JP5665797B2 - PACKAGE FOR PRESSURE SENSOR, MANUFACTURING METHOD THEREOF, AND PRESSURE SENSOR - Google Patents

Description

  The present invention relates to a capacitance type pressure sensor package for detecting pressure, a manufacturing method thereof, and a pressure sensor.

  Conventionally, a capacitance type pressure detection device is known as a pressure detection device for detecting pressure. As described in Patent Document 1 below, a package used in this capacitance type pressure detection device includes an insulating base having a mounting portion on which a semiconductor element is mounted, and a static electricity formed on the surface of the insulating base. A first electrode for forming a capacitance, a diaphragm joined in a flexible state to the surface of an insulating substrate, and a capacitor for forming a capacitance deposited on the surface of the diaphragm so as to face the first electrode The second electrode. In order to form a capacitance by the first electrode and the second electrode, it is necessary to provide a predetermined interval between these electrodes, and a frame-like spacer is provided between the diaphragm and the insulating base. . Then, a sealed space is formed by the insulating base, the spacer, and the diaphragm, and the diaphragm is flexible in accordance with the fluctuation of the external pressure, whereby the change in the distance between the first electrode and the second electrode is changed. Can be made.

  In the pressure detection device package in Patent Document 1 below, an insulating base, a spacer, and a diaphragm are integrally formed.

  Such a package for a pressure detection device is formed by laminating a ceramic green sheet for an insulating substrate, a ceramic green sheet for a spacer, and a ceramic green sheet for a diaphragm, and has a sealed space inside. A ceramic green sheet laminate is formed and is sintered and integrated by firing.

JP 2006-47327 A

  However, when the ceramic green sheet laminate described above is fired, a sealed space is formed at the same time as the sintering integration by firing, so that the pressure in the internal space can be adjusted according to the use after firing, It was impossible to fill the desired gas as needed.

In addition, when firing the ceramic green sheet laminate that constitutes the pressure sensor package, since the sintering is performed in a state where the space is sealed, the gas in the space expands or the gas released from the ceramic green sheet is expanded in the space. In some cases, the diaphragm is deformed at the time of firing and the distance between the first electrode and the second electrode is increased.
In particular, in recent years, the area of the first electrode and the second electrode has been reduced with the miniaturization of the package for the pressure detection device, and the distance between the first electrode and the second electrode is larger than the expected one. When it becomes wider, there is a possibility that the rate of change due to fluctuations in the external pressure is reduced and the external pressure cannot be detected with high sensitivity.

The present invention has been devised in view of the above-described problems of the prior art, and an object thereof is to provide a pressure sensor package and a pressure sensor that can detect external pressure with high sensitivity.
Moreover, it is providing the manufacturing method of the package for pressure sensors.

The pressure sensor package according to the present invention includes a diaphragm, an insulating base, and a spacer provided between the diaphragm and a through hole, and a portion of the diaphragm that overlaps the through hole inside the spacer. upper electrodes but a flexible region, which is provided with an insulating structure having an internal space with the diaphragm and the insulating substrate surrounded by said spacer, the upper side of the inner wall facing each other in the vertical direction of the inner space and a lower electrode provided on the lower side, at least one of the upper or lower side of the inner wall surface, the package pressure sensor having a flexible region that flexible when the external pressure is applied a is, around the area of the inner space in a plan view in insulating structure from the top or bottom, the gap portion is formed to extend from the inner space to the outer surface of the insulating structure And it is characterized in that the recess on the lower side of the air gap portion is provided.

  Preferably, the gap is sealed with a sealing material.

Pressure package sensor of the present invention, around the area of the upper or inner space of the insulating structure in a plan view from the bottom, and the void portion is formed extending from the inner space to the outer surface of the insulating structure, the air gap A recess is provided on the lower side of the part . Therefore, unlike the pressure sensor package which is not formed with a gap and is made of an insulating structure in which the internal space is sealed in advance, the state in the internal space of the insulating structure is changed as necessary. be able to. For example, by making the internal space in a vacuum state, the dielectric constant between the upper electrode and the lower electrode can be lowered. If the pressure sensor is planned to be used in an extremely high pressure environment, the internal space can be made sufficiently higher than the atmospheric pressure, and helium gas or other gas can be filled if necessary. You can also keep it. Further, as compared with the case where a gap is formed in the flexible region, it is possible to suppress variation in the bending of the flexible region when an external pressure is applied.

  Moreover, since the space | gap part is sealed with the sealing material, it can be set as the package for pressure sensors which has the internal space sealed in the state as needed.

It is a top view which shows an example of embodiment of the package for pressure sensors of this invention. (A) is sectional drawing in the A-A 'line of FIG. 1, (b) is sectional drawing of the pressure sensor of this invention based on (a). It is an exploded top view which shows an example of embodiment of the insulation base | substrate of the package for pressure sensors of this invention. It is an exploded top view which shows an example of embodiment of the spacer of the package for pressure sensors of this invention. It is a decomposition | disassembly bottom view which shows an example of embodiment of the diaphragm of the package for pressure sensors of this invention. It is a top view which shows an example of embodiment of the package for pressure sensors of this invention. (A) is sectional drawing which shows an example of embodiment of the package for pressure sensors of this invention, (b) is sectional drawing of the pressure sensor of this invention based on (a). (A) is sectional drawing which shows an example of embodiment of the package for pressure sensors of this invention, (b) is sectional drawing of the pressure sensor of this invention based on (a).

