JP4794072B2 - Package for pressure detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure detection device package used in a pressure detection device for detecting pressure.
[0002]
[Prior art]
Conventionally, a capacitance type pressure detection device is known as a pressure detection device for detecting pressure. For example, as shown in a cross-sectional view in FIG. 2, the capacitance type pressure detection device is accommodated in a capacitance type pressure sensitive element 22 and a package 28 on a wiring substrate 21 made of a ceramic material or a resin material. And a semiconductor element 29 for operation. The pressure sensitive element 22 is made of, for example, an electrically insulating material such as a ceramic material, and has an insulating base 24 having a concave portion in which one electrode 23 for forming a capacitance is attached at the center of the upper face, and an upper face of the insulating base 24 The insulating plate 26 is joined in a flexible state so as to form a sealed space with the insulating base 24, and the other electrode 25 for forming a capacitance is attached to the lower surface, and each static plate Consists of external lead terminals 27 for electrically connecting the electrodes 23 and 25 for capacitance formation to the outside, and each capacitance is formed by bending the insulating plate 26 in response to external pressure. The capacitance formed between the electrodes 23 and 25 for use changes. Then, the external pressure can be detected by performing arithmetic processing on the change in the electrostatic capacitance by the semiconductor element 29 for arithmetic operation.
[0003]
[Problems to be solved by the invention]
However, according to this conventional pressure detection device, since the pressure sensitive element 22 and the semiconductor element 29 are individually mounted on the wiring board 21, the pressure detection device becomes large and the pressure detection electrode 23 is increased. The wiring between 25 and the semiconductor element 29 becomes long, and an unnecessary electrostatic capacity is formed between the long wiring, so that the sensitivity is low.
[0004]
Therefore, the applicant of the present application previously described in Japanese Patent Application No. 2000-178618, an insulating base having a mounting portion on which one of the semiconductor elements is mounted on one main surface, and the surface and the inside of the insulating base. A plurality of wiring conductors to which each electrode of the element is electrically connected, and a capacitance formation that is attached to the central portion of the other main surface of the insulating base and is electrically connected to one of the wiring conductors An insulating plate joined in a flexible state so as to form a sealed space between the first electrode for use and the other main surface of the insulating base and the central portion of the main surface, and an inner side of the insulating plate Proposed a pressure sensing device package comprising a second electrode for forming a capacitance that is attached to the main surface facing the first electrode and is electrically connected to the other one of the wiring conductors did. According to this pressure detection device package, the first electrode for forming a capacitance is provided on the other main surface of the insulating base having the mounting portion on which the semiconductor element is mounted on one main surface. Because the insulating plate having the second electrode for forming the opposing capacitance on the inner main surface is joined in a flexible state so as to form a sealed space with the other main surface of the insulating base. The pressure-sensitive element is integrally formed in the package that accommodates the semiconductor element. As a result, the pressure detection device can be reduced in size, and the wiring for connecting the pressure detection electrode and the semiconductor element can be shortened. Unnecessary capacitance generated between the wirings can be reduced. In the pressure detection device package proposed in Japanese Patent Application No. 2000-178618, for example, a frame made of ceramics or metal is provided on the outer peripheral portion of the other main surface of the insulating base so as to surround the first electrode. The insulating plate was joined to the insulating base by brazing the outer peripheral portion of the second electrode onto the frame through a brazing material such as silver-copper brazing.
[0005]
However, according to the package for a pressure detection device proposed in Japanese Patent Application No. 2000-178618, the brazing material made of silver-copper brazing that joins the insulating base and the insulating plate is likely to be plastically deformed by a large stress. When an external pressure is applied to the brazing material for a long period of time, the stress generated by the bending of the insulating plate acts greatly on the inner peripheral edge of the brazing material joining the insulating base and the insulating plate, and the brazing material is plastically deformed. As a result, even if the application of pressure is released, the insulating plate does not return completely to the original position, and the external pressure cannot be accurately detected. It was.
