structure described above. For example, as shown in FIG. 14, in addition to the base substrate 21, the first film layer 23, and the second film layer 25 similar to the above embodiment, the third film layer 51 is formed on the entire back surface 21 b of the base substrate 21. The spacer 52 may be provided and the third film layer 51 may close the opening of the through hole 17. Here, the third film layer 51 is formed of the same dry film as the first film layer 23 and the second film layer 25.
The dry film constituting the third film layer 51 enters the hole 27 or the recess that opens in the back surface 21b of the base substrate 21, and is bonded to the base substrate 21 by adhesion. In the spacer 52 having this configuration, the adhesive 16 does not need to be fixed to the surface 3a of the circuit board 3 via the adhesive 16 such as silver paste unlike the spacer 5 of the above embodiment. It is possible to prevent a change in the volume of the cavity S2 generated by entering.

(Example 3)
Further, the notch 33 constituting the communication hole 19 is formed in the first film layer 23 sandwiched between the base substrate 21 and the second film layer 25, but is not limited thereto. For example, as shown in FIG. 15, it may be formed on the third film layer 51. That is, a slit-like cutout 53 is formed in the third film layer 51 along the back surface 21 b of the base substrate 21. Then, by fixing the spacer 54 to the surface 3 a of the circuit board 3 so that the back surface 51 b of the third film layer 51 faces the surface 3 a of the circuit board 3, the notches 53 and the surface 3 a of the circuit board 3 are used. A communication hole 55 similar to that in the above embodiment can be configured.
However, in the case of this configuration, it is preferable to fix the spacer 54 to the surface 3 a of the circuit board 3 by the sheet-like adhesive 56 instead of the paste-like adhesive 16 such as silver paste as in the above embodiment. That is, when the fixing is performed with the paste adhesive 16, the notch 53 may be filled with the adhesive 16, but when the fixing is performed with the sheet adhesive 56, the notch 53 is as described above. This is because it becomes difficult to be buried.
In the case of this configuration, only one film layer that does not have the above-described notch, for example, only the second film layer 25 similar to the above embodiment, may be formed on the surface 21a of the base substrate 21. That's fine.

Example 4
Further, the base member 21 is configured by forming the hole 27 having a substantially circular shape in plan view. However, the present invention is not limited to this. For example, as shown in FIG. By forming the inside of the substantially circular large-diameter hole 57 in a mesh shape, a large number of minute holes 58 penetrating in the thickness direction of the base substrate 21 may be formed.
In the case of this configuration, since tenting reinforcement of the base substrate 21 is performed by forming a part of the base substrate 21 in a mesh shape, compared to the case of forming the hole 27 as in the above embodiment, The rigidity of the base substrate 21 can be improved, and the structure of the entire spacer 59 can be strengthened.

(Example 5)
Further, although the hole 27 and the minute hole 58 are formed in the base substrate 21, the present invention is not limited to this. For example, the hole 27 and the minute hole 58 are formed in the base substrate 61 as shown in FIG. In other words, the base substrate 61 may be formed so as to close the opening of the hole 29 of the first film layer 23. However, in the case of this configuration, the thickness dimensions of the two film layers 23 and 25 and the holes 29 and 31 formed in the film layers 23 and 25 so that a sufficiently large cavity S2 can be secured. It is preferable to increase the diameter.
In this configuration, unlike the above-described embodiment, it is not necessary to form the hole 27 and the minute hole 58 described in the above-described embodiment in the base substrate 61. Therefore, the spacer 63 can be easily manufactured and the spacer 63 can be manufactured. The overall structure can be strengthened. In addition, since the surface does not have irregularities after the film layers 23 and 25 are laminated on the base substrate 61, the photolithography and the etching process are facilitated.

(Example 6)
In the above embodiment, the semiconductor chip 9 is arranged on the surface 5a of the spacer 5. However, the present invention is not limited to this. For example, as shown in FIG. 18, the spacer 5 is recessed from the surface 5a. A mating recess 45 may be formed, and the semiconductor chip 9 may be engaged and attached to the engagement recess 45. The engaging recess 45 is not limited to being formed integrally with the second film layer 25. For example, as shown in FIG. 19, a positioning layer 71 is formed on the surface 25a of the second film layer 25, and positioning holes 73 larger than the second film layer 25 are formed in the positioning layer 71, so that the second The engaging recess 75 may be constituted by the surface 25 a of the film layer 25 and the positioning hole 73.

In the case of these configurations, since the semiconductor chip 9 can be easily positioned with respect to the spacer 5 when the semiconductor device 1 is manufactured, the manufacturing efficiency of the semiconductor device 1 can be improved and the spacer 5 and the semiconductor chip can be improved. The yield of 9 can be improved.
In addition, the structure of these engagement recessed parts 45 and 75 is applicable not only to the spacer 5 shown to FIGS. 1-13 but each spacer 52,54,59,63 shown to FIGS.