The package for a pressure detection device of the present invention will be described. FIG. 1 is a plan view showing an example of an embodiment of a pressure sensor package according to the present invention. 2A is a cross-sectional view taken along line AA ′ of FIG. 1, and FIG. 2B is a cross-sectional view of the pressure sensor based on FIG. 2A. In these drawings, 1 is an insulating structure, 2 is an insulating substrate, 3 is a spacer, 4 is a diaphragm, 4a is a flexible region, 5 is a lower electrode, 6 is an upper electrode, 7 is a gap, and 8 is a wiring conductor. , 9 is a sealing material, 10 is an electronic component, 11 is a conductive bonding material, 12 is a sealing resin, and S is an internal space.

  The pressure sensor package of the present invention includes an insulating structure 1 having an internal space S, and an upper electrode 6 and a lower electrode 5 provided on the upper side and the lower side of the inner wall surfaces of the internal space S facing each other. A pressure sensor package in which at least one of the upper side or the lower side of the inner wall surface has a flexible region 4a that is flexible when an external pressure is applied. A gap 7 extending from S to the outer surface of the insulating structure 1 is formed.

  The insulating structure 1 according to the present invention includes, for example, an insulating base 2, a spacer 3, and a diaphragm 4, and an internal space S is formed in the insulating structure 1 by these.

  The insulating base 2, the spacer 3, and the diaphragm 4 are made of an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, a silicon carbide sintered body, a silicon nitride sintered body, a glass-ceramic, etc. It is a laminate made of an electrically insulating material. If the insulating base 2, the spacer 3, and the diaphragm 4 are made of, for example, an aluminum oxide sintered body, they are manufactured as follows. First, a ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide is mixed with a suitable organic binder, solvent, plasticizer, and dispersant to form a slurry, and this is formed into a sheet by the doctor blade method. To obtain a plurality of ceramic green sheets. Thereafter, ceramic green sheets for the insulating base 2, the spacer 3, and the diaphragm 4 are obtained by performing appropriate punching, laminating, and cutting on these ceramic green sheets. Then, the insulating base 2, the spacer 3, and the diaphragm 4 are fired at a temperature of about 1600 ° C. to manufacture the insulating base 2, the spacer 3, and the diaphragm 4.

  The insulating base 2 has a concave portion 1a for accommodating the electronic component 10 on one surface (the lower surface in FIG. 2), and functions as a container for accommodating the electronic component 10. And the mounting part 1b in which the electronic component 10 is mounted is formed in the center part of the bottom face of this recessed part 1a. The electronic component 10 is mounted on the mounting portion 1b, and the electronic component 10 is covered with a resin sealing material 12 such as an epoxy resin in the recess 1a, whereby the electronic component 10 is sealed.

  In this example, the electronic component 10 is sealed by being covered with the resin sealing material 12, but a lid made of metal or ceramic is covered on one surface of the insulating base 2 so as to close the recess 1 a. You may seal by making it join.

  A plurality of wiring conductors 8 that are electrically connected to the respective electrodes of the electronic component 10 are led out to the mounting portion 1b. The wiring conductor 8 and the respective electrodes of the electronic component 10 are electrically conductive, such as solder bumps. It joins via the conductive joining material 12 which consists of material. Thereby, each electrode of the electronic component 10 and each wiring conductor 8 are electrically connected, and the electronic component 10 is fixed to the mounting portion 1b. In the example shown in FIG. 2, the electrode of the electronic component 10 and the wiring conductor 8 are connected via the solder bumps. However, the electrode of the electronic component 10 and the wiring conductor 8 are other than bonding wires or the like. The electrical connection means may be used.

The wiring conductor 8 functions as a conductive path for electrically connecting each electrode of the electronic component 10 to the external electric circuit and the lower electrode 5 and the upper electrode 6, and a part of one of the surfaces of the insulating base 2 (see FIG. 2 is led to the outer peripheral portion of the lower surface, and another part is electrically connected to the lower electrode 5 and the upper electrode 6. And after each electrode of the electronic component 10 is electrically connected to these wiring conductors 8 via a conductive bonding material 11 such as a solder bump and the electronic component 10 is sealed with a resin sealing material 12, A portion led out to the outer peripheral portion of one surface (the lower surface in FIG. 2) of the insulating base 2 of the wiring conductor 8 is bonded to the wiring conductor (not shown) of the external electric circuit board via a conductive bonding material such as solder. By doing so, the electronic component 10 accommodated in the inside is electrically connected to the external electric circuit.

