JP5870837B2 - Pressure sensor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a pressure sensor configured by joining a semiconductor element to a metal stem having a pressure detection diaphragm, and a method for manufacturing such a pressure sensor, and particularly to a high pressure sensor capable of detecting a high pressure of about 200 to 300 MPa. It is suitable for use.

  Conventionally, as this type of pressure sensor, a metal stem having a diaphragm for pressure detection, a joining member provided on the diaphragm, and an element for detecting distortion of the diaphragm, provided on the joining member, A semiconductor device having a semiconductor element bonded to a diaphragm via a bonding member has been proposed (for example, see Patent Document 1).

Here, conventionally, the semiconductor element is generally made of a silicon semiconductor, and the metal stem is generally made of Kovar, which is a low expansion metal. Here, Kovar is an iron-nickel-chromium alloy having a thermal expansion coefficient of about 53 × 10 ⁻⁷ / ° C. in the range of 20 ° C. to 300 ° C. Moreover, what consists of joining glass etc. was employ | adopted for the joining member.

JP 2000-275128 A

  However, in a high pressure region exceeding 200 MPa, low thermal expansion metal such as the above-mentioned Kovar cannot be used as the metal stem in consideration of pressure resistance and the like because of the reliability of material strength. For this reason, stainless steel (for example, SUS430) which is a high-strength material is used as a metal stem.

However, in this case, the difference in coefficient of thermal expansion between the bonding glass, which is a bonding member, and stainless steel is large, exceeding 50 × 10 ⁻⁷ / ° C. (in the range of 20 ° C. to 300 ° C.). Due to the action of stress, the joining member is cracked or broken, and the semiconductor element is also cracked or broken. Therefore, the semiconductor element cannot be bonded to the metal stem with the conventional bonding member made of bonded glass.

  The present invention has been made in view of the above problems, and in a pressure sensor configured by joining a semiconductor element to a metal stem having a pressure detection diaphragm, heat caused by a difference in thermal expansion between the joining member and the metal stem is provided. An object of the present invention is to reduce the stress, suppress cracks and breakage generated in the bonding member and the semiconductor element, and improve the reliability of the product.

In order to achieve the above object, according to the first aspect of the present invention, a metal stem (10) having a pressure detection diaphragm (11), a joining member (20) provided on the diaphragm, and a joining member are provided. A semiconductor element (30) that is provided and bonded to the diaphragm via a bonding member and detects distortion of the diaphragm, and
On the outer peripheral side of the semiconductor element on the bonding member, a stress absorbing material (40) that absorbs thermal stress resulting from the difference in thermal expansion coefficient between the bonding member and the metal stem is provided. Is fixed to the bonding member and is spaced apart from the semiconductor element, and the total thickness of the portion of the bonding member located on the outer peripheral side of the semiconductor element and the stress absorbing material located on the portion ( t2) is characterized in that it is thicker than the thickness (t1) of the portion of the bonding member located immediately below the semiconductor element.

  According to this, in the part located on the outer peripheral side of the semiconductor element and the part located directly below the semiconductor element in the joining member, the former is thicker due to the total thickness (t2) with the stress absorbing material. Therefore, the former of the two parts is less likely to be displaced by the stress from the metal stem due to the difference in thermal expansion coefficient than the latter.

  Therefore, according to the present invention, the thermal stress caused by the difference in thermal expansion between the joining member and the metal stem is reduced, cracks and breakage occurring in the joining member and the semiconductor element are suppressed, and the reliability of the product is improved. Can do.

Further, according to the present invention, the thickness of the joining member can be reduced at a portion of the joining member located immediately below the semiconductor element, so that the distortion of the diaphragm of the metal stem can be detected with high sensitivity by the semiconductor element. That is, according to the present invention, it is possible to improve the reliability of the product while ensuring the sensor sensitivity.
Furthermore, since the stress absorbing material is disposed apart from the semiconductor element, compared to the case where the stress absorbing material and the semiconductor element are in contact, the semiconductor element is less likely to receive stress from the stress absorbing material, The effect that it becomes easy to ensure the sensitivity of a semiconductor element can be expected.