[0006]
The present invention has been completed in view of the above-described problems, and an object of the present invention is to provide a pressure detection device capable of accurately detecting an external pressure over a long period of time.
[0007]
[Means for Solving the Problems]
The package for a pressure detecting device of the present invention has a plurality of wiring conductors inside and on the surface, and a mounting portion on which a semiconductor element is mounted on one main surface, and is electrically connected to one of the wiring conductors on the other main surface. An insulating substrate having a first electrode for forming capacitance connected and a frame-shaped first bonding metallization layer surrounding the first electrode and electrically connected to the other one of the wiring conductors; A second electrode for forming a capacitance facing the first electrode on the main surface, and a frame-like second metallization for bonding that is electrically connected to the second electrode and brazed to the metallization layer for the first bonding A pressure detecting device package comprising: an insulating plate having a layer and an insulating plate joined to the insulating substrate in a flexible state so as to form a sealed space with the other main surface of the insulating substrate; Has a frame-shaped projection on the outer periphery of one of its main surfaces. Rutotomoni is characterized in that the second bonding metallization layer is deposited and formed at a position spaced above 0.05mm from the inner peripheral edge of the protrusion main surface.
[0008]
According to the package for a pressure detection device of the present invention, a frame-shaped protrusion is formed on the outer peripheral portion of one main surface of the insulating plate, and at a position separated by 0.05 mm or more from the inner periphery of the main surface of the protrusion. Since the second bonding metallized layer brazed to the first bonding metallized layer of the insulating substrate is attached, the insulating plate is bent even when a large external pressure is applied to the insulating plate for a long period of time. The stress generated by this is greatly concentrated in the vicinity of the inner peripheral root of the protrusion, and does not act greatly on the inner peripheral edge of the brazing material that joins the insulating base and the insulating plate.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an example of an embodiment of a pressure detection device package according to the present invention, in which 1 is an insulating substrate, 2 is an insulating plate, and 3 is a semiconductor element.
[0010]
The insulating substrate 1 is a laminated body made of a ceramic material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, or glass-ceramics. For example, the insulating substrate 1 is made of an aluminum oxide sintered body. If there is, add a suitable organic binder, solvent, plasticizer, and dispersant to ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, etc. Are formed into a sheet shape to obtain a plurality of ceramic green sheets, and then these ceramic green sheets are subjected to appropriate punching, laminating, and cutting processes to produce a raw ceramic for the insulating substrate 1. A green body is obtained by firing this green ceramic body at a temperature of about 1600 ° C. Made.
[0011]
The insulating base 1 is formed with a recess 1a for accommodating the semiconductor element 3 at the center of the lower surface thereof, thereby functioning as a container for accommodating the semiconductor element 3. The central portion of the bottom surface of the recess 1a is a mounting portion 1b on which the semiconductor element 3 is mounted. The semiconductor element 3 is mounted on the mounting portion 1b and the resin sealing such as an epoxy resin is provided in the recess 1a. The semiconductor element 3 is sealed by filling the material 4. In this example, the semiconductor element 3 is sealed by filling the recess 1a with a resin sealing material 4. However, the semiconductor element 3 has a lid made of metal or ceramics on the lower surface of the insulating base 1 to form the recess 1a. It may be sealed by bonding so as to block.
[0012]
Also, a plurality of metallized wiring conductors 5 connected to the respective electrodes of the semiconductor element 3 are led out to the mounting portion 1b. The metallized wiring conductor 5 and the respective electrodes of the semiconductor element 3 are connected to a conductive material such as a solder bump 6 or the like. The electrodes of the semiconductor element 3 and the metallized wiring conductors 5 are electrically connected to each other through the conductive bonding member made of the semiconductor element 3 and the semiconductor element 3 is fixed to the mounting portion 1b. In this example, the electrode of the semiconductor element 3 and the metallized wiring conductor 5 are connected via the solder bumps 6. However, the electrode of the semiconductor element 3 and the metalized wiring conductor 5 are connected to other types of electric wires such as bonding wires. It may be connected by a general connection means.