  The wiring conductor 8 is made of metal powder metallization such as tungsten, molybdenum, copper, silver, etc., and is obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, dispersant, etc. to metal powder such as tungsten. The paste is printed and applied in a predetermined pattern on the ceramic green sheet for the insulating substrate 2 by screen printing, and is fired together with the ceramic green sheet for the insulating substrate 2 to form a predetermined pattern on the inside and surface of the insulating substrate 2. It is formed. The exposed surface of the wiring conductor 8 has a thickness so as to prevent the wiring conductor 8 from being oxidatively corroded and to improve the bonding between the wiring conductor 8 and the conductive bonding material 12 such as solder. It is preferable that a nickel plating layer having a thickness of about 1 to 10 μm and a gold plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited.

  A lower electrode 5 for forming a capacitance is attached to the center of the upper surface of the insulating substrate 2. The lower electrode 5 is for forming a capacitance for a pressure sensitive element together with an upper electrode 6 described later, and is formed in a substantially circular pattern, for example. A wiring conductor 8a which is one of a plurality of wiring conductors 8 is connected to the lower electrode 5, and an electrode of an electronic component 10 is connected to a conductive bonding member 12 such as a solder bump on the wiring conductor 8a. Thus, the electrode of the electronic component 10 and the lower electrode 5 are electrically connected.

  The lower electrode 5 is made of metal powder metallization such as tungsten, molybdenum, copper, silver, etc., and is obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, and dispersant to metal powder such as tungsten. Is printed on the ceramic green sheet for the insulating substrate 2 by screen printing and fired together with the ceramic green sheet for the insulating substrate 2 to form a predetermined pattern at the center of the upper surface of the insulating substrate 2.

  The spacer 3 is laminated on the upper surface of the insulating base 2 so as to surround the lower electrode 5. The spacer 3 is made of a ceramic material similar to that of the insulating base 2 and functions as providing a sealed space with a predetermined interval between the insulating base 2 and the diaphragm 4. The outer shape of the spacer 3 is substantially the same as that of the insulating base 2. A circular through hole for forming a sealed space between the insulating base 2 and the diaphragm 4 is formed at the center. If the thickness of the spacer 3 is less than 0.01 mm, the lower electrode 5 and the upper electrode 6 may come into contact with each other and short circuit when the diaphragm 4 is bent under pressure. On the other hand, if it exceeds 5 mm, the distance between the lower electrode 5 and the upper electrode 6 becomes too wide and the sensitivity of the built-in pressure sensitive element becomes low. Therefore, the thickness of the spacer 3 is preferably in the range of 0.01 to 5 mm. Such a spacer 3 is formed by laminating a ceramic green sheet for the spacer 3 having a through hole for the internal space S on the ceramic green sheet for the insulating base 2 and firing them to form an upper surface of the insulating base 2. Sintering is integrated so as to surround the lower electrode 5.

On the upper surface of the spacer 3, a substantially flat diaphragm 4 is sintered and integrated in a flexible state so as to form an internal space S with the insulating base 2. The diaphragm 4 is a substantially rectangular flat plate having a thickness of 0.01 to 5 mm made of a ceramic material similar to that of the insulating base 2, and is a so-called pressure sensor diaphragm that bends toward the insulating base 2 in response to external pressure. Function. In addition, the area | region inside the lamination | stacking area | region 4b with the spacer 3 becomes the flexible area | region 4a (area | region shown inside the long broken line shown in FIG. 1), and this flexible area | region 4a bends according to external pressure. It becomes. In addition, since the diaphragm 4 has a small mechanical strength when the thickness is less than 0.01 mm, the risk of being destroyed when a large external pressure is applied to the diaphragm 4 is large. On the other hand, when it exceeds 5 mm, it becomes difficult to bend with a small pressure, and it becomes unsuitable as a diaphragm for a pressure sensor. Therefore, the thickness of the diaphragm 4 is preferably in the range of 0.01 to 5 mm. The diaphragm 4 is formed by laminating a flat ceramic green sheet for the diaphragm 4 on the ceramic green sheet for the spacer 3 described above, and firing them so that the diaphragm 4 has an internal space between the insulating base 2 and the spacer 3. Sintering is integrated in a flexible state so as to form the space S. As a result, the insulating structure 1 having the internal space S composed of the insulating base 2, the spacer 3, and the diaphragm 4 is integrally formed by sintering.

  A substantially circular upper electrode 6 for forming a capacitance is attached to the lower surface of the diaphragm 4 so as to face the lower electrode 5. The upper electrode 6 functions as an electrode for forming a capacitance for the pressure sensitive element together with the lower electrode 5 described above. Then, another one 8b of the wiring conductor 8 is connected to the upper electrode 6, and when the electrode of the electronic component 10 is connected to the wiring conductor 8b via the conductive bonding member 11 such as a solder bump, the electronic component Ten electrodes and the upper electrode 6 are electrically connected.