  Furthermore, as in the invention described in claim 2, if the thermal expansion coefficient of the joining member and the stress absorbing material is not less than the thermal expansion coefficient of the semiconductor element and not more than the thermal expansion coefficient of the metal stem, the above claim The effect of item 1 is exhibited appropriately.

  Further, as in the invention described in claim 3, if the stress absorbing material has a continuous annular shape on the outer peripheral side of the semiconductor element, the stress absorbing material is formed on the entire outer periphery of the semiconductor element. Since an effect is exhibited, it is preferable.

  In addition, the code | symbol in the bracket | parenthesis of each means described in the claim and this column is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

It is a schematic sectional drawing which shows the principal part of the pressure sensor concerning embodiment of this invention. FIG. 2 is a top schematic plan view in FIG. 1. It is a graph which shows the specific effect of the stress absorption material in the said embodiment. FIG. 4 is a chart showing specific effects of the stress absorber following FIG. 3.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, parts that are the same or equivalent to each other are given the same reference numerals in the drawings for the sake of simplicity. Further, in FIG. 2, for easy identification of each part, for convenience, one-side oblique hatching is performed on the surface of the bonding member 20, dotted surface hatching is performed on the surface of the semiconductor element 30, and point hatching is performed on the surface of the stress absorber 40.

  The pressure sensor according to the present embodiment is mounted on, for example, an automobile and is applied to pressure measurement of fuel, oil, and the like. The pressure sensor is roughly divided into a metal stem 10 having a pressure detection diaphragm 11, a joining member 20 provided on the diaphragm 11, and a diaphragm 11 provided on the joining member 20 via the joining member 20. The semiconductor element 30 is joined.

  The metal stem 10 has a thin-walled diaphragm 11 as a closing portion on one end side and has a hollow cylindrical shape having an opening 12 on the other end side, and has a screw portion 10a on the outer peripheral side surface. The metal stem 10 is fixed to the attached member such as the fuel or oil pipe by screw connection by the screw portion 10a. In the metal stem 10, pressure by a pressure medium is introduced from the opening 12, and this pressure is applied to the inner surface of the diaphragm 11.

  The joining member 20 joins the outer surface of the diaphragm 11 and the semiconductor element 30. The joining member 20 is made of joining glass or the like, and has a layered shape with a thickness t1. Details of the bonding member 20 will be described later together with the stress absorber 40.

  The semiconductor element 30 detects distortion of the diaphragm 11 and has a typical rectangular plate shape here. The semiconductor element 30 is made of a silicon semiconductor formed by a semiconductor process.

  Specifically, the semiconductor element 30 functions as a detection unit that detects, as pressure, distortion generated when the diaphragm 11 is deformed by the pressure of the pressure medium introduced into the metal stem 10 from the opening 12. is there. The diaphragm 11 and the semiconductor element 30 influence the basic performance of the sensor.

  Although not shown, a circuit board (not shown) is provided outside the metal stem 10, and the semiconductor element 30 is electrically connected to the circuit board by a lead member, wire bonding, or the like. Thereby, the semiconductor element 30 is electrically connected to the ECU of the automobile or the like via the circuit board.

  For example, when fuel pressure (pressure medium) in the fuel pipe is introduced from the opening 12 of the metal stem 10 into the metal stem 10 (hollow portion), the diaphragm 11 is deformed by the pressure. Is converted into an electrical signal by the semiconductor element 30 and output to the circuit board to detect pressure.

  Here, on the bonding member 20, a stress absorbing material 40 is provided on the outer peripheral side of the semiconductor element 30 and is fixed to the bonding member 20. The stress absorbing material 40 absorbs thermal stress caused by the difference in thermal expansion coefficient between the joining member 20 and the metal stem 10. The stress absorbing material 40 is made of bonded glass or the like and forms a planar annular layer having a thickness t3.