Furthermore, although the holes 27, 29, 31 and the large diameter hole 57 formed in the base substrate 21, the first film layer 23, and the second film layer 25 are formed in a substantially circular shape in plan view, However, the present invention is not limited to this, and it is sufficient that it is formed so as to penetrate at least the base substrate 21, the first film layer 23, and the second film layer 25 in the thickness direction. Therefore, the holes 27, 29, 31 and the large-diameter hole 57 may be formed in, for example, a substantially rectangular shape, a polygonal shape, an elliptical shape or the like in plan view.
Further, all the spacers 5, 52, 54, 59, 63 described above are arranged on the surface 3a of the circuit board 3. However, the present invention is not limited to this. For example, on the surface of the package in which the circuit is incorporated. It may be arranged. That is, the semiconductor device may be configured using the package instead of the circuit board 3.
Furthermore, although the semiconductor chip 9 is composed of a sound pressure sensor chip provided with the diaphragm 9 a, the present invention is not limited to this, and it is sufficient that the semiconductor chip 9 has at least a movable part such as the diaphragm 9 a constituting the semiconductor chip 9. Therefore, the semiconductor chip may be, for example, a pressure sensor chip that measures the pressure or pressure change in the outer space of the semiconductor device 1.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

1 is a side sectional view showing a semiconductor device according to an embodiment of the present invention. FIG. 2 is a plan view showing a spacer in the semiconductor device of FIG. 1. It is AA arrow sectional drawing of FIG. It is a BB arrow sectional view of Drawing 2. It is a top view which shows the base substrate used for the spacer shown in FIG. It is CC sectional view taken on the line of FIG. It is a top view which shows the state which formed the 1st film layer on the surface of the base substrate shown in FIG. It is DD sectional view taken on the line of FIG. It is EE arrow sectional drawing of FIG. FIG. 2 is a side cross-sectional view showing a method for manufacturing the semiconductor device of FIG. 1. FIG. 2 is a side cross-sectional view showing a method for manufacturing the semiconductor device of FIG. 1. It is a sectional side view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention. It is a top view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention. It is a sectional side view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention. It is a sectional side view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention. It is a sectional side view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention. It is a sectional side view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention. It is a sectional side view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention. It is a sectional side view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Semiconductor device, 3 ... Circuit board, 3a ... Surface, 5, 52, 54, 59, 63 ... Spacer, 5a ... Surface, 9 ... Semiconductor chip, 9a ... Diaphragm, 17 ... through hole, 19, 55 ... communication hole, 21 ... base substrate, 21a ... surface, 23 ... first film layer, 23a ... surface, 25. .... Second film layer, 25b ... back side, 33, 53 ... notch, 45 ... engagement recess, S1 ... hollow space (outer space), S2 ... cavity

Claims (10)

A circuit board or a package incorporating a circuit; a semiconductor chip provided on a surface of the circuit board or the package and having a thin film diaphragm that vibrates according to pressure fluctuation; the circuit board or the package; A substantially plate-like spacer fixed between the semiconductor chips,
2. A semiconductor device according to claim 1, wherein a through hole is formed in the spacer so that the surface of the circuit board or the package and the diaphragm face each other. The spacer is
The flow of gas based on the static pressure difference between the cavity defined by the surface of the circuit board or the package, the diaphragm and the through hole and the outer space located on the outer side of the cavity is allowed. ,
2. The semiconductor device according to claim 1, wherein the semiconductor device prevents passage of gas based on dynamic pressure fluctuation acting on the diaphragm.   The semiconductor device according to claim 1, wherein the spacer is made of a porous body.   The semiconductor device according to claim 1, wherein a communication hole is formed in the spacer. The spacer includes a substantially plate-like base substrate, a thin film-like first film layer formed on the surface of the base substrate, and a thin film-like second film formed on the surface of the first film layer. With layers,
The communication hole is defined by a slit-shaped notch formed in the first film layer, and a surface of the base substrate and a back surface of the second film layer facing each other through the notch. The semiconductor device according to claim 4.   The semiconductor device according to claim 1, wherein the spacer is formed to be elastically deformable.   The semiconductor device according to claim 1, wherein the spacer has a thermal expansion coefficient close to that of the semiconductor chip. The spacer is formed with an engagement recess that is recessed from the surface facing the semiconductor chip,
The semiconductor device according to claim 1, wherein the semiconductor chip is attached to the spacer by engaging with the engaging recess. It is fixed between a circuit board or a package in which a circuit is incorporated and a semiconductor chip having a thin film diaphragm that vibrates in response to pressure fluctuations, and the circuit board or the surface of the package and the diaphragm face each other. A manufacturing method of a spacer having a through hole to be made,
A first thin film forming step of forming a thin film-like first film layer that can be etched on the surface of a substantially plate-like base substrate;
Etching is performed on the first film layer, and the first film layer is slit-shaped from the surface so as to reach the end of the surface along the surface of the base substrate from the through hole. An etching process for forming a notch of
A second thin film formation that forms a thin film-like second film layer on the surface of the first film layer so as to form a communication hole that covers the cutout portion and communicates from the through hole to the end portion. And a step of manufacturing the spacer. A circuit board or a package incorporating a circuit; a semiconductor chip provided on a surface of the circuit board or the package and having a thin film diaphragm that vibrates according to pressure fluctuation; the circuit board or the package; A substantially plate-like spacer fixed between semiconductor chips, and a method of manufacturing a semiconductor device, wherein a through-hole is formed in the spacer so that the surface of the circuit board or the package and the diaphragm face each other. ,
The spacer is
A first thin film forming step of forming a thin film-like first film layer that can be etched on the surface of a substantially plate-like base substrate;
Etching is performed on the first film layer, and the first film layer is slit-shaped from the surface so as to reach the end of the surface along the surface of the base substrate from the through hole. An etching process for forming a notch of
A second thin film formation that forms a thin film-like second film layer on the surface of the first film layer so as to form a communication hole that covers the cutout portion and communicates from the through hole to the end portion. A method for manufacturing a semiconductor device, characterized by being manufactured by a process.

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