  At this time, the lower electrode 5 and the upper electrode 6 are opposed to each other with an internal space S formed between the insulating base 2 and the diaphragm 4 interposed therebetween, and the lower electrode 5 and the upper electrode 6 are interposed therebetween. A predetermined electrostatic capacity is formed in accordance with the area and the distance between the lower electrode 5 and the upper electrode 6. When an external pressure is applied to the upper surface of the diaphragm 4, the flexible region 4a of the diaphragm 4 is bent toward the insulating base 2 in accordance with the pressure, and the interval between the lower electrode 5 and the upper electrode 6 changes. As a result, the capacitance between the lower electrode 5 and the upper electrode 6 changes, so that it functions as a pressure-sensitive element that senses a change in external pressure as a change in capacitance. Then, the change in electrostatic capacity is transmitted to the electronic component 10 accommodated in the recess 1a through the wiring conductors 8a and 8b, and the electronic component 10 performs arithmetic processing to know the magnitude of the external pressure. Can do. The pressure sensor of the present invention can be used under a pressure of 80 Kpa (low pressure sensor) to 2000 Kpa (high pressure sensor).

  The upper electrode 6 is made of metal powder metallization such as tungsten, molybdenum, copper, and silver, and a metallized paste obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, and dispersant to metal powder such as tungsten. The lower electrode 5 is sandwiched between the lower surface of the diaphragm 4 by sandwiching the inner space S by printing and applying to the ceramic green sheet for the diaphragm 4 by adopting a conventionally known screen printing method and firing it together with the ceramic green sheet for the diaphragm 4. Are formed in a predetermined pattern opposite to each other.

  In the present invention, the insulating structure 1 is formed with a gap 7 extending from the internal space S to the outer surface of the insulating structure 1. As shown in FIG. 2 (b), this pressure sensor package has an internal structure by sealing the gap 7 with a sealing material 9 (in FIG. 2, the gap 7 is sealed with an opening). The space S can be sealed. For example, the dielectric constant between the upper electrode 6 and the lower electrode 5 can be lowered by making the internal space S into a vacuum state. Further, when it is planned to be used in an extremely high pressure environment, the internal space S can be sufficiently higher than the atmospheric pressure, and further, a gas such as helium gas can be filled as required. You can also. Thereby, unlike the insulating structure 1 in which the gap 7 is not formed and the internal space S is sealed in advance, the state of the insulating structure 1 in the internal space S is changed as necessary. be able to.

Also, as described above, the ceramic green sheet for the insulating structure 1 is laminated by laminating the ceramic green sheet for the insulating base 2, the ceramic green sheet for the spacer 3, and the ceramic green sheet for the diaphragm 4. When formed, the ceramic green sheet laminate for the insulating structure 1 is preferably provided with a gap 7 formed in advance from the internal space S to the outer surface of the ceramic green sheet laminate before firing. As a result, the internal space S and the outer surface of the ceramic green sheet laminate for the insulating structure 1 are connected by the gap 7, and the internal space S is fired when the ceramic green sheet laminate for the insulating structure 1 is fired. The internal gas can be released to the outside, and the external air pressure and the internal air pressure can be made close to each other. It can suppress that the bending area | region 4a deform | transforms and the space | interval of the upper side electrode 6 and the lower side electrode 5 becomes wider than what was planned. Thereby, the external pressure can be detected with high sensitivity.

  Further, as the sealing material 9, glass, resin, brazing material or the like can be used. When a brazing material such as Ag-Cu brazing material is used as the sealing material 9, a bonding metal layer (not shown) is provided on the surface of the insulating structure 1 around the gap portion 7. The gap portion 7 can be sealed by joining the brazing material via the metal layer. For example, a metal layer is formed on the surface of the insulating structure 1 along the opening of the opening 7, and a predetermined amount or more of a brazing material is melted on the metal layer to seal the gap 7 with the opening. You should do it. Such a metal layer is obtained by adding a metallized paste obtained by adding and mixing a metal powder metallizing dispersant such as tungsten, molybdenum, copper, silver or the like to the insulating structure 1 by a screen printing method or the like. A predetermined pattern is printed and applied to each ceramic green sheet to be formed and fired together with the ceramic green sheet laminate for the insulating structure 1 to form a predetermined pattern on the surface of the insulating structure 1 around the gap 7. It is formed. When the metal layer for bonding is made of tungsten or molybdenum, the exposed surface of the wiring conductor 8 is nickel having a thickness of about 1 to 10 μm in order to improve the bonding with a brazing material such as Ag—Cu brazing. A plating layer is preferably applied. Further, when a brazing material such as an Ag—Cu brazing material is used as the sealing material 9, the thickness of the surface of the sealing material 9 exposed is the same as that of the wiring conductor 8 in order to suppress the oxidative corrosion of the sealing material 9. It is preferable that a nickel plating layer having a thickness of about 1 to 10 μm and a gold plating layer having a thickness of about 0.1 to 3 μm are sequentially deposited.

  The gap 7 is provided in a region other than the flexible region 4a in which the diaphragm 4 is flexible when an external pressure is applied, for example, in the stacked region 4b in which the diaphragm 4 and the spacer 3 are stacked. It is preferable. Thereby, compared with the case where the space | gap part 7 is formed in the flexible area | region 4a of the diaphragm 4, it is suppressed that dispersion | variation arises in the bending of the diaphragm 4 when an external pressure is applied. Therefore, variation in capacitance detected by the upper electrode 6 and the lower electrode 5 can be suppressed, and external pressure can be detected with high sensitivity.