  Here, the total thickness t <b> 2 (= t <b> 1 + t <b> 3) of the bonding member 20 on the outer peripheral side of the semiconductor element 11 and the stress absorbing material 40 positioned on the bonding element 20 is equal to that of the semiconductor element 30 in the bonding member 20. It is assumed to be thicker than the thickness t1 of the portion located immediately below.

  In the present embodiment, the stress absorbing material 40 has a continuous annular shape on the outer peripheral side of the semiconductor element 30. In the example of FIGS. 1 and 2, the stress absorbing material 40 has a planar annular shape (for example, an inner diameter of 6 mm and an outer diameter of 7.5 mm), but is a planar rectangular annular shape or a planar polygonal annular shape. Also good. Further, as shown in FIG. 2, the inner shell of the stress absorbing material 40 is disposed on the bonding member 20 so as to be separated from the outer shell of the semiconductor element 30.

[Material of each part 10-40 in the pressure sensor]
Next, the material and the like of each of the parts 10 to 40 in the pressure sensor will be specifically described. In the present embodiment, the thermal expansion coefficient of the joining member 20 is not less than the thermal expansion coefficient of the semiconductor element 30 and not more than the thermal expansion coefficient of the metal stem 10 as is typical.

  Further, also for the stress absorbing material 40, the thermal expansion coefficient of the stress absorbing material 40 is not less than the thermal expansion coefficient of the semiconductor element 30 and not more than the thermal expansion coefficient of the metal stem 10. That is, in this embodiment, the thermal expansion coefficients of the bonding member 20 and the stress absorbing material 40 are both equal to or higher than the thermal expansion coefficient of the semiconductor element 30 and lower than the thermal expansion coefficient of the metal stem 10.

  Examples of the joining member 20 and the stress absorbing material 40 include those whose main component is made of inorganic glass. More specifically, the joining member 20 and the stress absorbing material 40 of the present embodiment contain a filler capable of controlling the thermal expansion coefficient in an inorganic glass, and a paste-like glass formed by adding a solvent to the filler. The paste is solidified. Thus, the joining member 20 and the stress absorbing material 40 contain inorganic glass that provides a joining action as a main component.

  As said inorganic glass, what has a composition which can be joined at the temperature lower than the heat-resistant temperature of the semiconductor element 30 is employable. For example, lead-free glass containing components such as barium (Ba), bismuth (Bi), boron (B), silicon (Si), aluminum (Al), tin (Sn), vanadium (V), phosphorus (P), etc. Can be adopted. Moreover, you may employ | adopt lead glass containing lead (Pb). Since these glasses have a low melting point composition, they can be bonded at a low temperature (400 ° C. or lower) lower than the heat resistance temperature (for example, 470 ° C.) of the semiconductor element 30.

  Moreover, in order to adjust a thermal expansion coefficient etc., the joining member 20 and the stress absorber 40 of this embodiment contain the particle | grains which do not react with glass, ie, a filler. Examples of the filler include oxides such as cordierite, tungsten zirconate phosphate, alumina, silica, or iron (Fe), cobalt (Co), tungsten (W), copper (Cu), strontium (Sr), Oxides of various elements such as silver (Ag), niobium (Nb), tantalum (Ta), cerium (Ce), gallium (Ga), antimony (Sb), and tellurium (Te) can be employed.

  The particle size of the filler can be selected from 0.1 μm to 50 μm, and mainly depends on the thickness of the bonding member 20 and the stress absorbing material 40 and the surface roughness of the object to be bonded (metal stem 10 or semiconductor element 30). Is selected accordingly.

  Further, the material of the metal stem 10 of the present embodiment may be the same as that of the conventional Kovar, but here, the metal stem 10 is made of stainless steel and is formed by die machining or cutting.

More specifically, the metal stem 10 is made of SUS430, and has a thermal expansion coefficient of, for example, 120 × 10 ⁻⁷ / ° C. (in the range of 20 ° C. to 300 ° C.). Moreover, the thermal expansion coefficient of the semiconductor element 30 made of silicon is, for example, 30 × 10 ⁻⁷ / ° C. (in the range of 20 ° C. to 300 ° C.).