[0013]
The metallized wiring conductor 5 functions as a conductive path for electrically connecting each electrode of the semiconductor element 3 to an external electric circuit and a first electrode 7 and a second electrode 9 to be described later. It leads to the outer peripheral lower surface, and another part is electrically connected to the first electrode 7 and the second electrode 9. Each electrode of the semiconductor element 3 is electrically connected to these metallized wiring conductors 5 through a conductive bonding material and the semiconductor element 3 is sealed with a resin sealing material 4. The part led out to the lower surface of the outer periphery of the insulating substrate 1 is joined to the wiring conductor of the external electric circuit board via a conductive bonding material such as solder, so that the semiconductor element 3 accommodated therein is electrically connected to the external electric circuit. The Rukoto.
[0014]
Such a metallized wiring conductor 5 is made of metal powder metallization such as tungsten, molybdenum, copper, and silver, and is obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, dispersant, and the like to metal powder such as tungsten. The metallized paste is printed and applied in a predetermined pattern on a ceramic green sheet for the insulating substrate 1 using a well-known screen printing method, and is fired together with a green ceramic molded body for the insulating substrate 1 to thereby form the insulating substrate 1. A predetermined pattern is formed inside and on the surface. In order to prevent the metallized wiring conductor 5 from being oxidized and corroded on the surface of the metallized wiring conductor 5 and to improve the bonding between the metalized wiring conductor 5 and a conductive bonding material such as solder, it is usual. If present, 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.
[0015]
A first electrode 7 for forming a capacitance is attached to the center of the upper surface of the insulating substrate 1. The first electrode 7 is for forming a capacitance for a pressure sensitive element together with a second electrode 9 described later, and is formed in a substantially circular pattern, for example. The first electrode 7 is connected to one of the metallized wiring conductors 5a, whereby the electrode of the semiconductor element 3 is connected to the metallized wiring conductor 5a via a conductive bonding material such as a solder bump 6. Then, the electrode of the semiconductor element 3 and the first electrode 7 are electrically connected.
[0016]
Such a first electrode 7 is made of metal powder metallization such as tungsten, molybdenum, copper, and silver having a thickness of about 10 to 50 μm, and an appropriate organic binder, solvent, plasticizer, and dispersant are applied to the metal powder such as tungsten. The metallized paste obtained by adding and mixing is printed on a ceramic green sheet for the insulating substrate 1 by employing a conventionally well-known screen printing method, and is fired together with the green ceramic molded body for the insulating substrate 1 to thereby insulate the insulating substrate. 1 is formed in a predetermined pattern in the central portion of the upper surface of 1. In addition, in order to prevent the first electrode 7 from being oxidatively corroded, a nickel plating layer having a thickness of about 1 to 10 μm is usually applied to the surface of the first electrode 7.
[0017]
In addition, a substantially circular or substantially octagonal frame-shaped first bonding metallization layer 8 surrounding the first electrode 7 is attached to the outer peripheral portion of the upper surface of the insulating substrate 1. The first bonding metallization layer 8 functions as a base metal for bonding the insulating plate 2 to the insulating substrate 1. The first bonding metallization layer 8 has a second electrode 9 on the lower surface and a second electrode 9 on the lower surface. An insulating plate 2 having a second bonding metallization layer 10 electrically connected is brazed to the second bonding metallization layer 10 and the first bonding metallization layer 8 via a brazing material 11 such as silver-copper brazing. It is joined by doing.
[0018]
One metallized wiring conductor 5b is connected to the first metallizing layer 8 for bonding, whereby the electrode of the semiconductor element 3 is connected to the metallized wiring conductor 5b via a conductive bonding material such as a solder bump 6. When electrically connected, the electrode of the semiconductor element 3 and the second electrode 9 are electrically connected.
[0019]
The metallization layer 8 for the first bonding is made of metal powder metallization such as tungsten, molybdenum, copper or silver, and an appropriate organic binder, solvent, plasticizer or dispersant is added to and mixed with metal powder such as tungsten. The obtained metallized paste is printed and applied to a ceramic green sheet for the insulating substrate 1 by using a conventionally known screen printing method, and this is fired together with a green ceramic molded body for the insulating substrate 1 to obtain the outer periphery of the upper surface of the insulating substrate 1. A predetermined frame-like pattern is formed on the part.