  3 to 5 are examples of a pressure sensor package in the case where the gap 7 is provided in a region other than the flexible region 4a, and an exploded view of the insulating structure 1 is shown. Here, the gap 7 is provided in the laminated region 4 b of the spacer 3 and the diaphragm 4, FIG. 3 is a top view of the insulating base 2, FIG. 4 is a top view of the spacer 3, and FIG. 5 is a bottom view of the diaphragm 4. (Bottom view from the insulating base 2 side) is shown. In these drawings, the area outside the broken line indicates the respective laminated areas of the insulating base 2, the spacer 3, and the diaphragm 4.

  Moreover, when forming the space | gap part 7 in the diaphragm 4, it is more preferable to form in the wide area | region of the lamination | stacking area | region 4b, for example, as shown in FIG. In addition, if the diaphragm 4 has a quadrangular shape and the flexible region 4a has a circular shape, it is preferable to provide the gap portion 7 at a diagonal position that is a wide region of the stacked region 4b. Thereby, it can suppress that the mechanical strength of the insulating structure 1 falls in the circumference | surroundings of the space | gap part 7. FIG.

In addition, as shown in FIG. 7, a frame 13 may be formed on the upper surface of the diaphragm 4. Such a frame 13 is made of a ceramic material similar to that of the insulating structure 1.
If the frame body 13 is made of, for example, an aluminum oxide sintered body, it is manufactured as follows. First, a ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide is mixed with a suitable organic binder, solvent, plasticizer, and dispersant to form a slurry, and this is formed into a sheet by the doctor blade method. To obtain a plurality of ceramic green sheets. Thereafter, the ceramic green sheet is appropriately punched, laminated, and cut to obtain a ceramic green sheet for the frame 13.
And the frame 13 is manufactured by baking this ceramic green sheet at the temperature of about 1600 degreeC.

  The frame 13 is sintered with the diaphragm 4 by laminating the ceramic green sheet for the frame 13 on the ceramic green sheet for the diaphragm 4 so as to surround the flexible region 4a, and firing them simultaneously. Integration, that is, sintering integration with the insulating structure 1 is performed. Note that the shape of the inner diameter of the frame 13 is preferably circular in plan view. When the frame body 13 is provided on the upper surface of the diaphragm 4, the gap 7 may be opened in the frame body 13 as shown in FIG. 7.

  The ceramic green sheet for the frame 13 is laminated on the ceramic green sheet for the diaphragm 4 and fired, whereby the ceramic green sheet for the diaphragm 4 becomes the ceramic green sheet for the spacer 3 and the frame 13. Since the ceramic green sheets are laminated from above and below, warping of the diaphragm 4 during firing can be suppressed.

  Further, the gap 7 may be provided with a step 7a in its path. FIG. 7 shows an example in which the step 7 a is provided by making the opening diameter of the gap portion 7 formed in the frame 13 larger than the opening diameter of the gap portion 7 formed in the diaphragm 4. . Thereby, when sealing the space | gap part 7 with the sealing material 9, since the sealing material 9 can be arrange | positioned in this level | step-difference part 7a, the sealing material 9 protrudes from the main surface of the insulating structure 1. It becomes easy to suppress, and it becomes easy to make stable the thickness and external shape of the package for pressure sensors. Further, when the gap 7 is opened on the main surface side of the diaphragm 4 and the gap 7 is provided other than the flexible region 4 a, the sealing material 9 flows out to the flexible region 4 a of the diaphragm 4. Therefore, it is possible to suppress the occurrence of distortion in the bending of the diaphragm 4.

Moreover, it is preferable that the sealing material 9 is enclosed in the gap portion 7 and that the gap portion 7 includes a curved portion. In addition, a curved part here means the site | part where the space | gap part 7 extended from the internal space S to the outer surface of the insulating structure 1 is bent in the middle of the path | route. Accordingly, when the sealing material 9 is sealed in the gap portion 7, the sealing material 9 can be stopped at the curved portion, so that the sealing material 9 penetrates into the internal space S and the upper electrode 6 or the lower side. Covering the electrode 5 can be suppressed. Therefore, variation in capacitance detected by the upper electrode 6 and the lower electrode 5 can be suppressed, and external pressure can be accurately detected.

  In addition, as shown in FIG. 8, when the gap 7 is opened on the main surface side of the diaphragm 4 and the gap 7 is provided outside the flexible region 4 a, the insulation corresponding to the back side of the gap 7 is provided. You may provide the recessed part 7b in the upper surface etc. of the base | substrate 2. FIG. Thereby, when sealing, even if a part of the sealing material 9 is torn off and a part of the sealing material 9 that seals the gap 7 flows in, the sealing material 9 is indented. By accommodating in 7b, it can suppress that it penetrates into the interior space S. When a brazing material such as an Ag-Cu brazing material is used as the sealing material 9, if a metal layer for bonding is formed on the bottom surface of the recessed portion 7b, a part of the invading sealing material 9 is recessed. The metal layer formed on the portion 7b can be reliably deposited, and the penetration into the internal space S can be suppressed.