In the present embodiment, the thermal expansion coefficients of the joining member 20 and the stress absorbing material 40 are between the thermal expansion coefficient of the metal stem 10 and the thermal expansion coefficient of the semiconductor element 30 as described above. 20 is 56 × 10 ⁻⁷ / ° C. (in the range of 20 ° C. to 300 ° C.), and the stress absorber 40 is 49 to 69 × 10 ⁻⁷ / ° C. (in the range of 20 ° C. to 300 ° C.). It is. The thermal expansion coefficients of the joining member 20 and the stress absorbing material 40 can be easily adjusted by adjusting the amount of the filler added in the inorganic glass.

  Here, if the relationship between the thermal expansion coefficients is satisfied, the joining member 20 and the stress absorbing material 40 may have the same thermal expansion coefficient or different thermal expansion coefficients. Furthermore, although the joining member 20 and the stress absorbing material 40 are separate members, they may be made of the same material or different materials.

[First Example of Manufacturing Method]
Next, a method for manufacturing the pressure sensor will be described. First, a first example of this manufacturing method will be described. First, in a preparation process, the 1st glass paste as a raw material of the metal stem 10, the semiconductor element 30, and the joining member 20, and the 2nd glass paste as a raw material of the stress absorber 40 are prepared. Each of these glass pastes is a pasty glass containing the above filler in an inorganic glass.

  In the first manufacturing method, as a first step, the first glass paste is applied onto the diaphragm 11 and is melted and solidified by heat treatment to form the joining member 20. In this way, the bonded member 20 once cured on the diaphragm 11 is formed.

  Next, in the second step, the second glass paste is applied to the portion of the bonding member 20 located on the outer peripheral side of the semiconductor element 30 with the arrangement pattern of the stress absorbing material 40.

  Next, in the third step, the semiconductor element 30 is placed on the bonding member 20 inside the second glass paste and heat-treated. Thus, the second glass paste is melted and solidified to form the stress absorbing material 40, and the bonding member 20 is remelted and solidified to bond the semiconductor element 30 and the bonding member 20. This is a first example of the manufacturing method according to the present embodiment, whereby the pressure sensor shown in FIGS. 1 and 2 is completed.

[Second Example of Manufacturing Method]
Next, a second example of the manufacturing method of the pressure sensor will be described. First, in the preparation process, the first glass paste as the material of the metal stem 10, the semiconductor element 30, the joining member 20, and the first material as the material of the stress absorbing material 40, as in the manufacturing method of the first example. Prepare 2 glass paste.

  And in this 2nd manufacturing method, a 1st solid substance is obtained by apply | coating and drying the 1st glass paste on the diaphragm 11 as a 1st process. The first solid material is obtained by solidifying the first glass paste by evaporating the solvent in the paste not by melting but drying.

  Next, in the second step, a second glass paste is applied to the portion of the first solid material located on the outer peripheral side of the semiconductor element 30 with the arrangement pattern of the stress absorber 40, and this is further applied. A second solid is obtained by drying. The second solid material is obtained by solidifying the second glass paste by evaporating the solvent in the paste not by melting but drying.

  Next, in the third step, the semiconductor element 30 is placed inside the second solid material and heat-treated on the first solid material. Thus, in the third step, the first solid is melted and solidified to form the joining member 20, the semiconductor element 30 and the joining member 20 are joined, and the second solid is melted. The stress absorbing material 40 is formed by solidification. This is a second example of the manufacturing method according to the present embodiment, whereby the pressure sensor shown in FIGS. 1 and 2 is completed.

  The pressure sensor of this embodiment may be manufactured using either of these examples. Comparing the first example and the second example, in the case of the first example, the first glass paste is melted and solidified by the first step before the semiconductor element 30 is mounted on the bonding member 20. Thus, the joining member 20 is formed. Therefore, there exists an advantage that the void which exists in a 1st glass paste can be efficiently discharged | emitted from the whole surface of a 1st glass paste.