[0020]
The first bonding metallization layer 8 is prevented from being oxidized and corroded on the surface of the first bonding metallization layer 8 and the bonding between the first bonding metallization layer 8 and the brazing material is strengthened. Further, usually, a nickel plating layer having a thickness of about 1 to 10 μm is applied.
[0021]
The insulating plate 2 attached to the upper surface of the insulating substrate 1 is substantially square or substantially made of a ceramic material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, or glass-ceramics. It is a substantially flat plate such as an octagon or a circle, and has a frame-like protrusion 2a on the outer peripheral portion of the main surface on the insulating base 1 side. Then, it functions as a so-called pressure detecting diaphragm that bends toward the insulating base 1 according to the external pressure.
[0022]
In addition, since the mechanical strength of the insulating plate 2 is small when the thickness of the central portion is less than 0.01 mm, there is a high risk of destruction when a large external pressure is applied thereto. On the other hand, if the thickness of the central portion exceeds 5 mm, it becomes difficult to bend with a small pressure, making it unsuitable as a pressure detecting diaphragm. Therefore, the thickness of the central portion of the insulating plate 2 is preferably in the range of 0.01 to 5 mm. Further, if the height of the protrusion 2a is less than 0.01 mm, the gap formed between the insulating base 1 and the insulating plate 2 becomes too narrow, and the first electrode is applied when pressure is applied to the insulating plate 2. On the other hand, if the height of the protrusion 2a exceeds 5 mm, the static electricity formed between the first electrode 7 and the second electrode 9 is increased. The capacitance becomes small and the sensitivity of the pressure sensitive element is lowered. Therefore, the height of the protrusion 2a is preferably in the range of 0.01 to 5 mm.
[0023]
If such an insulating plate 2 is made of, for example, an aluminum oxide sintered body, a suitable organic binder, solvent, plasticizer, dispersion for ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, etc. A ceramic green sheet is obtained by adding an agent and mixing it into a mud and forming it into a sheet using the well-known doctor blade method, and then punching or cutting the ceramic green sheet appropriately. The raw ceramic molded body for the insulating plate 2 is obtained by processing, and the raw ceramic molded body is manufactured by firing at a temperature of about 1600 ° C.
[0024]
Further, a second electrode 9 for forming a capacitance facing the first electrode 7 is attached to the lower surface of the insulating plate 2 at the center thereof. The second electrode 9 is for forming a capacitance for the pressure sensitive element together with the first electrode 7 described above, and is formed in a substantially circular pattern, for example.
[0025]
Such a second electrode 9 is made of metal powder metallization of tungsten, molybdenum, copper, silver or the like having a thickness of about 10 to 50 μm, and an appropriate organic binder, solvent, plasticizer, or dispersant is applied to the metal powder such as tungsten. The metallized paste obtained by addition and mixing is applied to a ceramic green sheet for the insulating plate 2 by employing a conventionally known screen printing method, and is fired together with the green ceramic molded body for the insulating plate 2 to synthesize the insulating plate. 2 is formed in a predetermined pattern at the center of the lower surface. In addition, in order to prevent the second electrode 9 from being oxidatively corroded, a nickel plating layer having a thickness of about 1 to 10 μm is usually applied to the surface of the second electrode 9.