  The diaphragm 4 is made of ceramics containing one or more kinds of metal oxides (metal oxides) selected from Si, Ca, Mg, and Ti, and is included in the ceramics constituting the insulating base 2 and the spacer 3. It is preferable that the weight ratio of the metal oxide contained in the ceramics constituting the diaphragm 4 is higher than the weight ratio (including 0) of the metal oxide.

  From this, the Young's modulus of the diaphragm 4 can be made lower than the Young's modulus of the insulating base 2 and the spacer 3. When an external pressure is applied, the flexible region 4a of the diaphragm 4 having a low Young's modulus is easily deformed, while the insulating base 2 and the spacer 3 having a high Young's modulus are difficult to deform. Therefore, it is possible to obtain an insulating structure having robustness while having a sensitive flexible region. Thereby, an external pressure can be detected with higher sensitivity.

In addition, the weight ratio of a metal oxide here means what is calculated according to the following procedures and the following formula 1. That is, O and each metal (Si, Ca, Mg, Ti) are bonded in the following states (SiO ₂ , CaO, MgO, TiO ₂ ), that is, stoichiometrically bonded. The weight% of metal oxide converted as if it is present (in the case of plural kinds, the weight percentage of the total amount) is calculated.

Next, the weight% (at least one kind or a plurality of kinds of Al ₂ O ₃ , AlN, Si ₃ N _4, etc.) constituting the main crystal phase is calculated (in the case of a plurality of kinds, the weight percentage of the total amount). .

  The following formula: weight ratio of metal oxide = wt% of metal oxide × 100 / wt% of ceramics ... The value calculated according to Formula 1 is referred to as the weight ratio of metal oxide.

  In such an insulating structure 1, if the insulating structure 1 is made of an aluminum oxide sintered body, the diaphragm 4 is made of an aluminum oxide sintered body, and the weight ratio of the metal oxide is 2 to 35. It is good to make it.

  On the other hand, the insulating base 2 and the spacer 3 are made of an aluminum oxide sintered body, and the weight ratio of the metal oxide is preferably 1-15. It is important that the weight ratio of the metal oxide of the diaphragm 4 is larger than the weight ratio of the metal oxide of the insulating base 2 and the spacer 3. Thereby, the pressure sensor which can give sufficient softness | flexibility to the flexible area | region 4a of the diaphragm 4 is obtained. Specifically, the difference between the weight ratio of the metal oxide contained in the diaphragm 4 and the weight ratio of the metal oxide contained in the insulating base 2 and the spacer 3 is preferably 1-20.

  When it is 1 or more, the above-described difference in Young's modulus is sufficient, and a pressure sensor package having flexibility and robustness can be obtained. Moreover, when it is 20 or less, the occurrence of stress strain at the interface between the diaphragm 4 and the spacer 3 can be suppressed, and the airtightness of the internal space S can be maintained well over a long period of time.

  In the above case, the Young's modulus was measured based on JIS R1602 (fine ceramics elastic modulus test method), and the Young's modulus of the aluminum oxide sintered body of the diaphragm 4 was 200 GPa to 400 GPa.

  Further, when the frame body 13 made of ceramics is provided on the upper surface of the diaphragm 4, it is desirable that the Young's modulus of the diaphragm 4 is lower than the Young's modulus of the frame body 13. When the frame 13 is made of ceramics, the weight ratio of the metal oxide of the diaphragm 4 is preferably made higher than the weight ratio of the metal oxide of the frame 13.

  Next, the manufacturing method of the pressure sensor package of the present invention will be described.

  The manufacturing method of the pressure sensor package of the present invention is provided on each of the insulating structure 1 having the internal space S of the pressure sensor package of the present invention and the upper and lower sides of the inner wall surfaces facing each other. The upper electrode 6 and the lower electrode 5 are provided, and at least one of the upper side and the lower side of the inner wall surface has a flexible region 4a that is flexible when an external pressure is applied, and from the inner space S. A manufacturing method for obtaining a pressure sensor package in which a gap 7 extending to the outer surface of an insulating structure 1 is formed. The insulating structure 1 includes a ceramic green sheet in which an internal space S and a gap 7 are provided. It is obtained by firing the laminate.

  In the manufacturing method described above, first, a ceramic green sheet for the insulating substrate 2, a ceramic green sheet for the spacer 3, and a ceramic green sheet for the diaphragm 4 are prepared. Next, a through hole for the wiring conductor 8 and a through hole for the internal space S are formed in these ceramic green sheets by a punching method such as a die or punching or a hole processing method such as laser processing, and the lower electrode 5, A metallized paste for the upper electrode 6 and the wiring conductor 8 is printed and applied. And the through-hole for the space | gap parts 7 is formed in the desired area | region of these ceramic green sheets by the hole processing method similar to the above-mentioned. For example, when forming a pressure sensor package as shown in FIG. 2, a through hole for the gap 7 is formed in each of the ceramic green sheet for the spacer 3 and the ceramic green sheet for the diaphragm 4. good. Then, these ceramic green sheets are arranged and laminated so that the through hole for the internal space S and the through hole for the void portion 7 communicate with each other, whereby the ceramic green for the insulating structure 1 having the void portion 7 is formed. A sheet laminate can be formed. The through hole for the gap 7 may be formed at the same time as the through hole for the wiring conductor 8 or the through hole for the internal space S is formed.