  On the other hand, in the case of the second example, after the semiconductor element 30 is mounted on the bonding member 20, the first solid material obtained by drying the first glass paste is melted and solidified to form the bonding member 20. I am doing so.

  Therefore, compared to the first example, the amount of voids present in the first glass paste is discharged because the surface of the first solid corresponding to the first glass paste is covered with the semiconductor element 30. Although it is disadvantageous in that respect, it is advantageous in that the labor and cost of heat treatment can be reduced in that the joining member 20 and the stress absorbing material 40 can be formed by heat treatment at the same time.

  Here, the manufacturing methods of the first example and the second example will be described more specifically. In the manufacturing method of each example, the application of each glass paste may be performed by a printing method, but may be performed by, for example, a dispenser device.

  In this case, typically, a dispenser device includes a nozzle that discharges the glass paste and a support mechanism that includes a metal stem 10 and is configured by a table that can be driven to position a workpiece. For example, when a glass paste having a viscosity of 10 to 50 Pa · s is used, the nozzle outlet diameter can be about 0.2 to 0.5 mm.

  Further, it is desirable to include a position control means for controlling the relative position of the nozzle with respect to the outer surface of the diaphragm 11 to which the glass paste is applied, and a position correction means for correcting the position of the nozzle when applying the paste. Such position control means and position correction means are constituted by an actuator, a computer, or the like.

  Further, in order to inspect the shapes of the bonding member 20 and the stress absorbing material 40 and eliminate those having an abnormal shape, a dispenser device having an image means for measuring the applied glass paste shape with a camera is desirable. . As such a camera, a CCD camera, a CMOS camera, or the like can be used, and inspection can be performed by a three-dimensional (3D) dimension measuring means.

  The CCD camera is a solid-state imaging device camera that is a charge coupled device (CCD), and the CMOS camera is a solid-state imaging device camera that is a complementary metal oxide semiconductor (Complementary Metal Oxide Semiconductor). is there.

  Further, it is desirable that the camera has an autofocus function. Specifically, it is desirable that the camera automatically focuses on the outer surface of the diaphragm 11 that is the application surface of the glass paste on the metal stem 10.

  Further, the shapes of the bonded member 20 and the stress absorbing material 40 after firing in the pressure sensor can also be inspected by the three-dimensional (3D) dimension measuring means using the above-described CCD camera, CMOS camera or the like.

[Effects]
By the way, according to this embodiment, in the part located in the outer peripheral side of the semiconductor element 30 and the part located directly under the semiconductor element 30 in the bonding member 20, the former is the total thickness of the stress absorber 40. The thickness is increased by t2. Therefore, the former of the two parts is less likely to be displaced by the stress from the metal stem 10 due to the difference in thermal expansion coefficient than the latter.

  More specifically, in this embodiment, the semiconductor element 30 is joined to the metal stem 10 by the glass as the joining member 20 being solidified in the course of cooling from melting. Therefore, the semiconductor element 30 and the joining member 20 generate thermal stress accompanying the shrinkage of the metal stem 10. Here, in this embodiment, the thermal stress is reduced by configuring the stress absorbing material 40 on the outer peripheral side of the semiconductor element 30.

  That is, since the metal stem 10 has a larger thermal expansion coefficient than the semiconductor element 30, the metal stem 10 contracts more than the semiconductor element 30 during the cooling process. As a result, tensile stress acts on the bonding member 20 directly below the semiconductor element 30 in the direction of the center of the pressure sensor (center of the diaphragm 11).

  On the other hand, the portion located on the outer peripheral side of the semiconductor element 30 in the bonding member 20 is thick due to the total thickness t2 with the stress absorbing material 40 and is difficult to be displaced by the tensile stress. The tensile stress acting on the member 20 is canceled as a whole. Therefore, the tensile stress acting on the bonding member 20 and the semiconductor element 30 is reduced, and bonding without cracks and breakage is realized in these members 20 and 30.