[0026]
Furthermore, a substantially circular or substantially octagonal frame-shaped second bonding metallization layer 10 electrically connected to the second electrode 9 is formed on the lower surface of the protrusion 2a of the insulating plate 2 by 0.05 mm from the inner periphery of the protrusion 2a. It is attached to the positions separated as described above. The second bonding metallization layer 10 functions as a bonding base metal layer for bonding the insulating plate 2 to the insulating substrate 1, and the second bonding metallization layer 10 and the first bonding metallization layer 8 are silver- By brazing via a brazing material 11 such as copper brazing, the insulating substrate 1 and the insulating plate 2 are joined, and the first joining metallized layer 8 and the second joining metallized layer 10 are electrically connected. The
[0027]
At this time, the first electrode 7 and the second electrode 9 are opposed to each other with a sealed space formed between the insulating base 1 and the insulating plate 2 interposed therebetween. A predetermined capacitance is formed according to the area of the second electrode 9 and the distance between the first electrode 7 and the second electrode 9. When an external pressure is applied to the upper surface of the insulating plate 2, the insulating plate 2 bends toward the insulating base 1 in accordance with the pressure, and the interval between the first electrode 7 and the second electrode 9 changes. Since the capacitance between the first electrode 7 and the second electrode 9 changes, 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 semiconductor element 3 accommodated in the recess 1a through the metallized wiring conductors 5a and 5b, and this is processed by the semiconductor element 3 so as to know the magnitude of the external pressure. be able to.
[0028]
Further, since the second bonding metallization layer 10 is attached to the lower surface of the protrusion 2a at a distance of 0.05 mm or more from the inner periphery of the protrusion 2a, the insulating plate 2 is greatly bent by external pressure. However, the stress generated by the bending is largely concentrated in the vicinity of the root of the inner periphery of the protrusion 2 a and does not act on the inner peripheral edge of the brazing material 11. Therefore, according to the package for a pressure detection device of the present invention, even when an external pressure is applied to the insulating plate 2 for a long period of time, plastic deformation does not occur in the brazing material 11, and the external pressure is maintained for a long period of time. It is possible to provide a pressure detection device that can accurately detect the pressure.
[0029]
If the metallization layer 10 for second bonding is deposited and formed at a position separated by less than 0.05 mm from the inner periphery of the protrusion 2a, the stress generated when the insulating plate 2 is greatly bent by external pressure. A large risk is applied to the inner peripheral edge of the brazing filler metal 11 to increase the risk of plastic deformation in the brazing filler metal 11, and the stress is greatly applied to the corner between the inner peripheral side surface and the lower surface of the protrusion 2a. As a result, the risk of cracks and chipping in the insulating plate 2 increases. Therefore, the formation position of the second bonding metallization layer 10 is specified at a position spaced 0.05 mm or more from the inner periphery of the protrusion 2a.
[0030]
Such a second bonding metallization layer 10 is made of metal powder metallization such as tungsten, molybdenum, copper, silver, etc. with a thickness of about 10 to 50 μm, and suitable organic binder, solvent, plasticizer, A metallized paste obtained by adding and mixing a dispersant is applied and applied to a ceramic green sheet for the insulating plate 2 using a conventionally known screen printing method, and is fired together with a green ceramic molded body for the insulating plate 2 Thus, a predetermined pattern is formed on the lower surface of the protrusion 2a of the insulating plate 2.
[0031]
In order to prevent the second bonding metallization layer 10 from being oxidatively corroded on the surface of the second bonding metallization layer 10, and to improve the bonding between the second bonding metallization layer 10 and the brazing material 11 Normally, a nickel plating layer having a thickness of about 1 to 10 μm is applied.
[0032]
Thus, according to the package for a pressure detection device of the present invention, the first electrode 7 for forming a capacitance is provided on the other main surface of the insulating base 1 on which the semiconductor element 3 is mounted on one main surface. At the same time, the insulating plate 2 having the second electrode 9 for forming a capacitance facing the first electrode 7 on one main surface is joined in a flexible state so as to form a sealed space between the insulating base 1 and the insulating plate 2. Therefore, the container for housing the semiconductor element 3 and the pressure sensitive element are integrated, and as a result, the pressure detection device can be reduced in size. Further, since the first electrode 7 and the second electrode 9 for forming the capacitance are connected to the semiconductor element 3 through the metallized wiring conductors 5a and 5b provided on the insulating base 1, the first electrode 7 and the second electrode 9 are formed. The electrode 9 can be connected to the semiconductor element 3 at a short distance, and as a result, a highly sensitive pressure detecting device is provided by reducing unnecessary capacitance generated between the metallized wiring conductors 5a and 5b. Can do.