  Also, after laminating the ceramic green sheet for the insulating substrate 2, the ceramic green sheet for the spacer 3, and the ceramic green sheet for the diaphragm 4, a ceramic green sheet laminated body for the insulating structure 1 is formed, and then the laser. The gap 7 may be formed by a processing method such as processing. In addition, when forming the void portion 7, it is possible to reduce the possibility that the processing waste of the ceramic green sheet is inherent in the internal space S, or to easily form the void portion 7 in a shape as necessary (step 7 a, In consideration of the fact that the recesses 7b, the curved portions, etc. are easily formed in a predetermined shape), after the above-described through holes for the gaps 7 are formed in desired regions of the ceramic green sheets, these ceramic green A method of laminating sheets to form the void 7 is preferable.

  When the ceramic green sheet laminate for the insulating structure 1 is formed, the ceramic green sheet for the insulating base 2, the ceramic green sheet for the spacer 3, and the ceramic green sheet for the diaphragm 4 may be laminated at the same time. It may be good or may be laminated individually. When the frame 13 is provided on the upper surface of the diaphragm 4, the ceramic green sheet for the frame 13 is formed into a frame shape using the same hole processing method as described above, and then laminated on the ceramic green sheet for the diaphragm 4. And then fired at the same time.

Moreover, it is preferable that the internal space S of the ceramic green sheet laminate for the insulating structure 1 is filled with a burned-out member that is burned out by the end of firing. For example, as such a burned-out member, a resin sheet or a resin paste that is thermally decomposed during firing can be used. For example, after a through hole for the internal space S is formed in the ceramic green sheet for the spacer 3, a ceramic sheet for the insulating base 2 and the spacer 3 for the spacer 3 are embedded by embedding a resin sheet in the through hole. When the ceramic green sheet and the ceramic green sheet for the diaphragm 4 are laminated, the resin sheet is filled into the internal space S of the ceramic green sheet laminate. Also, a ceramic green sheet for the insulating substrate 2 and a ceramic green sheet for the spacer 3 are laminated, and a resin paste is filled in the recess formed by this by screen printing or the like, and then the ceramic green for the diaphragm 4 is filled. By laminating the sheets, the resin paste is filled in the internal space S of the ceramic green sheet laminate. Thereby, the internal space S is filled with the burned-out member, and the ceramic green sheet laminate is held by the burned-out member. Therefore, the ceramic green sheet laminate is deformed by handling or the like, and the shape of the internal space S is predetermined. It can be suppressed that the shape greatly differs. For example, when the ceramic green sheet for the insulating substrate 2, the ceramic green sheet for the spacer 3, and the ceramic green sheet for the diaphragm 4 are laminated by applying pressure, the ceramic green sheet for the diaphragm 4 has an internal space. Since it is held by the burned-out member filled with S, it is possible to suppress the deformation of the flexible region 4a of the ceramic green sheet of the diaphragm 4 due to the pressure during lamination. In addition, after the ceramic green sheet laminate for the insulating structure 1 is formed, the flexible region 4a of the ceramic green sheet for the diaphragm 4 is held by the burned-out member filled in the internal space S. Thus, deformation can be suppressed. When these burned-out members are baked, the pyrolyzed gas can be discharged well from the gap 7, so that the diaphragm 4 is prevented from being deformed by the gas generated when pyrolyzed. it can. Therefore, the shape of the internal space S of the insulating structure 1 can be improved, the distance between the upper electrode 6 and the lower electrode 5 can be formed with higher accuracy, and the external pressure can be detected with high sensitivity. It can be set as the package for pressure sensors.

  The burnout member may be filled in a region other than the internal space S of the ceramic green sheet laminate for the insulating structure 1, that is, in the gap 7. Even in this case, the same effect as in the case of the internal space S can be obtained.

  The ceramic green sheet for the diaphragm 4 includes one or more kinds of metal oxides (metal oxides) selected from Si, Ca, Mg, and Ti, and is included in the ceramic green sheet for the spacer 3. The weight ratio of the metal oxide contained in the ceramic green sheet for the diaphragm 4 is preferably higher than the weight ratio (including 0) of the metal oxide. When the ceramic green sheet laminate is fired, the ceramic green sheet for the diaphragm containing more metal oxide components starts to contract before the ceramic green sheet for the spacer. Accordingly, the ceramic green sheet for the diaphragm can be fired while the ceramic green sheet for the spacer is pulled. Thereby, the ceramic green sheet for the spacer was fired in a state in which the ceramic green sheet for the diaphragm was pressed, as in the case where the ceramic green sheet for the spacer contracted before the ceramic green sheet for the diaphragm. As a result, it is possible to suppress the diaphragm from being baked in a curved shape. Alternatively, the degree of bending can be reduced. Therefore, the shape of the internal space S of the insulating structure 1 can be improved, the distance between the upper electrode 6 and the lower electrode 5 can be formed with higher accuracy, and the external pressure can be detected with high sensitivity. It can be set as the package for pressure sensors.