  Thus, according to the present embodiment, the thermal stress due to the difference in thermal expansion between the joining member 20 and the metal stem 10 is reduced, and cracks and breakage occurring in the joining member 20 and the semiconductor element 30 are suppressed. Product reliability can be improved.

  Further, according to the present embodiment, since the thickness of the bonding member 20 can be reduced as usual in a portion of the bonding member 20 that is located immediately below the semiconductor element 30, the distortion of the diaphragm 11 of the metal stem 10 can be reduced. The element 30 can be detected with high sensitivity. Thus, according to this embodiment, the reliability of the product can be improved while ensuring the sensor sensitivity.

  And according to this embodiment, the said effect is appropriate by making the thermal expansion coefficient of the joining member 20 and the stress absorption material 40 more than the thermal expansion coefficient of the semiconductor element 30, and below the thermal expansion coefficient of the metal stem 10. To show off.

  In the present embodiment, the stress absorbing material 40 has a continuous annular shape on the outer peripheral side of the semiconductor element 30. According to this, the above-described effect by the stress absorbing material 40 is exhibited on the entire outer periphery of the semiconductor element 30.

  Further, although the stress absorbing material 40 may be disposed in contact with the semiconductor element 30, in the present embodiment, the stress absorbing material 40 is disposed separately from the semiconductor element 30. By adopting the separated arrangement form in this way, the semiconductor element 30 becomes less susceptible to the stress from the stress absorbing material 40 than when the contact arrangement form is adopted, and the sensitivity of the semiconductor element 30 is easily secured. There are advantages.

  Moreover, in this embodiment, the metal stem 10 is made of stainless steel, so that it is possible to provide a pressure sensor that is superior in pressure resistance and suitable for high pressure measurement compared to a conventional metal stem made of Kovar. In such a high-pressure type pressure sensor, the above-described effect of the stress absorbing material 40 can be exhibited.

  Next, Examples 1 to 18 shown in FIG. 3 and FIG. 4 and Comparative Examples shown in FIG. 3 and FIG. A more specific description will be given with reference to FIGS. Here, Comparative Examples 1 and 2 have a configuration in which the stress absorbing material 40 is omitted.

In the examples of FIGS. 3 and 4, the glass paste was prepared as follows. Here, V ₂ O ₅ , P ₂ O ₅ , TeO ₂ , and Fe ₂ O ₃ were used as the glass frit used as the glass paste raw material for the bonding member 20 and the stress absorbing material 40.

  The composition of the glass frit was such that V was 50% by weight, P was 15% by weight, Te was 25% by weight, and Fe was 10% by weight in terms of oxide. The above oxides were prepared and mixed so as to have the above composition.

  And this mixed raw material was put into the Pt crucible, it heated up at 10 degree-C / min with the baking furnace, and it hold | maintained at 900-950 degreeC for 1 hour, and obtained glass. The obtained glass was taken out from the Pt crucible and then pulverized to a particle size of less than 20 μm by pulverization. Subsequently, a sieve was passed to obtain a glass frit having a particle size of 3 μm.

Next, fillers, which are materials for controlling the thermal expansion coefficient, were prepared in the bonding member 20 and the stress absorbing material 40, and various mixed powders were obtained by mixing the fillers and the glass frit having a particle size of 3 μm. Here, tungsten zirconate phosphate (Zr ₂ WP ₂ O ₁₂ ), niobium pentoxide (Nb ₂ O ₅ ), and tungsten oxide (WO ₃ ) were used as fillers.

  And in order to make the said mixed powder into a glass paste, butyl carbyl acetate as a solvent and ethyl cellulose as a binder were added and mixed to the said mixed powder, and the glass paste was obtained.

  3 and 4, the glass frit has the same composition, and various paste members 20 and stress absorbers 40 having different coefficients of thermal expansion are produced by producing glass pastes with different amounts of filler. To form.