[0033]
In order to bond the insulating plate 2 to the insulating substrate 1, a nickel plating layer having a thickness of about 1 to 10 μm is deposited in advance on the surfaces of the first bonding metallization layer 8 and the second bonding metallization layer 10, respectively. The insulating substrate 1 and the insulating plate 2 are sandwiched between a first bonding metallization layer 8 and a second bonding metallization layer 10 with a brazing material foil made of silver-copper brazing having a thickness of about 10 to 200 μm. A method is used in which the first bonding metallized layer 8 and the second bonding metallized layer 10 are brazed by superimposing and heating them to a temperature of about 850 ° C. in a reducing atmosphere to melt the brazing material foil. .
[0034]
Thus, according to the above-described package for the pressure detection device, the semiconductor element 3 is mounted on the mounting portion 1b, and each electrode of the semiconductor element 3 and the metallized wiring conductor 5 are electrically connected. By sealing, the pressure detection device is small and has high sensitivity.
[0035]
In addition, this invention is not limited to an example of the above-mentioned embodiment, It cannot be overemphasized that a various change is possible if it is a range which does not deviate from the summary of this invention.
[0036]
【The invention's effect】
As described above, according to the package for a pressure detection device of the present invention, a capacitance forming device is formed at the central portion of the other main surface of the insulating substrate having a mounting portion on which a semiconductor element is mounted on one main surface. In addition, an insulating plate having a second electrode for forming a capacitance opposite to the first electrode is joined in a flexible state so as to form a sealed space with the insulating base. Therefore, the pressure-sensitive element is integrally formed in the package that accommodates the semiconductor element. As a result, the pressure detection device can be reduced in size, and the wiring for connecting the pressure detection electrode and the semiconductor element is short. As a matter of fact, unnecessary capacitance generated between these wirings can be made small. Further, a frame-like protrusion is formed on the outer peripheral portion of the inner main surface of the insulating plate, and brazed to the metallization layer for the first bonding of the insulating substrate at a position separated by 0.05 mm or more from the inner peripheral edge of the main surface of the protrusion. Since the second metallization layer for bonding is applied, even if a large external pressure is applied to the insulating plate over a long period of time, the stress generated by the bending of the insulating plate It concentrates in the vicinity of the peripheral root and does not act greatly on the inner peripheral edge of the brazing material that joins the insulating base and the insulating plate. Accordingly, there is provided a pressure detection device capable of accurately detecting external pressure over a long period of time without causing plastic deformation in the brazing material even when external pressure is applied to the insulating plate for a long period of time. can do.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an embodiment of a package for a pressure detection device of the present invention.
FIG. 2 is a cross-sectional view showing a conventional pressure detection device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Insulation base | substrate 2 ... Insulation board 2a ... Projection part 3 ... Semiconductor element 7 ... 1st electrode 8 ... For 1st joining Metallized layer 9 ... second electrode
10 ・ ・ ・ ・ ・ Metalized layer for second bonding
11 Brazing material

Claims (1)

A mounting portion having a plurality of wiring conductors inside and on the surface and mounting a semiconductor element on one main surface, and for forming a capacitance electrically connected to one of the wiring conductors on the other main surface An insulating base having a first electrode and a frame-like first bonding metallization layer surrounding the first electrode and electrically connected to the other one of the wiring conductors; A second electrode for forming a capacitance opposite to each other, and a frame-shaped second bonding metallization layer electrically connected to the second electrode and brazed to the first bonding metallization layer, A package for a pressure detecting device, comprising: an insulating plate joined to the insulating base in a flexible state so as to form a sealed space with the other main surface of the insulating base, the insulating plate being one of the insulating plates When a frame-shaped protrusion is formed on the outer periphery of the main surface of Package for pressure detection device, characterized in that the from the inner periphery of the protrusion portion main surface at a position spaced above 0.05mm second bonding metallization layer is deposited and formed on.

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