For example, when the insulating structure 1 is made of an aluminum oxide sintered body, the ceramic green sheet for the spacer 3 and the ceramic green sheet for the diaphragm 4 are made of aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, or the like. An appropriate organic binder, a solvent, a plasticizer, and a dispersant are added to and mixed with the ceramic raw material powder to form a slurry, which is then formed into a sheet by the doctor blade method. At this time, the weight ratio of one or more kinds of metal oxides (metal oxides) selected from Si, Ca, Mg, Ti added to the ceramic green sheet for the diaphragm 4 (definition and calculation method is as described above. ) May be added so as to be higher than the weight ratio of the metal oxide of the ceramic green sheet for the spacer 3. When the insulating structure 1 is made of an aluminum oxide sintered body, the SiO ₂ contained in the ceramic green sheet for the diaphragm 4 may be 2 to 35 by weight ratio. Further, the SiO ₂ contained in the ceramic green sheet for the spacer 3 may be 1 to 15 by weight ratio.

  When the frame 13 is provided on the upper surface of the diaphragm 4, the weight ratio of the metal oxide contained in the ceramic green sheet for the diaphragm 4 is greater than the weight ratio of the metal oxide contained in the ceramic green sheet for the frame 13. Is preferably high. In this case, a ceramic green sheet similar to the ceramic green sheet for the spacer 3 is used as the ceramic green sheet for the frame 13. The ceramic green sheet for the insulating substrate 2 is a ceramic green sheet similar to the ceramic green sheet for the spacer 3.

  The pressure sensor of the present invention includes a pressure sensor package of the present invention or a pressure sensor package obtained by the manufacturing method of the present invention, a sealing material S enclosed in a gap 7 of the pressure sensor package, and a pressure sensor. And an electronic component 10 mounted in a package for use. Thereby, it can be set as the pressure sensor which can detect an external pressure with sufficient sensitivity.

  Note that the electrostatic capacitance formed by the upper electrode 6 and the lower electrode 5 is transmitted to the electronic component 10 via the wiring conductors 8a and 8b. And the magnitude | size of an external pressure can be known by computing this with the electronic component 10. FIG.

  When the electronic component 10 is a flip chip type, the electrodes and wiring conductors of the electronic component 10 are connected via solder bumps, gold bumps, or conductive resin (anisotropic conductive resin, etc.). When the electronic component 10 is a wire bonding type, the electronic component 10 is fixed by a bonding material such as glass, resin, brazing material, etc., and then the electronic component is connected via a bonding wire. This is performed by electrically connecting the ten electrodes and the wiring conductor 8. Further, the pressure sensor package may be equipped with an electronic component 10 such as an acceleration sensor, if necessary, in addition to the arithmetic processing electronic component 10 described above.

  The electronic component 10 is sealed by covering the electronic component with a sealing resin such as an epoxy resin, or a lid made of resin, metal, ceramics or the like placed so as to cover the electronic component is made of glass, It is sealed by being attached to the pressure sensor package with an adhesive such as resin or brazing material.

  The present invention can be variously modified without departing from the gist of the present invention. For example, in the above description, the insulating base 2 includes the concave portion 1a for accommodating the electronic component 10 on the lower side, but the insulating base 2 may be flat. In the pressure sensor package according to the present invention, the internal space S is hermetically sealed by sealing the gap 7, but the resin, metal, ceramics, or the like placed so as to cover the gap 7 is used. The inner space S may be made airtight by attaching and sealing the resulting lid with an adhesive such as glass, resin, or brazing material. Further, the insulating base 2, the spacer 3, the diaphragm 4, and the frame 13 may each be composed of a plurality of ceramic green sheets, and these ceramic green sheets may be subjected to processing such as lamination processing as necessary. It may be given.

DESCRIPTION OF SYMBOLS 1 ... Insulating structure 2 ... Insulating base | substrate 3 ... Spacer 4 ... Diaphragm 4a ... Flexible area 5 ... Lower electrode 6 ... Upper electrode 7 ... Gap part 8 ... Wiring conductor 9 ... Sealing material 10 ... Electronic component 11 ... Conductive bonding material 12 ... Sealing resin S ... Internal space

Claims (2)

A diaphragm, an insulating base, and a spacer provided between the diaphragm and a through hole; a portion of the diaphragm that overlaps the through hole inside the spacer is a flexible region; and the diaphragm And an insulating structure having an internal space surrounded by the insulating base and the spacer ,
And a lower electrode provided on the upper electrode and lower provided on the upper side of the inner wall facing each other in the vertical direction of the inner space, at least one of the upper or lower side of the inner wall surface, from the outside a package pressure sensor having a flexible region that flexible when pressure is applied,
In the region around the inner space of the insulating structure in a plan view from above or below, the gap extending from the inner space to the outer surface of the insulating structure is formed, under the airspace A package for a pressure sensor , wherein a recess is provided on the side .   The pressure sensor package according to claim 1, wherein the gap is sealed with a sealing material.

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