  And in the example of FIG. 3, FIG. 4, the glass paste used as the joining member 20 and the stress absorber 40 adjusts the viscosity to 10 to 50 Pa · s depending on the amount of the solvent added, and this is dispensed with a dispenser device. It apply | coated on the diaphragm 11 of the metal stem 10 which consists of SUS430.

  And about this apply | coated glass paste, the manufacturing method of the 1st example or 2nd example of this embodiment mentioned above is applied, and it melts and solidifies by drying, heating, and joining member 20 and stress absorption Material 40 was formed.

In each of Examples 1 to 18 and Comparative Examples 1 and 2 in FIGS. 3 and 4, the thermal expansion coefficient of the joining member 20 is constant at 56 × 10 ⁻⁷ / ° C. (in the range of 20 ° C. to 300 ° C.). The thickness t1 of the joining member 20 was controlled in the range of 50 to 100 μm based on the surface of the metal stem 10, that is, the surface of the diaphragm 11.

Moreover, the thermal expansion coefficient of the stress absorber 40 is changed in a range of 49 to 69 × 10 ⁻⁷ / ° C. (in the range of 20 ° C. to 300 ° C.), and the thickness t3 of the stress absorber 40 is 50 to 50. Control was performed in the range of 150 μm. Note that the thickness of the semiconductor element 30 was 100 μm in all examples. The thicknesses of the semiconductor element 30 and the bonding member 20 are typical thicknesses for this type of pressure sensor.

  And about each example, the crack and destruction which generate | occur | produced in the semiconductor element 30 and the joining member 20 after joining were investigated. As a result, as shown in FIGS. 3 and 4, in Examples 1 to 18, the semiconductor element 30 and the joining member 20 were not cracked or broken, and the joining form was secured in all the evaluation samples. In Comparative Examples 1 and 2 having the configuration in which the stress absorbing material 20 is omitted, the semiconductor element 30 and the joining member 40 are cracked or broken.

  Thus, according to this embodiment, even when the metal stem 10 made of stainless steel suitable for the high pressure type is used, the semiconductor element 30 is appropriately attached to the metal stem 10 via the bonding member 20 made of bonding glass. It can be joined.

(Other embodiments)
In the above embodiment, the stress absorbing material 40 is arranged in a continuous annular shape on the outer peripheral side of the semiconductor element 30, but is not limited to this, and for example, intermittently arranged in a circular shape. It may be what was done.

  Moreover, in the said embodiment, although the semiconductor element 30 was a planar rectangular plate shape, as the semiconductor element 30, a planar shape may be circular or the polygon by which the corner | angular part was R-processed. When the semiconductor element 30 is a plane rectangle, the thermal stress is likely to be concentrated at the corner, and cracks are likely to occur at the corner. In this regard, if the semiconductor element 30 is a circular plate or a polygonal plate having corners that are R-processed, it is easy to suppress the thermal stress concentration in the semiconductor element 30.

  Moreover, in the said embodiment, although the joining member 20 and the stress absorption material 40 shall consist of inorganic glass as a main component, oxides, such as an alumina and a silica, may be sufficient as the said main component.

  Moreover, in the said manufacturing method, when test | inspecting the application shape of each glass paste by a dispenser apparatus, and the shape of the joining member 20 after baking in the pressure sensor, and the shape of the stress absorber 40, it is a paste shape by a solid (3D) dimension measurement means. An inspection may be performed. According to this, it is possible to perform shape determination with higher speed and higher accuracy. Such three-dimensional (3D) dimension measurement is based on, for example, a light cutting method.

  In addition to the combination of the above-described embodiments, the above-described embodiments may be appropriately combined within the possible range, and the above-described embodiments are not limited to the illustrated examples.

DESCRIPTION OF SYMBOLS 10 Metal stem 11 Diaphragm 20 Joining member 30 Semiconductor element 40 Stress absorption material t1 Thickness of joining member t2 Total thickness of joining member and stress absorption material located on it

Claims (8)

A metal stem (10) having a diaphragm (11) for pressure detection;
A joining member (20) provided on the diaphragm;
A semiconductor element (30) provided on the joining member, joined to the diaphragm via the joining member, and detecting distortion of the diaphragm;
On the bonding member, a stress absorbing material (40) that absorbs thermal stress caused by a difference in thermal expansion coefficient between the bonding member and the metal stem is provided on the outer peripheral side of the semiconductor element. ,
The stress absorbing material, as well is fixed to the joining member, it is disposed apart from the semiconductor element,
The total thickness (t2) of the part located on the outer peripheral side of the semiconductor element in the joining member and the stress absorbing material located on the part is the part located directly below the semiconductor element in the joining member A pressure sensor characterized by being thicker than the thickness (t1).   2. The pressure sensor according to claim 1, wherein a thermal expansion coefficient of the joining member and the stress absorbing material is not less than a thermal expansion coefficient of the semiconductor element and not more than a thermal expansion coefficient of the metal stem.   The pressure sensor according to claim 1, wherein the stress absorbing material has a continuous annular shape on an outer peripheral side of the semiconductor element. The pressure sensor according to any one of claims 1 to 3 , wherein the semiconductor element has a circular planar shape or a polygonal shape in which corners are R-processed. The pressure sensor according to any one of claims 1 to 4 , wherein the joining member and the stress absorbing material are mainly composed of inorganic glass. The pressure sensor according to any one of claims 1 to 5 , wherein the metal stem is made of stainless steel. A metal stem (10) having a diaphragm (11) for pressure detection;
A joining member (20) provided on the diaphragm;
A semiconductor element (30) provided on the joining member, joined to the diaphragm via the joining member, and detecting distortion of the diaphragm;
On the bonding member, a stress absorbing material (40) that absorbs thermal stress caused by a difference in thermal expansion coefficient between the bonding member and the metal stem is provided on the outer peripheral side of the semiconductor element. ,
The stress absorbing material is fixed to the joining member,
The total thickness (t2) of the part located on the outer peripheral side of the semiconductor element in the joining member and the stress absorbing material located on the part is the part located directly below the semiconductor element in the joining member A pressure sensor manufacturing method that is thicker than the thickness (t1) of
A preparation step of preparing the metal stem, the semiconductor element, a first glass paste as a material of the joining member, and a second glass paste as a material of the stress absorber;
Applying the first glass paste on the diaphragm, heat-treating it to melt and solidify it, and forming the joining member;
A second step of applying the second glass paste to a portion of the bonding member located on the outer peripheral side of the semiconductor element;
The semiconductor element is placed on the inside of the second glass paste on the bonding member, and heat-treated to melt and solidify the second glass paste to form the stress absorbing material, and And a third step of bonding the semiconductor element and the bonding member by re-melting and solidifying the bonding member. A metal stem (10) having a diaphragm (11) for pressure detection;
A joining member (20) provided on the diaphragm;
A semiconductor element (30) provided on the joining member, joined to the diaphragm via the joining member, and detecting distortion of the diaphragm;
On the bonding member, a stress absorbing material (40) that absorbs thermal stress caused by a difference in thermal expansion coefficient between the bonding member and the metal stem is provided on the outer peripheral side of the semiconductor element. ,
The stress absorbing material is fixed to the joining member,
The total thickness (t2) of the part located on the outer peripheral side of the semiconductor element in the joining member and the stress absorbing material located on the part is the part located directly below the semiconductor element in the joining member A pressure sensor manufacturing method that is thicker than the thickness (t1) of
A preparation step of preparing the metal stem, the semiconductor element, a first glass paste as a material of the joining member, and a second glass paste as a material of the stress absorber;
A first step of obtaining a first solid by applying and drying the first glass paste on the diaphragm; and
A second step of obtaining a second solid material by applying the second glass paste to a portion of the first solid material located on an outer peripheral side of the semiconductor element and drying the first solid material; On the solid material, the semiconductor element is placed inside the second solid material and subjected to heat treatment to melt and solidify the first solid material, thereby forming the joining member. And a third step of bonding the element and the bonding member and melting and solidifying the second solid material to form the stress absorbing material.

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